diff --git a/desktop/src-tauri/src/commands/collections.rs b/desktop/src-tauri/src/commands/collections.rs
index 291e210fb7..4111998e57 100644
--- a/desktop/src-tauri/src/commands/collections.rs
+++ b/desktop/src-tauri/src/commands/collections.rs
@@ -1,31 +1,16 @@
-use std::{
-    collections::HashSet,
-    path::{Path, PathBuf},
-    process::Stdio,
-    time::Duration,
-};
+use std::path::PathBuf;
 
 use buzz_collections_pkg::{
     collections_db_path_for_app_data_dir, Collection, CollectionMember, CollectionReference,
     CollectionScope, CollectionWithMembers, CollectionsError, CollectionsStore,
 };
-use chrono::{DateTime, NaiveDateTime, SecondsFormat, Utc};
-use serde::{Deserialize, Serialize};
-use serde_json::Value;
+use serde::Deserialize;
 use tauri::{AppHandle, Manager};
-use tokio::io::{AsyncRead, AsyncReadExt};
-use tokio::process::Command;
 use uuid::Uuid;
 
-const CALENDAR_DISCOVERY_TIMEOUT: Duration = Duration::from_secs(20);
-const CALENDAR_TOOL_TIMEOUT_SECS: &str = "15";
-const DRIVE_PROCESS_TIMEOUT: Duration = Duration::from_secs(12);
-const DRIVE_TOOL_TIMEOUT_SECS: &str = "10";
-const CALENDAR_ACTIVITY_TIMEOUT: Duration = Duration::from_secs(45);
-const MAX_ACTIVITY_DOCUMENTS: usize = 16;
-const MAX_CALENDAR_STDOUT_BYTES: usize = 1024 * 1024;
-const MAX_CALENDAR_STDERR_BYTES: usize = 64 * 1024;
-const CALENDAR_UNAVAILABLE: &str = "Optional Google Calendar discovery is unavailable";
+mod calendar;
+
+pub use calendar::*;
 
 #[derive(Debug, Deserialize)]
 pub struct CreateCollectionInput {
@@ -61,75 +46,6 @@ pub struct AddCollectionMemberInput {
     pub label: Option<String>,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
-pub struct CollectionDiscoveredLink {
-    pub url: String,
-    pub label: String,
-    pub kind: String,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
-pub struct CollectionCalendarActivity {
-    pub action_type: String,
-    pub timestamp: String,
-    pub actor_display_name: Option<String>,
-    pub actor_email: Option<String>,
-    pub document_title: String,
-    pub document_url: String,
-    pub document_file_id: String,
-    pub source_calendar_url: String,
-    pub source_attachment_url: String,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
-pub struct CollectionActivitySourceError {
-    pub source_url: String,
-    pub message: String,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
-pub struct CollectionCalendarActivityResult {
-    pub activities: Vec<CollectionCalendarActivity>,
-    pub errors: Vec<CollectionActivitySourceError>,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-struct DriveDocumentMetadata {
-    file_id: String,
-    title: String,
-    url: String,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-struct ParsedDriveActivity {
-    action_type: String,
-    timestamp: String,
-    actor_display_name: Option<String>,
-    actor_email: Option<String>,
-}
-
-#[derive(Debug, Deserialize)]
-struct CalendarToolResponse {
-    #[serde(default)]
-    result: Option<CalendarEventResult>,
-    #[serde(default)]
-    attachments: Vec<CalendarAttachment>,
-}
-
-#[derive(Debug, Deserialize)]
-struct CalendarEventResult {
-    #[serde(default)]
-    attachments: Vec<CalendarAttachment>,
-}
-
-#[derive(Debug, Deserialize)]
-struct CalendarAttachment {
-    #[serde(rename = "fileUrl")]
-    file_url: String,
-    #[serde(default)]
-    title: String,
-}
-
 #[tauri::command]
 pub async fn list_collections(
     relay_url: String,
@@ -251,295 +167,6 @@ pub async fn remove_collection_member(
     .await
 }
 
-/// Discover current document attachments for a linked Google Calendar event.
-///
-/// Collections keep the calendar event as the explicit membership edge. This
-/// optional local resolver reads the user's already-connected Calendar account
-/// and returns ephemeral children; it never writes those children to SQLite.
-#[tauri::command]
-pub async fn discover_collection_calendar_links(
-    url: String,
-) -> Result<Vec<CollectionDiscoveredLink>, String> {
-    validate_google_calendar_event_url(&url)?;
-    let sq_path = crate::managed_agents::resolve_command("sq")
-        .ok_or_else(|| format!("{CALENDAR_UNAVAILABLE}: `sq` was not found on this device"))?;
-
-    fetch_calendar_links(&sq_path, &url).await
-}
-
-/// Discover ephemeral edit and comment activity for Google Drive documents
-/// attached to an explicit Google Calendar event.
-#[tauri::command]
-pub async fn discover_collection_calendar_activity(
-    calendar_url: String,
-    start_time: String,
-    end_time: Option<String>,
-) -> Result<CollectionCalendarActivityResult, String> {
-    validate_google_calendar_event_url(&calendar_url)?;
-    validate_activity_window(&start_time, end_time.as_deref())?;
-    let sq_path = crate::managed_agents::resolve_command("sq").ok_or_else(|| {
-        format!(
-            "Optional Google Calendar activity discovery is unavailable for {calendar_url}: `sq` was not found on this device"
-        )
-    })?;
-
-    tokio::time::timeout(
-        CALENDAR_ACTIVITY_TIMEOUT,
-        discover_calendar_activity(&sq_path, &calendar_url, &start_time, end_time.as_deref()),
-    )
-    .await
-    .map_err(|_| {
-        format!(
-            "Optional Google Calendar activity discovery is unavailable for {calendar_url}: lookup timed out"
-        )
-    })?
-}
-
-async fn fetch_calendar_links(
-    sq_path: &Path,
-    url: &str,
-) -> Result<Vec<CollectionDiscoveredLink>, String> {
-    let args = [
-        "agent-tools",
-        "google-calendar",
-        "get-calendar-event",
-        "--event-id",
-        url,
-        "--calendar-id",
-        "primary",
-        "--output",
-        "json",
-        "--timeout",
-        CALENDAR_TOOL_TIMEOUT_SECS,
-    ];
-    let stdout = run_sq_command(
-        sq_path,
-        &args,
-        CALENDAR_DISCOVERY_TIMEOUT,
-        CALENDAR_UNAVAILABLE,
-    )
-    .await?;
-    parse_calendar_links(&stdout).map_err(|error| format!("{CALENDAR_UNAVAILABLE}: {error}"))
-}
-
-async fn discover_calendar_activity(
-    sq_path: &Path,
-    calendar_url: &str,
-    start_time: &str,
-    end_time: Option<&str>,
-) -> Result<CollectionCalendarActivityResult, String> {
-    let links = fetch_calendar_links(sq_path, calendar_url)
-        .await
-        .map_err(|error| {
-            format!(
-                "Optional Google Calendar activity discovery is unavailable for {calendar_url}: {error}"
-            )
-        })?;
-    let mut documents = Vec::new();
-    let mut seen_file_ids = HashSet::new();
-    for link in links {
-        let Some(file_id) = google_drive_file_id(&link.url) else {
-            continue;
-        };
-        if seen_file_ids.insert(file_id.clone()) {
-            documents.push((file_id, link.url, link.label));
-        }
-    }
-
-    let mut result = CollectionCalendarActivityResult {
-        activities: Vec::new(),
-        errors: Vec::new(),
-    };
-    if documents.len() > MAX_ACTIVITY_DOCUMENTS {
-        result.errors.push(CollectionActivitySourceError {
-            source_url: calendar_url.to_string(),
-            message: format!(
-                "Only the first {MAX_ACTIVITY_DOCUMENTS} attached Drive documents were checked"
-            ),
-        });
-        documents.truncate(MAX_ACTIVITY_DOCUMENTS);
-    }
-
-    for (file_id, attachment_url, attachment_label) in documents {
-        let metadata = match fetch_drive_metadata(sq_path, &file_id).await {
-            Ok(metadata) => metadata,
-            Err(message) => {
-                result.errors.push(CollectionActivitySourceError {
-                    source_url: attachment_url,
-                    message: format!("{attachment_label} ({file_id}): {message}"),
-                });
-                continue;
-            }
-        };
-        let activities = match fetch_drive_activity(sq_path, &file_id, start_time, end_time).await {
-            Ok(activities) => activities,
-            Err(message) => {
-                result.errors.push(CollectionActivitySourceError {
-                    source_url: attachment_url,
-                    message: format!("{} ({file_id}): {message}", metadata.title),
-                });
-                continue;
-            }
-        };
-        result
-            .activities
-            .extend(
-                activities
-                    .into_iter()
-                    .map(|activity| CollectionCalendarActivity {
-                        action_type: activity.action_type,
-                        timestamp: activity.timestamp,
-                        actor_display_name: activity.actor_display_name,
-                        actor_email: activity.actor_email,
-                        document_title: metadata.title.clone(),
-                        document_url: metadata.url.clone(),
-                        document_file_id: metadata.file_id.clone(),
-                        source_calendar_url: calendar_url.to_string(),
-                        source_attachment_url: attachment_url.clone(),
-                    }),
-            );
-    }
-
-    result.activities.sort_by(|left, right| {
-        right
-            .timestamp
-            .cmp(&left.timestamp)
-            .then_with(|| left.document_file_id.cmp(&right.document_file_id))
-            .then_with(|| left.action_type.cmp(&right.action_type))
-    });
-    result.activities.dedup_by(|left, right| {
-        left.document_file_id == right.document_file_id
-            && left.action_type == right.action_type
-            && left.timestamp == right.timestamp
-            && left.actor_email == right.actor_email
-            && left.actor_display_name == right.actor_display_name
-    });
-    Ok(result)
-}
-
-async fn fetch_drive_metadata(
-    sq_path: &Path,
-    file_id: &str,
-) -> Result<DriveDocumentMetadata, String> {
-    let args = [
-        "agent-tools",
-        "google-drive",
-        "get-file-metadata",
-        "--file-id-or-url",
-        file_id,
-        "--raw",
-        "--timeout",
-        DRIVE_TOOL_TIMEOUT_SECS,
-    ];
-    let unavailable = "Optional Google Drive metadata is unavailable";
-    let output = run_sq_command(sq_path, &args, DRIVE_PROCESS_TIMEOUT, unavailable).await?;
-    parse_drive_metadata(&output, file_id).map_err(|error| format!("{unavailable}: {error}"))
-}
-
-async fn fetch_drive_activity(
-    sq_path: &Path,
-    file_id: &str,
-    start_time: &str,
-    end_time: Option<&str>,
-) -> Result<Vec<ParsedDriveActivity>, String> {
-    let mut args = vec![
-        "agent-tools",
-        "google-drive",
-        "activity",
-        "--start-time",
-        start_time,
-    ];
-    if let Some(end_time) = end_time {
-        args.extend(["--end-time", end_time]);
-    }
-    args.extend([
-        "--item-id",
-        file_id,
-        "--activity-type",
-        "edit",
-        "comment",
-        "--lookup-people",
-        "--raw",
-        "--timeout",
-        DRIVE_TOOL_TIMEOUT_SECS,
-    ]);
-    let unavailable = "Optional Google Drive activity is unavailable";
-    let output = run_sq_command(sq_path, &args, DRIVE_PROCESS_TIMEOUT, unavailable).await?;
-    parse_drive_activity(&output, file_id).map_err(|error| format!("{unavailable}: {error}"))
-}
-
-async fn run_sq_command(
-    sq_path: &Path,
-    args: &[&str],
-    process_timeout: Duration,
-    unavailable: &str,
-) -> Result<Vec<u8>, String> {
-    let mut command = Command::new(sq_path);
-    command
-        .args(args)
-        .stdin(Stdio::null())
-        .stdout(Stdio::piped())
-        .stderr(Stdio::piped())
-        .kill_on_drop(true);
-
-    let mut child = command
-        .spawn()
-        .map_err(|error| format!("{unavailable}: failed to start `sq`: {error}"))?;
-    let stdout = child
-        .stdout
-        .take()
-        .ok_or_else(|| format!("{unavailable}: failed to capture `sq` output"))?;
-    let stderr = child
-        .stderr
-        .take()
-        .ok_or_else(|| format!("{unavailable}: failed to capture `sq` errors"))?;
-
-    let (status, stdout, stderr) = tokio::time::timeout(process_timeout, async move {
-        let (stdout, stderr, status) = tokio::join!(
-            read_bounded(stdout, MAX_CALENDAR_STDOUT_BYTES),
-            read_bounded(stderr, MAX_CALENDAR_STDERR_BYTES),
-            child.wait(),
-        );
-        Ok::<_, std::io::Error>((status?, stdout?, stderr?))
-    })
-    .await
-    .map_err(|_| format!("{unavailable}: lookup timed out"))?
-    .map_err(|error| format!("{unavailable}: failed while running `sq`: {error}"))?;
-    if !status.success() {
-        return Err(format!(
-            "{unavailable}: {}",
-            first_safe_line(&stderr).unwrap_or("tool lookup failed")
-        ));
-    }
-    Ok(stdout)
-}
-
-async fn read_bounded(
-    reader: impl AsyncRead + Unpin,
-    max_bytes: usize,
-) -> Result<Vec<u8>, std::io::Error> {
-    let mut bytes = Vec::new();
-    reader
-        .take((max_bytes + 1) as u64)
-        .read_to_end(&mut bytes)
-        .await?;
-    if bytes.len() > max_bytes {
-        return Err(std::io::Error::new(
-            std::io::ErrorKind::InvalidData,
-            "tool response exceeded the size limit",
-        ));
-    }
-    Ok(bytes)
-}
-
-fn first_safe_line(stderr: &[u8]) -> Option<&str> {
-    std::str::from_utf8(stderr)
-        .ok()?
-        .lines()
-        .map(str::trim)
-        .find(|line| !line.is_empty() && !line.chars().any(char::is_control))
-}
-
 fn database_path(app: &AppHandle) -> Result<PathBuf, String> {
     let app_data_dir = app
         .path()
@@ -569,843 +196,3 @@ fn parse_uuid(value: &str, field: &str) -> Result<Uuid, String> {
 fn render_error(error: CollectionsError) -> String {
     error.to_string()
 }
-
-fn validate_google_calendar_event_url(raw: &str) -> Result<(), String> {
-    if raw != raw.trim() || raw.len() > 8 * 1024 || raw.chars().any(char::is_control) {
-        return Err("invalid Google Calendar event URL".to_string());
-    }
-    let url = url::Url::parse(raw).map_err(|_| "invalid Google Calendar event URL".to_string())?;
-    let is_google_host = matches!(
-        url.host_str(),
-        Some("www.google.com" | "calendar.google.com")
-    );
-    let event_ids = url
-        .query_pairs()
-        .filter(|(key, _)| key == "eid")
-        .collect::<Vec<_>>();
-    if url.scheme() != "https"
-        || !is_google_host
-        || !url.username().is_empty()
-        || url.password().is_some()
-        || url.port().is_some()
-        || url.path() != "/calendar/event"
-        || url.fragment().is_some()
-        || event_ids.len() != 1
-        || event_ids[0].1.is_empty()
-        || event_ids[0].1.chars().any(char::is_control)
-    {
-        return Err("URL is not a supported Google Calendar event".to_string());
-    }
-    Ok(())
-}
-
-fn validate_activity_window(start_time: &str, end_time: Option<&str>) -> Result<(), String> {
-    let start = DateTime::parse_from_rfc3339(start_time)
-        .map_err(|_| "invalid Drive activity start time; expected RFC 3339".to_string())?;
-    if let Some(end_time) = end_time {
-        let end = DateTime::parse_from_rfc3339(end_time)
-            .map_err(|_| "invalid Drive activity end time; expected RFC 3339".to_string())?;
-        if end <= start {
-            return Err("Drive activity end time must be after start time".to_string());
-        }
-    }
-    Ok(())
-}
-
-fn google_drive_file_id(raw: &str) -> Option<String> {
-    if raw != raw.trim() || raw.len() > 8 * 1024 || raw.chars().any(char::is_control) {
-        return None;
-    }
-    let url = url::Url::parse(raw).ok()?;
-    if url.scheme() != "https"
-        || !url.username().is_empty()
-        || url.password().is_some()
-        || url.port().is_some()
-        || url.fragment().is_some()
-    {
-        return None;
-    }
-    let host = url.host_str()?;
-    let segments = url.path_segments()?.collect::<Vec<_>>();
-    let candidate = match host {
-        "docs.google.com"
-            if segments.first() == Some(&"document") && segments.get(1) == Some(&"d") =>
-        {
-            segments.get(2).copied()
-        }
-        "drive.google.com"
-            if segments.first() == Some(&"file") && segments.get(1) == Some(&"d") =>
-        {
-            segments.get(2).copied()
-        }
-        "drive.google.com" if url.path() == "/open" => {
-            let ids = url
-                .query_pairs()
-                .filter(|(key, _)| key == "id")
-                .map(|(_, value)| value.into_owned())
-                .collect::<Vec<_>>();
-            if ids.len() == 1 {
-                return valid_drive_file_id(&ids[0]).then(|| ids[0].clone());
-            }
-            None
-        }
-        _ => None,
-    }?;
-    valid_drive_file_id(candidate).then(|| candidate.to_string())
-}
-
-fn valid_drive_file_id(candidate: &str) -> bool {
-    (10..=128).contains(&candidate.len())
-        && candidate
-            .bytes()
-            .all(|byte| byte.is_ascii_alphanumeric() || matches!(byte, b'_' | b'-'))
-}
-
-fn parse_drive_metadata(
-    output: &[u8],
-    expected_file_id: &str,
-) -> Result<DriveDocumentMetadata, String> {
-    let value: Value = serde_json::from_slice(output)
-        .map_err(|error| format!("invalid Drive metadata response: {error}"))?;
-    if let Some(metadata) = find_drive_metadata(&value, expected_file_id) {
-        return Ok(metadata);
-    }
-    let mut texts = Vec::new();
-    collect_content_text(&value, &mut texts);
-    texts
-        .iter()
-        .find_map(|text| parse_drive_metadata_text(text, expected_file_id))
-        .ok_or_else(|| "metadata did not identify the attached Google document".to_string())
-}
-
-fn find_drive_metadata(value: &Value, expected_file_id: &str) -> Option<DriveDocumentMetadata> {
-    match value {
-        Value::Object(object) => {
-            let file_id = ["id", "fileId", "file_id"]
-                .iter()
-                .find_map(|key| object.get(*key).and_then(Value::as_str));
-            let mime_type = ["mimeType", "mime_type"]
-                .iter()
-                .find_map(|key| object.get(*key).and_then(Value::as_str));
-            let title = ["name", "title"]
-                .iter()
-                .find_map(|key| object.get(*key).and_then(Value::as_str));
-            let document_url = ["webViewLink", "web_view_link", "url"]
-                .iter()
-                .find_map(|key| object.get(*key).and_then(Value::as_str));
-            if file_id == Some(expected_file_id)
-                && mime_type == Some("application/vnd.google-apps.document")
-            {
-                let title = title?.trim();
-                let document_url = document_url?.trim();
-                if !title.is_empty()
-                    && !title.chars().any(char::is_control)
-                    && google_drive_file_id(document_url).as_deref() == Some(expected_file_id)
-                {
-                    return Some(DriveDocumentMetadata {
-                        file_id: expected_file_id.to_string(),
-                        title: title.to_string(),
-                        url: document_url.to_string(),
-                    });
-                }
-            }
-            for child in object.values() {
-                if let Some(metadata) = find_drive_metadata(child, expected_file_id) {
-                    return Some(metadata);
-                }
-            }
-            None
-        }
-        Value::Array(values) => values
-            .iter()
-            .find_map(|child| find_drive_metadata(child, expected_file_id)),
-        Value::String(text) => parse_embedded_json(text)
-            .as_ref()
-            .and_then(|embedded| find_drive_metadata(embedded, expected_file_id)),
-        _ => None,
-    }
-}
-
-fn parse_embedded_json(text: &str) -> Option<Value> {
-    let trimmed = text.trim();
-    let trimmed = trimmed
-        .strip_prefix("```json")
-        .or_else(|| trimmed.strip_prefix("```"))
-        .unwrap_or(trimmed)
-        .strip_suffix("```")
-        .unwrap_or(trimmed)
-        .trim();
-    serde_json::from_str(trimmed).ok()
-}
-
-fn parse_drive_metadata_text(text: &str, expected_file_id: &str) -> Option<DriveDocumentMetadata> {
-    let mut file_id = None;
-    let mut title = None;
-    let mut mime_type = None;
-    let mut document_url = None;
-    for line in text.lines() {
-        let line = line.trim().trim_start_matches(['-', '*', '#']).trim();
-        let Some((key, value)) = line.split_once(':') else {
-            continue;
-        };
-        let key = key
-            .trim_matches(|character: char| {
-                matches!(character, '*' | '`') || character.is_whitespace()
-            })
-            .to_ascii_lowercase();
-        let value = value.trim_matches(|character: char| {
-            matches!(character, '*' | '`') || character.is_whitespace()
-        });
-        match key.as_str() {
-            "id" | "file id" => file_id = Some(value),
-            "name" | "title" => title = Some(value),
-            "mime type" | "mimetype" => mime_type = Some(value),
-            "web view link" | "webviewlink" | "url" => document_url = Some(value),
-            _ => {}
-        }
-    }
-    if file_id != Some(expected_file_id)
-        || mime_type != Some("application/vnd.google-apps.document")
-    {
-        return None;
-    }
-    let title = title?;
-    let document_url = document_url?;
-    if title.is_empty()
-        || title.chars().any(char::is_control)
-        || google_drive_file_id(document_url).as_deref() != Some(expected_file_id)
-    {
-        return None;
-    }
-    Some(DriveDocumentMetadata {
-        file_id: expected_file_id.to_string(),
-        title: title.to_string(),
-        url: document_url.to_string(),
-    })
-}
-
-fn parse_drive_activity(
-    output: &[u8],
-    expected_file_id: &str,
-) -> Result<Vec<ParsedDriveActivity>, String> {
-    let Some(text) = drive_activity_text(output)? else {
-        return Ok(Vec::new());
-    };
-    let mut activities = text
-        .lines()
-        .filter_map(|line| parse_drive_activity_line(line, expected_file_id))
-        .collect::<Vec<_>>();
-    activities.sort_by(|left, right| right.timestamp.cmp(&left.timestamp));
-    activities.dedup();
-    if activities.is_empty() && !is_empty_activity_text(&text) {
-        return Err(
-            "Drive activity response contained no recognized edit or comment events".into(),
-        );
-    }
-    Ok(activities)
-}
-
-fn is_empty_activity_text(text: &str) -> bool {
-    let text = text.trim();
-    if text.is_empty() {
-        return true;
-    }
-    let lowercase = text.to_ascii_lowercase();
-    if lowercase.contains("no activity")
-        || lowercase.contains("no recent activity")
-        || lowercase.contains("no drive activity")
-        || lowercase.contains("no matching activity")
-        || lowercase.contains("no events")
-    {
-        return true;
-    }
-    parse_embedded_json(text)
-        .as_ref()
-        .is_some_and(is_explicit_empty_activity_value)
-}
-
-fn drive_activity_text(output: &[u8]) -> Result<Option<String>, String> {
-    let raw = std::str::from_utf8(output)
-        .map_err(|_| "Drive activity response was not UTF-8".to_string())?;
-    if raw.trim().is_empty() {
-        return Ok(None);
-    }
-    let Ok(value) = serde_json::from_str::<Value>(raw) else {
-        return Ok(Some(raw.to_string()));
-    };
-    let mut texts = Vec::new();
-    collect_content_text(&value, &mut texts);
-    texts.retain(|text| !text.trim().is_empty());
-    if texts.is_empty() && is_explicit_empty_activity_response(&value) {
-        return Ok(None);
-    }
-    if texts.is_empty() {
-        return Err("Drive activity response did not contain text content".into());
-    }
-    Ok(Some(texts.join("\n")))
-}
-
-fn is_explicit_empty_activity_response(value: &Value) -> bool {
-    match value {
-        Value::Object(object) => {
-            if object.get("is_error").and_then(Value::as_bool) == Some(true)
-                || object.get("isError").and_then(Value::as_bool) == Some(true)
-            {
-                return false;
-            }
-            [
-                "content",
-                "activities",
-                "activity",
-                "events",
-                "items",
-                "result",
-            ]
-            .iter()
-            .any(|key| {
-                object
-                    .get(*key)
-                    .is_some_and(is_explicit_empty_activity_value)
-            })
-        }
-        _ => false,
-    }
-}
-
-fn is_explicit_empty_activity_value(value: &Value) -> bool {
-    match value {
-        Value::Null => true,
-        Value::Array(values) => {
-            values.is_empty() || values.iter().all(is_explicit_empty_activity_value)
-        }
-        Value::String(text) => text.trim().is_empty(),
-        Value::Object(object) => {
-            if let Some(text) = object.get("text") {
-                return is_explicit_empty_activity_value(text);
-            }
-            ["activities", "activity", "events", "items", "result"]
-                .iter()
-                .any(|key| {
-                    object
-                        .get(*key)
-                        .is_some_and(is_explicit_empty_activity_value)
-                })
-        }
-        _ => false,
-    }
-}
-
-fn collect_content_text(value: &Value, texts: &mut Vec<String>) {
-    match value {
-        Value::Object(object) => {
-            if let Some(text) = object.get("text").and_then(Value::as_str) {
-                texts.push(text.to_string());
-                return;
-            }
-            for child in object.values() {
-                collect_content_text(child, texts);
-            }
-        }
-        Value::Array(values) => {
-            for child in values {
-                collect_content_text(child, texts);
-            }
-        }
-        _ => {}
-    }
-}
-
-fn parse_drive_activity_line(line: &str, expected_file_id: &str) -> Option<ParsedDriveActivity> {
-    let line = line.trim().strip_prefix("- ").unwrap_or(line.trim());
-    let after_open = line.strip_prefix('[')?;
-    let (timestamp, rest) = after_open.split_once("] ")?;
-    let timestamp = parse_drive_activity_timestamp(timestamp)?;
-    let (action, rest) = rest.split_once(" by ")?;
-    let action = action.to_ascii_lowercase();
-    let action_type = if action.contains("comment") {
-        "comment"
-    } else if action.contains("edit") {
-        "edit"
-    } else {
-        return None;
-    };
-    let (actor, target) = rest.split_once(" on \"")?;
-    let (_, detail) = target.rsplit_once("\" (")?;
-    let reported_file_id = detail
-        .split("id: ")
-        .nth(1)?
-        .split([',', ')'])
-        .next()?
-        .trim();
-    let file_id = reported_file_id
-        .strip_prefix("items/")
-        .unwrap_or(reported_file_id);
-    if file_id != expected_file_id || !valid_drive_file_id(file_id) {
-        return None;
-    }
-    let (actor_display_name, actor_email) = parse_drive_actor(actor.trim());
-    Some(ParsedDriveActivity {
-        action_type: action_type.to_string(),
-        timestamp,
-        actor_display_name,
-        actor_email,
-    })
-}
-
-fn parse_drive_activity_timestamp(raw: &str) -> Option<String> {
-    let timestamp = DateTime::parse_from_rfc3339(raw)
-        .map(|timestamp| timestamp.with_timezone(&Utc))
-        .or_else(|_| {
-            NaiveDateTime::parse_from_str(raw, "%Y-%m-%d %H:%M:%S%.f")
-                .map(|timestamp| timestamp.and_utc())
-        })
-        .ok()?;
-    Some(timestamp.to_rfc3339_opts(SecondsFormat::Millis, true))
-}
-
-fn parse_drive_actor(actor: &str) -> (Option<String>, Option<String>) {
-    let actor = actor.trim();
-    if let Some((name, email)) = actor
-        .strip_suffix(')')
-        .and_then(|value| value.rsplit_once(" ("))
-    {
-        if valid_actor_email(email) {
-            return (nonempty_actor_name(name), Some(email.to_string()));
-        }
-    }
-    if let Some((name, email)) = actor
-        .strip_suffix('>')
-        .and_then(|value| value.rsplit_once(" <"))
-    {
-        if valid_actor_email(email) {
-            return (nonempty_actor_name(name), Some(email.to_string()));
-        }
-    }
-    if valid_actor_email(actor) {
-        return (None, Some(actor.to_string()));
-    }
-    (nonempty_actor_name(actor), None)
-}
-
-fn nonempty_actor_name(name: &str) -> Option<String> {
-    let name = name.trim();
-    (!name.is_empty() && name.len() <= 256 && !name.chars().any(char::is_control))
-        .then(|| name.to_string())
-}
-
-fn valid_actor_email(email: &str) -> bool {
-    email.len() <= 254
-        && email.contains('@')
-        && !email
-            .chars()
-            .any(|character| character.is_whitespace() || character.is_control())
-}
-
-fn parse_calendar_links(output: &[u8]) -> Result<Vec<CollectionDiscoveredLink>, String> {
-    let response: CalendarToolResponse = serde_json::from_slice(output)
-        .map_err(|error| format!("invalid Google Calendar response: {error}"))?;
-    let attachments = response
-        .result
-        .map_or(response.attachments, |result| result.attachments);
-    let mut links = Vec::new();
-    for attachment in attachments {
-        if attachment.file_url != attachment.file_url.trim()
-            || attachment.file_url.chars().any(char::is_control)
-        {
-            continue;
-        }
-        let Ok(url) = url::Url::parse(&attachment.file_url) else {
-            continue;
-        };
-        if !matches!(url.scheme(), "http" | "https")
-            || url.host_str().is_none()
-            || !url.username().is_empty()
-            || url.password().is_some()
-            || google_drive_file_id(url.as_str()).is_none()
-        {
-            continue;
-        }
-        links.push(CollectionDiscoveredLink {
-            url: url.to_string(),
-            label: if attachment.title.trim().is_empty() {
-                url.host_str().unwrap_or_default().to_string()
-            } else {
-                attachment.title.trim().to_string()
-            },
-            kind: "document".to_string(),
-        });
-    }
-    links.sort_by(|left, right| left.url.cmp(&right.url));
-    links.dedup_by(|left, right| left.url == right.url);
-    Ok(links)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn command_ids_are_validated_before_store_access() {
-        assert!(parse_uuid("not-a-uuid", "collection").is_err());
-        assert!(parse_uuid("9a1657ac-f7aa-5db0-b632-d8bbeb6dfb50", "collection").is_ok());
-    }
-
-    #[test]
-    fn add_member_input_accepts_desktop_thread_payload() {
-        let input: AddCollectionMemberInput = serde_json::from_value(serde_json::json!({
-            "relay_url": "wss://buzz.block.builderlab.xyz",
-            "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
-            "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
-            "reference": {
-                "type": "thread",
-                "channel_id": "7f4a6441-4028-4cf5-8872-de456856d68e",
-                "root_event_id": "b016509b88c9c1cdc615f7101b779104a3101758f54e6a48a10a2e51843ff358"
-            },
-            "label": "Thread: production payload"
-        }))
-        .expect("desktop thread payload should deserialize");
-
-        assert!(matches!(
-            input.reference,
-            CollectionReference::Thread { .. }
-        ));
-    }
-
-    #[test]
-    fn icon_inputs_accept_create_set_and_clear_payloads() {
-        let create: CreateCollectionInput = serde_json::from_value(serde_json::json!({
-            "relay_url": "wss://buzz.block.builderlab.xyz",
-            "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
-            "name": "Bird Voice",
-            "description": null,
-            "icon": "🐦"
-        }))
-        .expect("create icon payload");
-        assert_eq!(create.icon.as_deref(), Some("🐦"));
-
-        let set: SetCollectionIconInput = serde_json::from_value(serde_json::json!({
-            "relay_url": "wss://buzz.block.builderlab.xyz",
-            "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
-            "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
-            "icon": "🎧"
-        }))
-        .expect("set icon payload");
-        assert_eq!(set.icon.as_deref(), Some("🎧"));
-
-        let clear: SetCollectionIconInput = serde_json::from_value(serde_json::json!({
-            "relay_url": "wss://buzz.block.builderlab.xyz",
-            "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
-            "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
-            "icon": null
-        }))
-        .expect("clear icon payload");
-        assert_eq!(clear.icon, None);
-    }
-
-    #[test]
-    fn rename_input_accepts_desktop_payload() {
-        let input: SetCollectionNameInput = serde_json::from_value(serde_json::json!({
-            "relay_url": "wss://buzz.block.builderlab.xyz",
-            "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
-            "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
-            "name": "Berd Voice"
-        }))
-        .expect("rename payload");
-        assert_eq!(input.name, "Berd Voice");
-    }
-
-    #[test]
-    fn calendar_discovery_only_accepts_google_event_links() {
-        assert!(validate_google_calendar_event_url(
-            "https://www.google.com/calendar/event?eid=abc123&ctz=UTC"
-        )
-        .is_ok());
-        assert!(
-            validate_google_calendar_event_url("https://example.com/calendar/event?eid=abc")
-                .is_err()
-        );
-        assert!(
-            validate_google_calendar_event_url("https://www.google.com/calendar/event").is_err()
-        );
-        assert!(validate_google_calendar_event_url(
-            "https://attacker@example.com/calendar/event?eid=abc"
-        )
-        .is_err());
-        assert!(validate_google_calendar_event_url(
-            "https://www.google.com:444/calendar/event?eid=abc"
-        )
-        .is_err());
-        assert!(validate_google_calendar_event_url(
-            "https://www.google.com/calendar/event?eid=abc#fragment"
-        )
-        .is_err());
-        assert!(validate_google_calendar_event_url(
-            "https://www.google.com/calendar/event?eid=abc&eid=second"
-        )
-        .is_err());
-    }
-
-    #[test]
-    fn calendar_discovery_returns_document_links_without_persisting_them() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        let output = serde_json::json!({
-            "result": {
-                "attachments": [
-                    {"fileUrl": format!("https://docs.google.com/document/d/{file_id}/edit"), "title": "Notes by Gemini"},
-                    {"fileUrl": "file:///tmp/private", "title": "Local file"},
-                    {"fileUrl": "https://user:secret@example.com/private", "title": "Credentials"},
-                    {"fileUrl": "https://example.com/meeting-notes.pdf", "title": "Arbitrary PDF"},
-                    {"fileUrl": "https://docs.google.com/document/d/too-short/edit", "title": "Malformed Drive ID"},
-                    {"fileUrl": format!("https://docs.google.com/document/d/{file_id}/edit"), "title": "Duplicate"}
-                ]
-            }
-        });
-        let links = parse_calendar_links(output.to_string().as_bytes()).expect("calendar links");
-        assert_eq!(
-            links,
-            vec![CollectionDiscoveredLink {
-                url: format!("https://docs.google.com/document/d/{file_id}/edit"),
-                label: "Notes by Gemini".to_string(),
-                kind: "document".to_string(),
-            }]
-        );
-    }
-
-    #[test]
-    fn calendar_discovery_accepts_direct_event_json() {
-        let drive_file_id = "1DriveFileAttachmentId_123456789";
-        let docs_file_id = "1DocsFileAttachmentId_1234567890";
-        let output = serde_json::json!({
-            "attachments": [
-                {"fileUrl": format!("https://drive.google.com/file/d/{drive_file_id}/view"), "title": " Drive file "},
-                {"fileUrl": "javascript:alert(1)", "title": "Unsafe"},
-                {"fileUrl": format!("https://docs.google.com/document/d/{docs_file_id}/edit"), "title": ""},
-                {"fileUrl": "https://example.com/no-title", "title": "Website"}
-            ]
-        });
-        let links = parse_calendar_links(output.to_string().as_bytes()).expect("calendar links");
-        assert_eq!(links.len(), 2);
-        assert_eq!(links[0].label, "docs.google.com");
-        assert_eq!(links[1].label, "Drive file");
-    }
-
-    #[test]
-    fn drive_file_ids_only_come_from_strict_attachment_urls() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        assert_eq!(
-            google_drive_file_id(&format!(
-                "https://docs.google.com/document/d/{file_id}/edit"
-            )),
-            Some(file_id.to_string())
-        );
-        assert_eq!(
-            google_drive_file_id(&format!("https://drive.google.com/file/d/{file_id}/view")),
-            Some(file_id.to_string())
-        );
-        assert_eq!(
-            google_drive_file_id(&format!("https://drive.google.com/open?id={file_id}")),
-            Some(file_id.to_string())
-        );
-        assert!(google_drive_file_id(&format!(
-            "https://docs.google.com.evil.example/document/d/{file_id}/edit"
-        ))
-        .is_none());
-        assert!(google_drive_file_id(&format!(
-            "https://user@docs.google.com/document/d/{file_id}/edit"
-        ))
-        .is_none());
-        assert!(google_drive_file_id(&format!(
-            "https://docs.google.com/spreadsheets/d/{file_id}/edit"
-        ))
-        .is_none());
-        assert!(google_drive_file_id("https://drive.google.com/file/d/too-short/view").is_none());
-    }
-
-    #[test]
-    fn drive_metadata_must_match_the_attached_google_doc() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        let output = serde_json::json!({
-            "content": [{"type": "text", "text": "metadata loaded"}],
-            "structuredContent": {
-                "id": file_id,
-                "name": "Launch notes",
-                "mimeType": "application/vnd.google-apps.document",
-                "webViewLink": format!("https://docs.google.com/document/d/{file_id}/edit")
-            }
-        });
-        let metadata =
-            parse_drive_metadata(output.to_string().as_bytes(), file_id).expect("metadata");
-        assert_eq!(metadata.title, "Launch notes");
-        assert_eq!(metadata.file_id, file_id);
-
-        assert!(
-            parse_drive_metadata(output.to_string().as_bytes(), "differentFileId12345").is_err()
-        );
-    }
-
-    #[test]
-    fn drive_metadata_accepts_formatted_raw_content() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        let output = serde_json::json!({
-            "content": [{
-                "type": "text",
-                "text": format!(
-                    "## File metadata\n- **ID:** `{file_id}`\n- **Name:** Launch notes\n- **MIME type:** application/vnd.google-apps.document\n- **Web view link:** https://docs.google.com/document/d/{file_id}/edit"
-                )
-            }]
-        });
-        let metadata =
-            parse_drive_metadata(output.to_string().as_bytes(), file_id).expect("metadata");
-        assert_eq!(metadata.title, "Launch notes");
-    }
-
-    #[test]
-    fn drive_activity_parses_realistic_edit_and_comment_output() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        let raw = serde_json::json!({
-            "content": [{
-                "text": {
-                    "text": format!(
-                        "- [2026-08-27T13:42:01Z] EDIT by Ada Lovelace (ada@example.com) on \"Launch notes\" (type: drive#file, id: {file_id})\n- [2026-08-27T14:05:03-04:00] COMMENT by Grace Hopper <grace@example.com> on \"Launch notes\" (type: drive#file, id: {file_id})\n- [2026-08-27T14:06:00Z] RENAME by Someone on \"Launch notes\" (type: drive#file, id: {file_id})\n- [2026-08-27T14:07:00Z] EDIT by Attacker on \"Other\" (type: drive#file, id: 1OtherValidatedFileId987654321)"
-                    )
-                }
-            }]
-        });
-        let activities =
-            parse_drive_activity(raw.to_string().as_bytes(), file_id).expect("activity");
-        assert_eq!(activities.len(), 2);
-        assert_eq!(activities[0].action_type, "comment");
-        assert_eq!(activities[0].timestamp, "2026-08-27T18:05:03.000Z");
-        assert_eq!(
-            activities[0].actor_display_name.as_deref(),
-            Some("Grace Hopper")
-        );
-        assert_eq!(
-            activities[0].actor_email.as_deref(),
-            Some("grace@example.com")
-        );
-        assert_eq!(activities[1].action_type, "edit");
-        assert_eq!(
-            activities[1].actor_display_name.as_deref(),
-            Some("Ada Lovelace")
-        );
-        assert_eq!(
-            activities[1].actor_email.as_deref(),
-            Some("ada@example.com")
-        );
-    }
-
-    #[test]
-    fn drive_activity_parses_live_naive_utc_timestamp_and_item_id() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        let raw = serde_json::json!({
-            "content": [{
-                "text": {
-                    "text": format!(
-                        "- [2026-08-27 18:09:30] EDIT by Ada Lovelace (ada@example.com) on \"Launch notes\" (type: drive#file, id: items/{file_id})\n- [2026-08-27 18:10:31] COMMENT by Grace Hopper on \"Launch notes\" (type: drive#file, id: items/{file_id})\n- [2026-08-27 18:11:32] EDIT by Wrong File on \"Other\" (type: drive#file, id: items/1OtherValidatedFileId987654321)"
-                    )
-                }
-            }],
-            "is_error": false
-        });
-        let activities =
-            parse_drive_activity(raw.to_string().as_bytes(), file_id).expect("live activity");
-        assert_eq!(activities.len(), 2);
-        assert_eq!(activities[0].action_type, "comment");
-        assert_eq!(activities[0].timestamp, "2026-08-27T18:10:31.000Z");
-        assert_eq!(activities[1].action_type, "edit");
-        assert_eq!(activities[1].timestamp, "2026-08-27T18:09:30.000Z");
-    }
-
-    #[test]
-    fn drive_activity_accepts_explicit_empty_structured_responses() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        for output in [
-            serde_json::json!({"content": [], "is_error": false}),
-            serde_json::json!({
-                "content": [{"text": {"text": ""}}],
-                "is_error": false
-            }),
-            serde_json::json!({
-                "content": [],
-                "structuredContent": {"activities": []},
-                "is_error": false
-            }),
-            serde_json::json!({
-                "content": [{"text": {"text": "No Drive activity found."}}],
-                "is_error": false
-            }),
-            serde_json::json!({
-                "content": [
-                    {"text": {"text": "No recent activity found."}},
-                    {"structured_content": {"data": {"result": "No recent activity found."}}}
-                ],
-                "is_error": false,
-                "structured_content_json": "{\"result\":\"No recent activity found.\"}"
-            }),
-            serde_json::json!({
-                "content": [{"text": {"text": "[]"}}],
-                "is_error": false
-            }),
-        ] {
-            assert!(parse_drive_activity(output.to_string().as_bytes(), file_id)
-                .expect("empty activity response")
-                .is_empty());
-        }
-    }
-
-    #[test]
-    fn drive_activity_rejects_malformed_nonempty_responses() {
-        let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
-        let output = serde_json::json!({
-            "content": [{"text": {"text": "unexpected nonempty response"}}],
-            "is_error": false
-        });
-        assert!(parse_drive_activity(output.to_string().as_bytes(), file_id).is_err());
-    }
-
-    #[test]
-    fn calendar_activity_serializes_provenance() {
-        let activity = CollectionCalendarActivity {
-            action_type: "comment".into(),
-            timestamp: "2026-08-27T18:05:03.000Z".into(),
-            actor_display_name: Some("Grace Hopper".into()),
-            actor_email: Some("grace@example.com".into()),
-            document_title: "Launch notes".into(),
-            document_url:
-                "https://docs.google.com/document/d/1AbCdEfGhIjKlMnOpQrStUvWxYz_123456/edit".into(),
-            document_file_id: "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456".into(),
-            source_calendar_url: "https://www.google.com/calendar/event?eid=calendar-source".into(),
-            source_attachment_url:
-                "https://drive.google.com/file/d/1AbCdEfGhIjKlMnOpQrStUvWxYz_123456/view".into(),
-        };
-        let value = serde_json::to_value(activity).expect("serialize activity");
-        assert_eq!(value["action_type"], "comment");
-        assert_eq!(
-            value["source_calendar_url"],
-            "https://www.google.com/calendar/event?eid=calendar-source"
-        );
-        assert!(value["source_attachment_url"]
-            .as_str()
-            .is_some_and(|url| url.contains("drive.google.com/file/d/")));
-    }
-
-    #[test]
-    fn drive_activity_window_is_bounded_by_valid_rfc3339_inputs() {
-        assert!(
-            validate_activity_window("2026-08-26T00:00:00Z", Some("2026-08-27T00:00:00Z")).is_ok()
-        );
-        assert!(validate_activity_window("yesterday", None).is_err());
-        assert!(
-            validate_activity_window("2026-08-27T00:00:00Z", Some("2026-08-26T00:00:00Z")).is_err()
-        );
-    }
-
-    #[tokio::test]
-    async fn calendar_tool_output_is_bounded() {
-        let error = read_bounded(&b"12345"[..], 4)
-            .await
-            .expect_err("oversized output should fail");
-        assert_eq!(error.kind(), std::io::ErrorKind::InvalidData);
-    }
-}
diff --git a/desktop/src-tauri/src/commands/collections/calendar.rs b/desktop/src-tauri/src/commands/collections/calendar.rs
new file mode 100644
index 0000000000..7e7a4f9f5c
--- /dev/null
+++ b/desktop/src-tauri/src/commands/collections/calendar.rs
@@ -0,0 +1,848 @@
+use std::{collections::HashSet, path::Path, process::Stdio, time::Duration};
+
+use chrono::{DateTime, NaiveDateTime, SecondsFormat, Utc};
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+use tokio::io::{AsyncRead, AsyncReadExt};
+use tokio::process::Command;
+
+const CALENDAR_DISCOVERY_TIMEOUT: Duration = Duration::from_secs(20);
+const CALENDAR_TOOL_TIMEOUT_SECS: &str = "15";
+const DRIVE_PROCESS_TIMEOUT: Duration = Duration::from_secs(12);
+const DRIVE_TOOL_TIMEOUT_SECS: &str = "10";
+const CALENDAR_ACTIVITY_TIMEOUT: Duration = Duration::from_secs(45);
+const MAX_ACTIVITY_DOCUMENTS: usize = 16;
+const MAX_CALENDAR_STDOUT_BYTES: usize = 1024 * 1024;
+const MAX_CALENDAR_STDERR_BYTES: usize = 64 * 1024;
+const CALENDAR_UNAVAILABLE: &str = "Optional Google Calendar discovery is unavailable";
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+pub struct CollectionDiscoveredLink {
+    pub url: String,
+    pub label: String,
+    pub kind: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+pub struct CollectionCalendarActivity {
+    pub action_type: String,
+    pub timestamp: String,
+    pub actor_display_name: Option<String>,
+    pub actor_email: Option<String>,
+    pub document_title: String,
+    pub document_url: String,
+    pub document_file_id: String,
+    pub source_calendar_url: String,
+    pub source_attachment_url: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+pub struct CollectionActivitySourceError {
+    pub source_url: String,
+    pub message: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+pub struct CollectionCalendarActivityResult {
+    pub activities: Vec<CollectionCalendarActivity>,
+    pub errors: Vec<CollectionActivitySourceError>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct DriveDocumentMetadata {
+    file_id: String,
+    title: String,
+    url: String,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct ParsedDriveActivity {
+    action_type: String,
+    timestamp: String,
+    actor_display_name: Option<String>,
+    actor_email: Option<String>,
+}
+
+#[derive(Debug, Deserialize)]
+struct CalendarToolResponse {
+    #[serde(default)]
+    result: Option<CalendarEventResult>,
+    #[serde(default)]
+    attachments: Vec<CalendarAttachment>,
+}
+
+#[derive(Debug, Deserialize)]
+struct CalendarEventResult {
+    #[serde(default)]
+    attachments: Vec<CalendarAttachment>,
+}
+
+#[derive(Debug, Deserialize)]
+struct CalendarAttachment {
+    #[serde(rename = "fileUrl")]
+    file_url: String,
+    #[serde(default)]
+    title: String,
+}
+
+/// Discover current document attachments for a linked Google Calendar event.
+///
+/// Collections keep the calendar event as the explicit membership edge. This
+/// optional local resolver reads the user's already-connected Calendar account
+/// and returns ephemeral children; it never writes those children to SQLite.
+#[tauri::command]
+pub async fn discover_collection_calendar_links(
+    url: String,
+) -> Result<Vec<CollectionDiscoveredLink>, String> {
+    validate_google_calendar_event_url(&url)?;
+    let sq_path = crate::managed_agents::resolve_command("sq")
+        .ok_or_else(|| format!("{CALENDAR_UNAVAILABLE}: `sq` was not found on this device"))?;
+
+    fetch_calendar_links(&sq_path, &url).await
+}
+
+/// Discover ephemeral edit and comment activity for Google Drive documents
+/// attached to an explicit Google Calendar event.
+#[tauri::command]
+pub async fn discover_collection_calendar_activity(
+    calendar_url: String,
+    start_time: String,
+    end_time: Option<String>,
+) -> Result<CollectionCalendarActivityResult, String> {
+    validate_google_calendar_event_url(&calendar_url)?;
+    validate_activity_window(&start_time, end_time.as_deref())?;
+    let sq_path = crate::managed_agents::resolve_command("sq").ok_or_else(|| {
+        format!(
+            "Optional Google Calendar activity discovery is unavailable for {calendar_url}: `sq` was not found on this device"
+        )
+    })?;
+
+    tokio::time::timeout(
+        CALENDAR_ACTIVITY_TIMEOUT,
+        discover_calendar_activity(&sq_path, &calendar_url, &start_time, end_time.as_deref()),
+    )
+    .await
+    .map_err(|_| {
+        format!(
+            "Optional Google Calendar activity discovery is unavailable for {calendar_url}: lookup timed out"
+        )
+    })?
+}
+
+async fn fetch_calendar_links(
+    sq_path: &Path,
+    url: &str,
+) -> Result<Vec<CollectionDiscoveredLink>, String> {
+    let args = [
+        "agent-tools",
+        "google-calendar",
+        "get-calendar-event",
+        "--event-id",
+        url,
+        "--calendar-id",
+        "primary",
+        "--output",
+        "json",
+        "--timeout",
+        CALENDAR_TOOL_TIMEOUT_SECS,
+    ];
+    let stdout = run_sq_command(
+        sq_path,
+        &args,
+        CALENDAR_DISCOVERY_TIMEOUT,
+        CALENDAR_UNAVAILABLE,
+    )
+    .await?;
+    parse_calendar_links(&stdout).map_err(|error| format!("{CALENDAR_UNAVAILABLE}: {error}"))
+}
+
+async fn discover_calendar_activity(
+    sq_path: &Path,
+    calendar_url: &str,
+    start_time: &str,
+    end_time: Option<&str>,
+) -> Result<CollectionCalendarActivityResult, String> {
+    let links = fetch_calendar_links(sq_path, calendar_url)
+        .await
+        .map_err(|error| {
+            format!(
+                "Optional Google Calendar activity discovery is unavailable for {calendar_url}: {error}"
+            )
+        })?;
+    let mut documents = Vec::new();
+    let mut seen_file_ids = HashSet::new();
+    for link in links {
+        let Some(file_id) = google_drive_file_id(&link.url) else {
+            continue;
+        };
+        if seen_file_ids.insert(file_id.clone()) {
+            documents.push((file_id, link.url, link.label));
+        }
+    }
+
+    let mut result = CollectionCalendarActivityResult {
+        activities: Vec::new(),
+        errors: Vec::new(),
+    };
+    if documents.len() > MAX_ACTIVITY_DOCUMENTS {
+        result.errors.push(CollectionActivitySourceError {
+            source_url: calendar_url.to_string(),
+            message: format!(
+                "Only the first {MAX_ACTIVITY_DOCUMENTS} attached Drive documents were checked"
+            ),
+        });
+        documents.truncate(MAX_ACTIVITY_DOCUMENTS);
+    }
+
+    for (file_id, attachment_url, attachment_label) in documents {
+        let metadata = match fetch_drive_metadata(sq_path, &file_id).await {
+            Ok(metadata) => metadata,
+            Err(message) => {
+                result.errors.push(CollectionActivitySourceError {
+                    source_url: attachment_url,
+                    message: format!("{attachment_label} ({file_id}): {message}"),
+                });
+                continue;
+            }
+        };
+        let activities = match fetch_drive_activity(sq_path, &file_id, start_time, end_time).await {
+            Ok(activities) => activities,
+            Err(message) => {
+                result.errors.push(CollectionActivitySourceError {
+                    source_url: attachment_url,
+                    message: format!("{} ({file_id}): {message}", metadata.title),
+                });
+                continue;
+            }
+        };
+        result
+            .activities
+            .extend(
+                activities
+                    .into_iter()
+                    .map(|activity| CollectionCalendarActivity {
+                        action_type: activity.action_type,
+                        timestamp: activity.timestamp,
+                        actor_display_name: activity.actor_display_name,
+                        actor_email: activity.actor_email,
+                        document_title: metadata.title.clone(),
+                        document_url: metadata.url.clone(),
+                        document_file_id: metadata.file_id.clone(),
+                        source_calendar_url: calendar_url.to_string(),
+                        source_attachment_url: attachment_url.clone(),
+                    }),
+            );
+    }
+
+    result.activities.sort_by(|left, right| {
+        right
+            .timestamp
+            .cmp(&left.timestamp)
+            .then_with(|| left.document_file_id.cmp(&right.document_file_id))
+            .then_with(|| left.action_type.cmp(&right.action_type))
+    });
+    result.activities.dedup_by(|left, right| {
+        left.document_file_id == right.document_file_id
+            && left.action_type == right.action_type
+            && left.timestamp == right.timestamp
+            && left.actor_email == right.actor_email
+            && left.actor_display_name == right.actor_display_name
+    });
+    Ok(result)
+}
+
+async fn fetch_drive_metadata(
+    sq_path: &Path,
+    file_id: &str,
+) -> Result<DriveDocumentMetadata, String> {
+    let args = [
+        "agent-tools",
+        "google-drive",
+        "get-file-metadata",
+        "--file-id-or-url",
+        file_id,
+        "--raw",
+        "--timeout",
+        DRIVE_TOOL_TIMEOUT_SECS,
+    ];
+    let unavailable = "Optional Google Drive metadata is unavailable";
+    let output = run_sq_command(sq_path, &args, DRIVE_PROCESS_TIMEOUT, unavailable).await?;
+    parse_drive_metadata(&output, file_id).map_err(|error| format!("{unavailable}: {error}"))
+}
+
+async fn fetch_drive_activity(
+    sq_path: &Path,
+    file_id: &str,
+    start_time: &str,
+    end_time: Option<&str>,
+) -> Result<Vec<ParsedDriveActivity>, String> {
+    let mut args = vec![
+        "agent-tools",
+        "google-drive",
+        "activity",
+        "--start-time",
+        start_time,
+    ];
+    if let Some(end_time) = end_time {
+        args.extend(["--end-time", end_time]);
+    }
+    args.extend([
+        "--item-id",
+        file_id,
+        "--activity-type",
+        "edit",
+        "comment",
+        "--lookup-people",
+        "--raw",
+        "--timeout",
+        DRIVE_TOOL_TIMEOUT_SECS,
+    ]);
+    let unavailable = "Optional Google Drive activity is unavailable";
+    let output = run_sq_command(sq_path, &args, DRIVE_PROCESS_TIMEOUT, unavailable).await?;
+    parse_drive_activity(&output, file_id).map_err(|error| format!("{unavailable}: {error}"))
+}
+
+async fn run_sq_command(
+    sq_path: &Path,
+    args: &[&str],
+    process_timeout: Duration,
+    unavailable: &str,
+) -> Result<Vec<u8>, String> {
+    let mut command = Command::new(sq_path);
+    command
+        .args(args)
+        .stdin(Stdio::null())
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .kill_on_drop(true);
+
+    let mut child = command
+        .spawn()
+        .map_err(|error| format!("{unavailable}: failed to start `sq`: {error}"))?;
+    let stdout = child
+        .stdout
+        .take()
+        .ok_or_else(|| format!("{unavailable}: failed to capture `sq` output"))?;
+    let stderr = child
+        .stderr
+        .take()
+        .ok_or_else(|| format!("{unavailable}: failed to capture `sq` errors"))?;
+
+    let (status, stdout, stderr) = tokio::time::timeout(process_timeout, async move {
+        let (stdout, stderr, status) = tokio::join!(
+            read_bounded(stdout, MAX_CALENDAR_STDOUT_BYTES),
+            read_bounded(stderr, MAX_CALENDAR_STDERR_BYTES),
+            child.wait(),
+        );
+        Ok::<_, std::io::Error>((status?, stdout?, stderr?))
+    })
+    .await
+    .map_err(|_| format!("{unavailable}: lookup timed out"))?
+    .map_err(|error| format!("{unavailable}: failed while running `sq`: {error}"))?;
+    if !status.success() {
+        return Err(format!(
+            "{unavailable}: {}",
+            first_safe_line(&stderr).unwrap_or("tool lookup failed")
+        ));
+    }
+    Ok(stdout)
+}
+
+async fn read_bounded(
+    reader: impl AsyncRead + Unpin,
+    max_bytes: usize,
+) -> Result<Vec<u8>, std::io::Error> {
+    let mut bytes = Vec::new();
+    reader
+        .take((max_bytes + 1) as u64)
+        .read_to_end(&mut bytes)
+        .await?;
+    if bytes.len() > max_bytes {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "tool response exceeded the size limit",
+        ));
+    }
+    Ok(bytes)
+}
+
+fn first_safe_line(stderr: &[u8]) -> Option<&str> {
+    std::str::from_utf8(stderr)
+        .ok()?
+        .lines()
+        .map(str::trim)
+        .find(|line| !line.is_empty() && !line.chars().any(char::is_control))
+}
+
+fn validate_google_calendar_event_url(raw: &str) -> Result<(), String> {
+    if raw != raw.trim() || raw.len() > 8 * 1024 || raw.chars().any(char::is_control) {
+        return Err("invalid Google Calendar event URL".to_string());
+    }
+    let url = url::Url::parse(raw).map_err(|_| "invalid Google Calendar event URL".to_string())?;
+    let is_google_host = matches!(
+        url.host_str(),
+        Some("www.google.com" | "calendar.google.com")
+    );
+    let event_ids = url
+        .query_pairs()
+        .filter(|(key, _)| key == "eid")
+        .collect::<Vec<_>>();
+    if url.scheme() != "https"
+        || !is_google_host
+        || !url.username().is_empty()
+        || url.password().is_some()
+        || url.port().is_some()
+        || url.path() != "/calendar/event"
+        || url.fragment().is_some()
+        || event_ids.len() != 1
+        || event_ids[0].1.is_empty()
+        || event_ids[0].1.chars().any(char::is_control)
+    {
+        return Err("URL is not a supported Google Calendar event".to_string());
+    }
+    Ok(())
+}
+
+fn validate_activity_window(start_time: &str, end_time: Option<&str>) -> Result<(), String> {
+    let start = DateTime::parse_from_rfc3339(start_time)
+        .map_err(|_| "invalid Drive activity start time; expected RFC 3339".to_string())?;
+    if let Some(end_time) = end_time {
+        let end = DateTime::parse_from_rfc3339(end_time)
+            .map_err(|_| "invalid Drive activity end time; expected RFC 3339".to_string())?;
+        if end <= start {
+            return Err("Drive activity end time must be after start time".to_string());
+        }
+    }
+    Ok(())
+}
+
+fn google_drive_file_id(raw: &str) -> Option<String> {
+    if raw != raw.trim() || raw.len() > 8 * 1024 || raw.chars().any(char::is_control) {
+        return None;
+    }
+    let url = url::Url::parse(raw).ok()?;
+    if url.scheme() != "https"
+        || !url.username().is_empty()
+        || url.password().is_some()
+        || url.port().is_some()
+        || url.fragment().is_some()
+    {
+        return None;
+    }
+    let host = url.host_str()?;
+    let segments = url.path_segments()?.collect::<Vec<_>>();
+    let candidate = match host {
+        "docs.google.com"
+            if segments.first() == Some(&"document") && segments.get(1) == Some(&"d") =>
+        {
+            segments.get(2).copied()
+        }
+        "drive.google.com"
+            if segments.first() == Some(&"file") && segments.get(1) == Some(&"d") =>
+        {
+            segments.get(2).copied()
+        }
+        "drive.google.com" if url.path() == "/open" => {
+            let ids = url
+                .query_pairs()
+                .filter(|(key, _)| key == "id")
+                .map(|(_, value)| value.into_owned())
+                .collect::<Vec<_>>();
+            if ids.len() == 1 {
+                return valid_drive_file_id(&ids[0]).then(|| ids[0].clone());
+            }
+            None
+        }
+        _ => None,
+    }?;
+    valid_drive_file_id(candidate).then(|| candidate.to_string())
+}
+
+fn valid_drive_file_id(candidate: &str) -> bool {
+    (10..=128).contains(&candidate.len())
+        && candidate
+            .bytes()
+            .all(|byte| byte.is_ascii_alphanumeric() || matches!(byte, b'_' | b'-'))
+}
+
+fn parse_drive_metadata(
+    output: &[u8],
+    expected_file_id: &str,
+) -> Result<DriveDocumentMetadata, String> {
+    let value: Value = serde_json::from_slice(output)
+        .map_err(|error| format!("invalid Drive metadata response: {error}"))?;
+    if let Some(metadata) = find_drive_metadata(&value, expected_file_id) {
+        return Ok(metadata);
+    }
+    let mut texts = Vec::new();
+    collect_content_text(&value, &mut texts);
+    texts
+        .iter()
+        .find_map(|text| parse_drive_metadata_text(text, expected_file_id))
+        .ok_or_else(|| "metadata did not identify the attached Google document".to_string())
+}
+
+fn find_drive_metadata(value: &Value, expected_file_id: &str) -> Option<DriveDocumentMetadata> {
+    match value {
+        Value::Object(object) => {
+            let file_id = ["id", "fileId", "file_id"]
+                .iter()
+                .find_map(|key| object.get(*key).and_then(Value::as_str));
+            let mime_type = ["mimeType", "mime_type"]
+                .iter()
+                .find_map(|key| object.get(*key).and_then(Value::as_str));
+            let title = ["name", "title"]
+                .iter()
+                .find_map(|key| object.get(*key).and_then(Value::as_str));
+            let document_url = ["webViewLink", "web_view_link", "url"]
+                .iter()
+                .find_map(|key| object.get(*key).and_then(Value::as_str));
+            if file_id == Some(expected_file_id)
+                && mime_type == Some("application/vnd.google-apps.document")
+            {
+                let title = title?.trim();
+                let document_url = document_url?.trim();
+                if !title.is_empty()
+                    && !title.chars().any(char::is_control)
+                    && google_drive_file_id(document_url).as_deref() == Some(expected_file_id)
+                {
+                    return Some(DriveDocumentMetadata {
+                        file_id: expected_file_id.to_string(),
+                        title: title.to_string(),
+                        url: document_url.to_string(),
+                    });
+                }
+            }
+            for child in object.values() {
+                if let Some(metadata) = find_drive_metadata(child, expected_file_id) {
+                    return Some(metadata);
+                }
+            }
+            None
+        }
+        Value::Array(values) => values
+            .iter()
+            .find_map(|child| find_drive_metadata(child, expected_file_id)),
+        Value::String(text) => parse_embedded_json(text)
+            .as_ref()
+            .and_then(|embedded| find_drive_metadata(embedded, expected_file_id)),
+        _ => None,
+    }
+}
+
+fn parse_embedded_json(text: &str) -> Option<Value> {
+    let trimmed = text.trim();
+    let trimmed = trimmed
+        .strip_prefix("```json")
+        .or_else(|| trimmed.strip_prefix("```"))
+        .unwrap_or(trimmed)
+        .strip_suffix("```")
+        .unwrap_or(trimmed)
+        .trim();
+    serde_json::from_str(trimmed).ok()
+}
+
+fn parse_drive_metadata_text(text: &str, expected_file_id: &str) -> Option<DriveDocumentMetadata> {
+    let mut file_id = None;
+    let mut title = None;
+    let mut mime_type = None;
+    let mut document_url = None;
+    for line in text.lines() {
+        let line = line.trim().trim_start_matches(['-', '*', '#']).trim();
+        let Some((key, value)) = line.split_once(':') else {
+            continue;
+        };
+        let key = key
+            .trim_matches(|character: char| {
+                matches!(character, '*' | '`') || character.is_whitespace()
+            })
+            .to_ascii_lowercase();
+        let value = value.trim_matches(|character: char| {
+            matches!(character, '*' | '`') || character.is_whitespace()
+        });
+        match key.as_str() {
+            "id" | "file id" => file_id = Some(value),
+            "name" | "title" => title = Some(value),
+            "mime type" | "mimetype" => mime_type = Some(value),
+            "web view link" | "webviewlink" | "url" => document_url = Some(value),
+            _ => {}
+        }
+    }
+    if file_id != Some(expected_file_id)
+        || mime_type != Some("application/vnd.google-apps.document")
+    {
+        return None;
+    }
+    let title = title?;
+    let document_url = document_url?;
+    if title.is_empty()
+        || title.chars().any(char::is_control)
+        || google_drive_file_id(document_url).as_deref() != Some(expected_file_id)
+    {
+        return None;
+    }
+    Some(DriveDocumentMetadata {
+        file_id: expected_file_id.to_string(),
+        title: title.to_string(),
+        url: document_url.to_string(),
+    })
+}
+
+fn parse_drive_activity(
+    output: &[u8],
+    expected_file_id: &str,
+) -> Result<Vec<ParsedDriveActivity>, String> {
+    let Some(text) = drive_activity_text(output)? else {
+        return Ok(Vec::new());
+    };
+    let mut activities = text
+        .lines()
+        .filter_map(|line| parse_drive_activity_line(line, expected_file_id))
+        .collect::<Vec<_>>();
+    activities.sort_by(|left, right| right.timestamp.cmp(&left.timestamp));
+    activities.dedup();
+    if activities.is_empty() && !is_empty_activity_text(&text) {
+        return Err(
+            "Drive activity response contained no recognized edit or comment events".into(),
+        );
+    }
+    Ok(activities)
+}
+
+fn is_empty_activity_text(text: &str) -> bool {
+    let text = text.trim();
+    if text.is_empty() {
+        return true;
+    }
+    let lowercase = text.to_ascii_lowercase();
+    if lowercase.contains("no activity")
+        || lowercase.contains("no recent activity")
+        || lowercase.contains("no drive activity")
+        || lowercase.contains("no matching activity")
+        || lowercase.contains("no events")
+    {
+        return true;
+    }
+    parse_embedded_json(text)
+        .as_ref()
+        .is_some_and(is_explicit_empty_activity_value)
+}
+
+fn drive_activity_text(output: &[u8]) -> Result<Option<String>, String> {
+    let raw = std::str::from_utf8(output)
+        .map_err(|_| "Drive activity response was not UTF-8".to_string())?;
+    if raw.trim().is_empty() {
+        return Ok(None);
+    }
+    let Ok(value) = serde_json::from_str::<Value>(raw) else {
+        return Ok(Some(raw.to_string()));
+    };
+    let mut texts = Vec::new();
+    collect_content_text(&value, &mut texts);
+    texts.retain(|text| !text.trim().is_empty());
+    if texts.is_empty() && is_explicit_empty_activity_response(&value) {
+        return Ok(None);
+    }
+    if texts.is_empty() {
+        return Err("Drive activity response did not contain text content".into());
+    }
+    Ok(Some(texts.join("\n")))
+}
+
+fn is_explicit_empty_activity_response(value: &Value) -> bool {
+    match value {
+        Value::Object(object) => {
+            if object.get("is_error").and_then(Value::as_bool) == Some(true)
+                || object.get("isError").and_then(Value::as_bool) == Some(true)
+            {
+                return false;
+            }
+            [
+                "content",
+                "activities",
+                "activity",
+                "events",
+                "items",
+                "result",
+            ]
+            .iter()
+            .any(|key| {
+                object
+                    .get(*key)
+                    .is_some_and(is_explicit_empty_activity_value)
+            })
+        }
+        _ => false,
+    }
+}
+
+fn is_explicit_empty_activity_value(value: &Value) -> bool {
+    match value {
+        Value::Null => true,
+        Value::Array(values) => {
+            values.is_empty() || values.iter().all(is_explicit_empty_activity_value)
+        }
+        Value::String(text) => text.trim().is_empty(),
+        Value::Object(object) => {
+            if let Some(text) = object.get("text") {
+                return is_explicit_empty_activity_value(text);
+            }
+            ["activities", "activity", "events", "items", "result"]
+                .iter()
+                .any(|key| {
+                    object
+                        .get(*key)
+                        .is_some_and(is_explicit_empty_activity_value)
+                })
+        }
+        _ => false,
+    }
+}
+
+fn collect_content_text(value: &Value, texts: &mut Vec<String>) {
+    match value {
+        Value::Object(object) => {
+            if let Some(text) = object.get("text").and_then(Value::as_str) {
+                texts.push(text.to_string());
+                return;
+            }
+            for child in object.values() {
+                collect_content_text(child, texts);
+            }
+        }
+        Value::Array(values) => {
+            for child in values {
+                collect_content_text(child, texts);
+            }
+        }
+        _ => {}
+    }
+}
+
+fn parse_drive_activity_line(line: &str, expected_file_id: &str) -> Option<ParsedDriveActivity> {
+    let line = line.trim().strip_prefix("- ").unwrap_or(line.trim());
+    let after_open = line.strip_prefix('[')?;
+    let (timestamp, rest) = after_open.split_once("] ")?;
+    let timestamp = parse_drive_activity_timestamp(timestamp)?;
+    let (action, rest) = rest.split_once(" by ")?;
+    let action = action.to_ascii_lowercase();
+    let action_type = if action.contains("comment") {
+        "comment"
+    } else if action.contains("edit") {
+        "edit"
+    } else {
+        return None;
+    };
+    let (actor, target) = rest.split_once(" on \"")?;
+    let (_, detail) = target.rsplit_once("\" (")?;
+    let reported_file_id = detail
+        .split("id: ")
+        .nth(1)?
+        .split([',', ')'])
+        .next()?
+        .trim();
+    let file_id = reported_file_id
+        .strip_prefix("items/")
+        .unwrap_or(reported_file_id);
+    if file_id != expected_file_id || !valid_drive_file_id(file_id) {
+        return None;
+    }
+    let (actor_display_name, actor_email) = parse_drive_actor(actor.trim());
+    Some(ParsedDriveActivity {
+        action_type: action_type.to_string(),
+        timestamp,
+        actor_display_name,
+        actor_email,
+    })
+}
+
+fn parse_drive_activity_timestamp(raw: &str) -> Option<String> {
+    let timestamp = DateTime::parse_from_rfc3339(raw)
+        .map(|timestamp| timestamp.with_timezone(&Utc))
+        .or_else(|_| {
+            NaiveDateTime::parse_from_str(raw, "%Y-%m-%d %H:%M:%S%.f")
+                .map(|timestamp| timestamp.and_utc())
+        })
+        .ok()?;
+    Some(timestamp.to_rfc3339_opts(SecondsFormat::Millis, true))
+}
+
+fn parse_drive_actor(actor: &str) -> (Option<String>, Option<String>) {
+    let actor = actor.trim();
+    if let Some((name, email)) = actor
+        .strip_suffix(')')
+        .and_then(|value| value.rsplit_once(" ("))
+    {
+        if valid_actor_email(email) {
+            return (nonempty_actor_name(name), Some(email.to_string()));
+        }
+    }
+    if let Some((name, email)) = actor
+        .strip_suffix('>')
+        .and_then(|value| value.rsplit_once(" <"))
+    {
+        if valid_actor_email(email) {
+            return (nonempty_actor_name(name), Some(email.to_string()));
+        }
+    }
+    if valid_actor_email(actor) {
+        return (None, Some(actor.to_string()));
+    }
+    (nonempty_actor_name(actor), None)
+}
+
+fn nonempty_actor_name(name: &str) -> Option<String> {
+    let name = name.trim();
+    (!name.is_empty() && name.len() <= 256 && !name.chars().any(char::is_control))
+        .then(|| name.to_string())
+}
+
+fn valid_actor_email(email: &str) -> bool {
+    email.len() <= 254
+        && email.contains('@')
+        && !email
+            .chars()
+            .any(|character| character.is_whitespace() || character.is_control())
+}
+
+fn parse_calendar_links(output: &[u8]) -> Result<Vec<CollectionDiscoveredLink>, String> {
+    let response: CalendarToolResponse = serde_json::from_slice(output)
+        .map_err(|error| format!("invalid Google Calendar response: {error}"))?;
+    let attachments = response
+        .result
+        .map_or(response.attachments, |result| result.attachments);
+    let mut links = Vec::new();
+    for attachment in attachments {
+        if attachment.file_url != attachment.file_url.trim()
+            || attachment.file_url.chars().any(char::is_control)
+        {
+            continue;
+        }
+        let Ok(url) = url::Url::parse(&attachment.file_url) else {
+            continue;
+        };
+        if !matches!(url.scheme(), "http" | "https")
+            || url.host_str().is_none()
+            || !url.username().is_empty()
+            || url.password().is_some()
+            || google_drive_file_id(url.as_str()).is_none()
+        {
+            continue;
+        }
+        links.push(CollectionDiscoveredLink {
+            url: url.to_string(),
+            label: if attachment.title.trim().is_empty() {
+                url.host_str().unwrap_or_default().to_string()
+            } else {
+                attachment.title.trim().to_string()
+            },
+            kind: "document".to_string(),
+        });
+    }
+    links.sort_by(|left, right| left.url.cmp(&right.url));
+    links.dedup_by(|left, right| left.url == right.url);
+    Ok(links)
+}
+
+#[cfg(test)]
+mod tests;
diff --git a/desktop/src-tauri/src/commands/collections/calendar/tests.rs b/desktop/src-tauri/src/commands/collections/calendar/tests.rs
new file mode 100644
index 0000000000..ff2fcd3aa8
--- /dev/null
+++ b/desktop/src-tauri/src/commands/collections/calendar/tests.rs
@@ -0,0 +1,361 @@
+use super::super::{
+    parse_uuid, AddCollectionMemberInput, CreateCollectionInput, SetCollectionIconInput,
+    SetCollectionNameInput,
+};
+use super::*;
+use buzz_collections_pkg::CollectionReference;
+
+#[test]
+fn command_ids_are_validated_before_store_access() {
+    assert!(parse_uuid("not-a-uuid", "collection").is_err());
+    assert!(parse_uuid("9a1657ac-f7aa-5db0-b632-d8bbeb6dfb50", "collection").is_ok());
+}
+
+#[test]
+fn add_member_input_accepts_desktop_thread_payload() {
+    let input: AddCollectionMemberInput = serde_json::from_value(serde_json::json!({
+        "relay_url": "wss://buzz.block.builderlab.xyz",
+        "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
+        "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
+        "reference": {
+            "type": "thread",
+            "channel_id": "7f4a6441-4028-4cf5-8872-de456856d68e",
+            "root_event_id": "b016509b88c9c1cdc615f7101b779104a3101758f54e6a48a10a2e51843ff358"
+        },
+        "label": "Thread: production payload"
+    }))
+    .expect("desktop thread payload should deserialize");
+
+    assert!(matches!(
+        input.reference,
+        CollectionReference::Thread { .. }
+    ));
+}
+
+#[test]
+fn icon_inputs_accept_create_set_and_clear_payloads() {
+    let create: CreateCollectionInput = serde_json::from_value(serde_json::json!({
+        "relay_url": "wss://buzz.block.builderlab.xyz",
+        "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
+        "name": "Bird Voice",
+        "description": null,
+        "icon": "🐦"
+    }))
+    .expect("create icon payload");
+    assert_eq!(create.icon.as_deref(), Some("🐦"));
+
+    let set: SetCollectionIconInput = serde_json::from_value(serde_json::json!({
+        "relay_url": "wss://buzz.block.builderlab.xyz",
+        "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
+        "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
+        "icon": "🎧"
+    }))
+    .expect("set icon payload");
+    assert_eq!(set.icon.as_deref(), Some("🎧"));
+
+    let clear: SetCollectionIconInput = serde_json::from_value(serde_json::json!({
+        "relay_url": "wss://buzz.block.builderlab.xyz",
+        "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
+        "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
+        "icon": null
+    }))
+    .expect("clear icon payload");
+    assert_eq!(clear.icon, None);
+}
+
+#[test]
+fn rename_input_accepts_desktop_payload() {
+    let input: SetCollectionNameInput = serde_json::from_value(serde_json::json!({
+        "relay_url": "wss://buzz.block.builderlab.xyz",
+        "owner_pubkey": "67252b09c31a995daa63aada26569fbc6a3d12f573113f001ce7432f870da820",
+        "collection_id": "593a7412-49ee-4709-ac66-17f6e6288279",
+        "name": "Berd Voice"
+    }))
+    .expect("rename payload");
+    assert_eq!(input.name, "Berd Voice");
+}
+
+#[test]
+fn calendar_discovery_only_accepts_google_event_links() {
+    assert!(validate_google_calendar_event_url(
+        "https://www.google.com/calendar/event?eid=abc123&ctz=UTC"
+    )
+    .is_ok());
+    assert!(
+        validate_google_calendar_event_url("https://example.com/calendar/event?eid=abc").is_err()
+    );
+    assert!(validate_google_calendar_event_url("https://www.google.com/calendar/event").is_err());
+    assert!(validate_google_calendar_event_url(
+        "https://attacker@example.com/calendar/event?eid=abc"
+    )
+    .is_err());
+    assert!(validate_google_calendar_event_url(
+        "https://www.google.com:444/calendar/event?eid=abc"
+    )
+    .is_err());
+    assert!(validate_google_calendar_event_url(
+        "https://www.google.com/calendar/event?eid=abc#fragment"
+    )
+    .is_err());
+    assert!(validate_google_calendar_event_url(
+        "https://www.google.com/calendar/event?eid=abc&eid=second"
+    )
+    .is_err());
+}
+
+#[test]
+fn calendar_discovery_returns_document_links_without_persisting_them() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    let output = serde_json::json!({
+        "result": {
+            "attachments": [
+                {"fileUrl": format!("https://docs.google.com/document/d/{file_id}/edit"), "title": "Notes by Gemini"},
+                {"fileUrl": "file:///tmp/private", "title": "Local file"},
+                {"fileUrl": "https://user:secret@example.com/private", "title": "Credentials"},
+                {"fileUrl": "https://example.com/meeting-notes.pdf", "title": "Arbitrary PDF"},
+                {"fileUrl": "https://docs.google.com/document/d/too-short/edit", "title": "Malformed Drive ID"},
+                {"fileUrl": format!("https://docs.google.com/document/d/{file_id}/edit"), "title": "Duplicate"}
+            ]
+        }
+    });
+    let links = parse_calendar_links(output.to_string().as_bytes()).expect("calendar links");
+    assert_eq!(
+        links,
+        vec![CollectionDiscoveredLink {
+            url: format!("https://docs.google.com/document/d/{file_id}/edit"),
+            label: "Notes by Gemini".to_string(),
+            kind: "document".to_string(),
+        }]
+    );
+}
+
+#[test]
+fn calendar_discovery_accepts_direct_event_json() {
+    let drive_file_id = "1DriveFileAttachmentId_123456789";
+    let docs_file_id = "1DocsFileAttachmentId_1234567890";
+    let output = serde_json::json!({
+        "attachments": [
+            {"fileUrl": format!("https://drive.google.com/file/d/{drive_file_id}/view"), "title": " Drive file "},
+            {"fileUrl": "javascript:alert(1)", "title": "Unsafe"},
+            {"fileUrl": format!("https://docs.google.com/document/d/{docs_file_id}/edit"), "title": ""},
+            {"fileUrl": "https://example.com/no-title", "title": "Website"}
+        ]
+    });
+    let links = parse_calendar_links(output.to_string().as_bytes()).expect("calendar links");
+    assert_eq!(links.len(), 2);
+    assert_eq!(links[0].label, "docs.google.com");
+    assert_eq!(links[1].label, "Drive file");
+}
+
+#[test]
+fn drive_file_ids_only_come_from_strict_attachment_urls() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    assert_eq!(
+        google_drive_file_id(&format!(
+            "https://docs.google.com/document/d/{file_id}/edit"
+        )),
+        Some(file_id.to_string())
+    );
+    assert_eq!(
+        google_drive_file_id(&format!("https://drive.google.com/file/d/{file_id}/view")),
+        Some(file_id.to_string())
+    );
+    assert_eq!(
+        google_drive_file_id(&format!("https://drive.google.com/open?id={file_id}")),
+        Some(file_id.to_string())
+    );
+    assert!(google_drive_file_id(&format!(
+        "https://docs.google.com.evil.example/document/d/{file_id}/edit"
+    ))
+    .is_none());
+    assert!(google_drive_file_id(&format!(
+        "https://user@docs.google.com/document/d/{file_id}/edit"
+    ))
+    .is_none());
+    assert!(google_drive_file_id(&format!(
+        "https://docs.google.com/spreadsheets/d/{file_id}/edit"
+    ))
+    .is_none());
+    assert!(google_drive_file_id("https://drive.google.com/file/d/too-short/view").is_none());
+}
+
+#[test]
+fn drive_metadata_must_match_the_attached_google_doc() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    let output = serde_json::json!({
+        "content": [{"type": "text", "text": "metadata loaded"}],
+        "structuredContent": {
+            "id": file_id,
+            "name": "Launch notes",
+            "mimeType": "application/vnd.google-apps.document",
+            "webViewLink": format!("https://docs.google.com/document/d/{file_id}/edit")
+        }
+    });
+    let metadata = parse_drive_metadata(output.to_string().as_bytes(), file_id).expect("metadata");
+    assert_eq!(metadata.title, "Launch notes");
+    assert_eq!(metadata.file_id, file_id);
+
+    assert!(parse_drive_metadata(output.to_string().as_bytes(), "differentFileId12345").is_err());
+}
+
+#[test]
+fn drive_metadata_accepts_formatted_raw_content() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    let output = serde_json::json!({
+        "content": [{
+            "type": "text",
+            "text": format!(
+                "## File metadata\n- **ID:** `{file_id}`\n- **Name:** Launch notes\n- **MIME type:** application/vnd.google-apps.document\n- **Web view link:** https://docs.google.com/document/d/{file_id}/edit"
+            )
+        }]
+    });
+    let metadata = parse_drive_metadata(output.to_string().as_bytes(), file_id).expect("metadata");
+    assert_eq!(metadata.title, "Launch notes");
+}
+
+#[test]
+fn drive_activity_parses_realistic_edit_and_comment_output() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    let raw = serde_json::json!({
+        "content": [{
+            "text": {
+                "text": format!(
+                    "- [2026-08-27T13:42:01Z] EDIT by Ada Lovelace (ada@example.com) on \"Launch notes\" (type: drive#file, id: {file_id})\n- [2026-08-27T14:05:03-04:00] COMMENT by Grace Hopper <grace@example.com> on \"Launch notes\" (type: drive#file, id: {file_id})\n- [2026-08-27T14:06:00Z] RENAME by Someone on \"Launch notes\" (type: drive#file, id: {file_id})\n- [2026-08-27T14:07:00Z] EDIT by Attacker on \"Other\" (type: drive#file, id: 1OtherValidatedFileId987654321)"
+                )
+            }
+        }]
+    });
+    let activities = parse_drive_activity(raw.to_string().as_bytes(), file_id).expect("activity");
+    assert_eq!(activities.len(), 2);
+    assert_eq!(activities[0].action_type, "comment");
+    assert_eq!(activities[0].timestamp, "2026-08-27T18:05:03.000Z");
+    assert_eq!(
+        activities[0].actor_display_name.as_deref(),
+        Some("Grace Hopper")
+    );
+    assert_eq!(
+        activities[0].actor_email.as_deref(),
+        Some("grace@example.com")
+    );
+    assert_eq!(activities[1].action_type, "edit");
+    assert_eq!(
+        activities[1].actor_display_name.as_deref(),
+        Some("Ada Lovelace")
+    );
+    assert_eq!(
+        activities[1].actor_email.as_deref(),
+        Some("ada@example.com")
+    );
+}
+
+#[test]
+fn drive_activity_parses_live_naive_utc_timestamp_and_item_id() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    let raw = serde_json::json!({
+        "content": [{
+            "text": {
+                "text": format!(
+                    "- [2026-08-27 18:09:30] EDIT by Ada Lovelace (ada@example.com) on \"Launch notes\" (type: drive#file, id: items/{file_id})\n- [2026-08-27 18:10:31] COMMENT by Grace Hopper on \"Launch notes\" (type: drive#file, id: items/{file_id})\n- [2026-08-27 18:11:32] EDIT by Wrong File on \"Other\" (type: drive#file, id: items/1OtherValidatedFileId987654321)"
+                )
+            }
+        }],
+        "is_error": false
+    });
+    let activities =
+        parse_drive_activity(raw.to_string().as_bytes(), file_id).expect("live activity");
+    assert_eq!(activities.len(), 2);
+    assert_eq!(activities[0].action_type, "comment");
+    assert_eq!(activities[0].timestamp, "2026-08-27T18:10:31.000Z");
+    assert_eq!(activities[1].action_type, "edit");
+    assert_eq!(activities[1].timestamp, "2026-08-27T18:09:30.000Z");
+}
+
+#[test]
+fn drive_activity_accepts_explicit_empty_structured_responses() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    for output in [
+        serde_json::json!({"content": [], "is_error": false}),
+        serde_json::json!({
+            "content": [{"text": {"text": ""}}],
+            "is_error": false
+        }),
+        serde_json::json!({
+            "content": [],
+            "structuredContent": {"activities": []},
+            "is_error": false
+        }),
+        serde_json::json!({
+            "content": [{"text": {"text": "No Drive activity found."}}],
+            "is_error": false
+        }),
+        serde_json::json!({
+            "content": [
+                {"text": {"text": "No recent activity found."}},
+                {"structured_content": {"data": {"result": "No recent activity found."}}}
+            ],
+            "is_error": false,
+            "structured_content_json": "{\"result\":\"No recent activity found.\"}"
+        }),
+        serde_json::json!({
+            "content": [{"text": {"text": "[]"}}],
+            "is_error": false
+        }),
+    ] {
+        assert!(parse_drive_activity(output.to_string().as_bytes(), file_id)
+            .expect("empty activity response")
+            .is_empty());
+    }
+}
+
+#[test]
+fn drive_activity_rejects_malformed_nonempty_responses() {
+    let file_id = "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456";
+    let output = serde_json::json!({
+        "content": [{"text": {"text": "unexpected nonempty response"}}],
+        "is_error": false
+    });
+    assert!(parse_drive_activity(output.to_string().as_bytes(), file_id).is_err());
+}
+
+#[test]
+fn calendar_activity_serializes_provenance() {
+    let activity = CollectionCalendarActivity {
+        action_type: "comment".into(),
+        timestamp: "2026-08-27T18:05:03.000Z".into(),
+        actor_display_name: Some("Grace Hopper".into()),
+        actor_email: Some("grace@example.com".into()),
+        document_title: "Launch notes".into(),
+        document_url: "https://docs.google.com/document/d/1AbCdEfGhIjKlMnOpQrStUvWxYz_123456/edit"
+            .into(),
+        document_file_id: "1AbCdEfGhIjKlMnOpQrStUvWxYz_123456".into(),
+        source_calendar_url: "https://www.google.com/calendar/event?eid=calendar-source".into(),
+        source_attachment_url:
+            "https://drive.google.com/file/d/1AbCdEfGhIjKlMnOpQrStUvWxYz_123456/view".into(),
+    };
+    let value = serde_json::to_value(activity).expect("serialize activity");
+    assert_eq!(value["action_type"], "comment");
+    assert_eq!(
+        value["source_calendar_url"],
+        "https://www.google.com/calendar/event?eid=calendar-source"
+    );
+    assert!(value["source_attachment_url"]
+        .as_str()
+        .is_some_and(|url| url.contains("drive.google.com/file/d/")));
+}
+
+#[test]
+fn drive_activity_window_is_bounded_by_valid_rfc3339_inputs() {
+    assert!(validate_activity_window("2026-08-26T00:00:00Z", Some("2026-08-27T00:00:00Z")).is_ok());
+    assert!(validate_activity_window("yesterday", None).is_err());
+    assert!(
+        validate_activity_window("2026-08-27T00:00:00Z", Some("2026-08-26T00:00:00Z")).is_err()
+    );
+}
+
+#[tokio::test]
+async fn calendar_tool_output_is_bounded() {
+    let error = read_bounded(&b"12345"[..], 4)
+        .await
+        .expect_err("oversized output should fail");
+    assert_eq!(error.kind(), std::io::ErrorKind::InvalidData);
+}
diff --git a/desktop/src/features/collections/ui/CollectionDetailRows.tsx b/desktop/src/features/collections/ui/CollectionDetailRows.tsx
new file mode 100644
index 0000000000..f5fdbfbb90
--- /dev/null
+++ b/desktop/src/features/collections/ui/CollectionDetailRows.tsx
@@ -0,0 +1,322 @@
+import { openUrl } from "@tauri-apps/plugin-opener";
+import {
+  CalendarDays,
+  Ellipsis,
+  ExternalLink,
+  FileText,
+  GitBranch,
+  GitPullRequest,
+  Hash,
+  Link2,
+  ListTodo,
+  MessageSquare,
+  MessagesSquare,
+  StickyNote,
+} from "lucide-react";
+import { toast } from "sonner";
+
+import { Button } from "@/shared/ui/button";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/shared/ui/dropdown-menu";
+import { UserAvatar } from "@/shared/ui/UserAvatar";
+import type { DerivedCollectionActivity } from "../derivedLinks";
+import { collectionReferenceIdentity } from "../memberDisplay";
+import type { CollectionMember, CollectionReferenceType } from "../types";
+
+export function DerivedCollectionActivityRow({
+  activity,
+  actorAvatarUrl,
+  actorLabel,
+  onOpenMessage,
+  onRemoveSource,
+}: {
+  activity: DerivedCollectionActivity;
+  actorAvatarUrl?: string;
+  actorLabel?: string;
+  onOpenMessage: () => void;
+  onRemoveSource: () => Promise<void>;
+}) {
+  const isMessage = activity.activityType === "channel-message";
+  const isDerived = !isMessage || activity.derivedFromSource === true;
+  const isDocumentActivity =
+    activity.activityType === "document-edit" ||
+    activity.activityType === "document-comment";
+  const isPullRequest = activity.activityType === "github-pr";
+  const isPullRequestActivity = activity.activityType === "github-pr-activity";
+  const identity = isMessage
+    ? activity.eventId
+    : isDocumentActivity || isPullRequestActivity
+      ? `${activity.url}:${activity.activityType}:${activity.createdAt}`
+      : activity.url;
+  const timestamp = activity.createdAt
+    ? new Intl.DateTimeFormat(undefined, {
+        dateStyle: "medium",
+        timeStyle: "short",
+      }).format(new Date(activity.createdAt * 1_000))
+    : null;
+  const content = (
+    <div className="min-w-0 flex-1">
+      <div className="flex items-center gap-2">
+        <ActivityTypeGlyph activity={activity} />
+        {isDerived ? (
+          <span
+            className="text-muted-foreground"
+            title={`Derived from ${activity.provenanceLabel ?? "an explicit Collection source"}`}
+          >
+            <Link2
+              aria-label={`Derived from ${activity.provenanceLabel ?? "an explicit Collection source"}`}
+              className="h-3.5 w-3.5"
+            />
+          </span>
+        ) : null}
+        <span className="truncate text-sm font-medium">{activity.label}</span>
+      </div>
+      {isDocumentActivity ? (
+        <div className="mt-1 text-sm">
+          {activity.actorLabel}{" "}
+          {activity.activityType === "document-edit"
+            ? "edited"
+            : "commented on"}{" "}
+          <span className="font-medium">{activity.label}</span>
+          {timestamp ? ` · ${timestamp}` : null}
+        </div>
+      ) : isPullRequestActivity ? (
+        <div className="mt-1 text-sm">
+          {activity.actorLabel ?? "Unknown GitHub actor"}{" "}
+          {activity.kind.replace(/^PR /u, "")}
+          {activity.stateLabel ? ` · ${activity.stateLabel}` : null}
+          {timestamp ? ` · ${timestamp}` : null}
+        </div>
+      ) : isPullRequest ? (
+        <div className="mt-1 text-sm">
+          {activity.stateLabel ? (
+            <span className="font-medium capitalize">
+              {activity.stateLabel}
+            </span>
+          ) : (
+            "Mentioned PR"
+          )}
+          {activity.actorLabel ? ` by ${activity.actorLabel}` : null}
+          {timestamp ? ` · ${timestamp}` : null}
+        </div>
+      ) : isMessage ? (
+        <div className="mt-1 text-sm">
+          {actorLabel ?? "Unknown Buzz user"}
+          {timestamp ? ` · ${timestamp}` : null}
+        </div>
+      ) : timestamp ? (
+        <div className="mt-1 text-xs text-muted-foreground">{timestamp}</div>
+      ) : null}
+      {activity.provenanceLabel ? (
+        <div className="mt-1 text-xs text-muted-foreground">
+          From {activity.provenanceLabel}
+        </div>
+      ) : null}
+      {activity.url ? (
+        <div className="mt-1 truncate text-xs text-muted-foreground">
+          {activity.url}
+        </div>
+      ) : null}
+    </div>
+  );
+  return (
+    <div
+      className="group flex items-center gap-3 p-4"
+      data-testid={`collection-derived-${encodeURIComponent(identity ?? "activity")}`}
+    >
+      {actorLabel ? (
+        <UserAvatar
+          avatarUrl={actorAvatarUrl ?? null}
+          displayName={actorLabel}
+          size="sm"
+        />
+      ) : null}
+      {isMessage ? (
+        <button
+          className="min-w-0 flex-1 text-left hover:underline"
+          onClick={onOpenMessage}
+          type="button"
+        >
+          {content}
+        </button>
+      ) : (
+        content
+      )}
+      {!isMessage ? (
+        <Button
+          aria-label={`Open derived link ${activity.label}`}
+          onClick={() => {
+            void openUrl(activity.url).catch(() =>
+              toast.error("Failed to open link"),
+            );
+          }}
+          size="icon"
+          variant="ghost"
+        >
+          <ExternalLink className="h-4 w-4" />
+        </Button>
+      ) : null}
+      <CollectionRowActions
+        derived={isDerived}
+        label={activity.label}
+        onRemove={onRemoveSource}
+      />
+    </div>
+  );
+}
+
+function ActivityTypeGlyph({
+  activity,
+}: {
+  activity: DerivedCollectionActivity;
+}) {
+  const Icon =
+    activity.activityType === "github-pr" ||
+    activity.activityType === "github-pr-activity"
+      ? GitPullRequest
+      : activity.activityType === "calendar-document"
+        ? CalendarDays
+        : activity.activityType === "channel-message"
+          ? activity.kind === "thread"
+            ? MessagesSquare
+            : MessageSquare
+          : FileText;
+  return (
+    <Icon
+      aria-label={activity.kind}
+      className="h-4 w-4 shrink-0 text-muted-foreground"
+    />
+  );
+}
+
+export function CollectionMemberRow({
+  canOpen,
+  isRemoving,
+  member,
+  onOpen,
+  onRemove,
+}: {
+  canOpen: boolean;
+  isRemoving: boolean;
+  member: CollectionMember;
+  onOpen: () => void;
+  onRemove: () => Promise<void>;
+}) {
+  const identity = collectionReferenceIdentity(member.reference);
+  const label = member.label || identity;
+  const content = (
+    <div className="flex items-center gap-2">
+      <SourceTypeGlyph type={member.reference.type} />
+      <span className="truncate text-sm font-medium">{label}</span>
+      {member.reference.type === "external" ? (
+        <span className="rounded bg-muted px-2 py-0.5 text-xs text-muted-foreground">
+          {new URL(member.reference.url).hostname}
+        </span>
+      ) : null}
+    </div>
+  );
+
+  return (
+    <div
+      className="group flex items-center gap-3 p-4"
+      data-testid={`collection-member-${member.id}`}
+    >
+      <div className="min-w-0 flex-1">
+        {canOpen && member.reference.type !== "external" ? (
+          <button
+            className="w-full text-left hover:underline"
+            onClick={onOpen}
+            type="button"
+          >
+            {content}
+          </button>
+        ) : (
+          content
+        )}
+        <details className="mt-1 text-xs text-muted-foreground">
+          <summary className="w-fit cursor-pointer">Details</summary>
+          <code className="mt-1 block break-all">{identity}</code>
+        </details>
+      </div>
+      {member.reference.type === "external" ? (
+        <Button asChild size="icon" variant="ghost">
+          <a href={member.reference.url} rel="noreferrer" target="_blank">
+            <ExternalLink className="h-4 w-4" />
+            <span className="sr-only">Open external reference</span>
+          </a>
+        </Button>
+      ) : null}
+      <CollectionRowActions
+        disabled={isRemoving}
+        label={member.label ?? member.reference.type}
+        onRemove={onRemove}
+      />
+    </div>
+  );
+}
+
+function SourceTypeGlyph({ type }: { type: CollectionReferenceType }) {
+  const Icon =
+    type === "channel"
+      ? Hash
+      : type === "repository"
+        ? GitBranch
+        : type === "task"
+          ? ListTodo
+          : type === "thread"
+            ? MessagesSquare
+            : type === "message"
+              ? MessageSquare
+              : type === "note"
+                ? StickyNote
+                : ExternalLink;
+  return (
+    <Icon
+      aria-label={`${type} source`}
+      className="h-4 w-4 shrink-0 text-muted-foreground"
+    />
+  );
+}
+
+export function CollectionRowActions({
+  derived = false,
+  disabled = false,
+  label,
+  onRemove,
+}: {
+  derived?: boolean;
+  disabled?: boolean;
+  label: string;
+  onRemove: () => Promise<void>;
+}) {
+  const removeLabel = derived
+    ? "Remove source from Collection"
+    : "Remove from Collection";
+  return (
+    <DropdownMenu>
+      <DropdownMenuTrigger asChild>
+        <Button
+          aria-label={`Actions for ${label}`}
+          className="opacity-60 transition-opacity hover:opacity-100 focus-visible:opacity-100 sm:opacity-0 sm:group-hover:opacity-100 sm:group-focus-within:opacity-100"
+          size="icon"
+          variant="ghost"
+        >
+          <Ellipsis className="h-4 w-4" />
+        </Button>
+      </DropdownMenuTrigger>
+      <DropdownMenuContent align="end">
+        <DropdownMenuItem
+          className="text-destructive focus:text-destructive"
+          disabled={disabled}
+          onSelect={() => void onRemove()}
+        >
+          {removeLabel}
+        </DropdownMenuItem>
+      </DropdownMenuContent>
+    </DropdownMenu>
+  );
+}
diff --git a/desktop/src/features/collections/ui/CollectionDetailScreen.tsx b/desktop/src/features/collections/ui/CollectionDetailScreen.tsx
index 5ae187af9d..c5af1f4229 100644
--- a/desktop/src/features/collections/ui/CollectionDetailScreen.tsx
+++ b/desktop/src/features/collections/ui/CollectionDetailScreen.tsx
@@ -3,20 +3,9 @@ import { openUrl } from "@tauri-apps/plugin-opener";
 import {
   ArrowLeft,
   Bot,
-  CalendarDays,
   Ellipsis,
-  ExternalLink,
-  FileText,
-  GitBranch,
-  GitPullRequest,
-  Hash,
-  Link2,
-  ListTodo,
-  MessageSquare,
-  MessagesSquare,
   Plus,
   Search,
-  StickyNote,
   UserRound,
 } from "lucide-react";
 import * as React from "react";
@@ -24,6 +13,7 @@ import { toast } from "sonner";
 
 import { useAppNavigation } from "@/app/navigation/useAppNavigation";
 import { useUsersBatchQuery } from "@/features/profile/hooks";
+import { truncatePubkey } from "@/shared/lib/pubkey";
 import { useOpenEntityLink } from "@/shared/ui/markdown/entityLinks";
 import { Button } from "@/shared/ui/button";
 import {
@@ -53,17 +43,15 @@ import {
   useCollectionQuery,
   useDerivedCollectionLinks,
 } from "../hooks";
-import {
-  type DerivedCollectionActivity,
-  projectCollectionActivity,
-} from "../derivedLinks";
-import type {
-  CollectionMember,
-  CollectionReference,
-  CollectionReferenceType,
-} from "../types";
+import { projectCollectionActivity } from "../derivedLinks";
+import type { CollectionReference, CollectionReferenceType } from "../types";
 import { useCollectionScope } from "../useCollectionScope";
 import { AddCollectionReferenceForm } from "./AddCollectionReferenceForm";
+import {
+  CollectionMemberRow,
+  CollectionRowActions,
+  DerivedCollectionActivityRow,
+} from "./CollectionDetailRows";
 import { CollectionGlyph } from "./CollectionGlyph";
 import { CollectionIconDialog } from "./CollectionIconDialog";
 
@@ -350,8 +338,8 @@ export function CollectionDetailScreen({
         >
           <TabsList aria-label="Collection sections">
             <TabsTrigger value="overview">Overview</TabsTrigger>
-            <TabsTrigger value="activity">Activity</TabsTrigger>
             <TabsTrigger value="sources">Sources</TabsTrigger>
+            <TabsTrigger value="activity">Activity</TabsTrigger>
           </TabsList>
         </Tabs>
 
@@ -598,7 +586,7 @@ export function CollectionDetailScreen({
                           ?.displayName ??
                         profiles[activity.authorPubkey.toLocaleLowerCase()]
                           ?.name ??
-                        activity.authorPubkey.slice(0, 8))
+                        truncatePubkey(activity.authorPubkey))
                       : undefined)
                   }
                   key={`${activity.activityType}:${activity.eventId ?? activity.url}:${activity.createdAt}`}
@@ -738,297 +726,3 @@ export function CollectionDetailScreen({
     </main>
   );
 }
-
-function DerivedCollectionActivityRow({
-  activity,
-  actorAvatarUrl,
-  actorLabel,
-  onOpenMessage,
-  onRemoveSource,
-}: {
-  activity: DerivedCollectionActivity;
-  actorAvatarUrl?: string;
-  actorLabel?: string;
-  onOpenMessage: () => void;
-  onRemoveSource: () => Promise<void>;
-}) {
-  const isMessage = activity.activityType === "channel-message";
-  const isDerived = !isMessage || activity.derivedFromSource === true;
-  const isDocumentActivity =
-    activity.activityType === "document-edit" ||
-    activity.activityType === "document-comment";
-  const isPullRequest = activity.activityType === "github-pr";
-  const isPullRequestActivity = activity.activityType === "github-pr-activity";
-  const identity = isMessage
-    ? activity.eventId
-    : isDocumentActivity || isPullRequestActivity
-      ? `${activity.url}:${activity.activityType}:${activity.createdAt}`
-      : activity.url;
-  const timestamp = activity.createdAt
-    ? new Intl.DateTimeFormat(undefined, {
-        dateStyle: "medium",
-        timeStyle: "short",
-      }).format(new Date(activity.createdAt * 1_000))
-    : null;
-  const content = (
-    <div className="min-w-0 flex-1">
-      <div className="flex items-center gap-2">
-        <ActivityTypeGlyph activity={activity} />
-        {isDerived ? (
-          <span
-            className="text-muted-foreground"
-            title={`Derived from ${activity.provenanceLabel ?? "an explicit Collection source"}`}
-          >
-            <Link2
-              aria-label={`Derived from ${activity.provenanceLabel ?? "an explicit Collection source"}`}
-              className="h-3.5 w-3.5"
-            />
-          </span>
-        ) : null}
-        <span className="truncate text-sm font-medium">{activity.label}</span>
-      </div>
-      {isDocumentActivity ? (
-        <div className="mt-1 text-sm">
-          {activity.actorLabel}{" "}
-          {activity.activityType === "document-edit"
-            ? "edited"
-            : "commented on"}{" "}
-          <span className="font-medium">{activity.label}</span>
-          {timestamp ? ` · ${timestamp}` : null}
-        </div>
-      ) : isPullRequestActivity ? (
-        <div className="mt-1 text-sm">
-          {activity.actorLabel ?? "Unknown GitHub actor"}{" "}
-          {activity.kind.replace(/^PR /u, "")}
-          {activity.stateLabel ? ` · ${activity.stateLabel}` : null}
-          {timestamp ? ` · ${timestamp}` : null}
-        </div>
-      ) : isPullRequest ? (
-        <div className="mt-1 text-sm">
-          {activity.stateLabel ? (
-            <span className="font-medium capitalize">
-              {activity.stateLabel}
-            </span>
-          ) : (
-            "Mentioned PR"
-          )}
-          {activity.actorLabel ? ` by ${activity.actorLabel}` : null}
-          {timestamp ? ` · ${timestamp}` : null}
-        </div>
-      ) : isMessage ? (
-        <div className="mt-1 text-sm">
-          {actorLabel ?? "Unknown Buzz user"}
-          {timestamp ? ` · ${timestamp}` : null}
-        </div>
-      ) : timestamp ? (
-        <div className="mt-1 text-xs text-muted-foreground">{timestamp}</div>
-      ) : null}
-      {activity.provenanceLabel ? (
-        <div className="mt-1 text-xs text-muted-foreground">
-          From {activity.provenanceLabel}
-        </div>
-      ) : null}
-      {activity.url ? (
-        <div className="mt-1 truncate text-xs text-muted-foreground">
-          {activity.url}
-        </div>
-      ) : null}
-    </div>
-  );
-  return (
-    <div
-      className="group flex items-center gap-3 p-4"
-      data-testid={`collection-derived-${encodeURIComponent(identity ?? "activity")}`}
-    >
-      {actorLabel ? (
-        <UserAvatar
-          avatarUrl={actorAvatarUrl ?? null}
-          displayName={actorLabel}
-          size="sm"
-        />
-      ) : null}
-      {isMessage ? (
-        <button
-          className="min-w-0 flex-1 text-left hover:underline"
-          onClick={onOpenMessage}
-          type="button"
-        >
-          {content}
-        </button>
-      ) : (
-        content
-      )}
-      {!isMessage ? (
-        <Button
-          aria-label={`Open derived link ${activity.label}`}
-          onClick={() => {
-            void openUrl(activity.url).catch(() =>
-              toast.error("Failed to open link"),
-            );
-          }}
-          size="icon"
-          variant="ghost"
-        >
-          <ExternalLink className="h-4 w-4" />
-        </Button>
-      ) : null}
-      <CollectionRowActions
-        derived={isDerived}
-        label={activity.label}
-        onRemove={onRemoveSource}
-      />
-    </div>
-  );
-}
-
-function ActivityTypeGlyph({
-  activity,
-}: {
-  activity: DerivedCollectionActivity;
-}) {
-  const Icon =
-    activity.activityType === "github-pr" ||
-    activity.activityType === "github-pr-activity"
-      ? GitPullRequest
-      : activity.activityType === "calendar-document"
-        ? CalendarDays
-        : activity.activityType === "channel-message"
-          ? activity.kind === "thread"
-            ? MessagesSquare
-            : MessageSquare
-          : FileText;
-  return (
-    <Icon
-      aria-label={activity.kind}
-      className="h-4 w-4 shrink-0 text-muted-foreground"
-    />
-  );
-}
-
-function CollectionMemberRow({
-  canOpen,
-  isRemoving,
-  member,
-  onOpen,
-  onRemove,
-}: {
-  canOpen: boolean;
-  isRemoving: boolean;
-  member: CollectionMember;
-  onOpen: () => void;
-  onRemove: () => Promise<void>;
-}) {
-  const identity = collectionReferenceIdentity(member.reference);
-  const label = member.label || identity;
-  const content = (
-    <div className="flex items-center gap-2">
-      <SourceTypeGlyph type={member.reference.type} />
-      <span className="truncate text-sm font-medium">{label}</span>
-      {member.reference.type === "external" ? (
-        <span className="rounded bg-muted px-2 py-0.5 text-xs text-muted-foreground">
-          {new URL(member.reference.url).hostname}
-        </span>
-      ) : null}
-    </div>
-  );
-
-  return (
-    <div
-      className="group flex items-center gap-3 p-4"
-      data-testid={`collection-member-${member.id}`}
-    >
-      <div className="min-w-0 flex-1">
-        {canOpen && member.reference.type !== "external" ? (
-          <button
-            className="w-full text-left hover:underline"
-            onClick={onOpen}
-            type="button"
-          >
-            {content}
-          </button>
-        ) : (
-          content
-        )}
-        <details className="mt-1 text-xs text-muted-foreground">
-          <summary className="w-fit cursor-pointer">Details</summary>
-          <code className="mt-1 block break-all">{identity}</code>
-        </details>
-      </div>
-      {member.reference.type === "external" ? (
-        <Button asChild size="icon" variant="ghost">
-          <a href={member.reference.url} rel="noreferrer" target="_blank">
-            <ExternalLink className="h-4 w-4" />
-            <span className="sr-only">Open external reference</span>
-          </a>
-        </Button>
-      ) : null}
-      <CollectionRowActions
-        disabled={isRemoving}
-        label={member.label ?? member.reference.type}
-        onRemove={onRemove}
-      />
-    </div>
-  );
-}
-
-function SourceTypeGlyph({ type }: { type: CollectionReferenceType }) {
-  const Icon =
-    type === "channel"
-      ? Hash
-      : type === "repository"
-        ? GitBranch
-        : type === "task"
-          ? ListTodo
-          : type === "thread"
-            ? MessagesSquare
-            : type === "message"
-              ? MessageSquare
-              : type === "note"
-                ? StickyNote
-                : ExternalLink;
-  return (
-    <Icon
-      aria-label={`${type} source`}
-      className="h-4 w-4 shrink-0 text-muted-foreground"
-    />
-  );
-}
-
-function CollectionRowActions({
-  derived = false,
-  disabled = false,
-  label,
-  onRemove,
-}: {
-  derived?: boolean;
-  disabled?: boolean;
-  label: string;
-  onRemove: () => Promise<void>;
-}) {
-  const removeLabel = derived
-    ? "Remove source from Collection"
-    : "Remove from Collection";
-  return (
-    <DropdownMenu>
-      <DropdownMenuTrigger asChild>
-        <Button
-          aria-label={`Actions for ${label}`}
-          className="opacity-60 transition-opacity hover:opacity-100 focus-visible:opacity-100 sm:opacity-0 sm:group-hover:opacity-100 sm:group-focus-within:opacity-100"
-          size="icon"
-          variant="ghost"
-        >
-          <Ellipsis className="h-4 w-4" />
-        </Button>
-      </DropdownMenuTrigger>
-      <DropdownMenuContent align="end">
-        <DropdownMenuItem
-          className="text-destructive focus:text-destructive"
-          disabled={disabled}
-          onSelect={() => void onRemove()}
-        >
-          {removeLabel}
-        </DropdownMenuItem>
-      </DropdownMenuContent>
-    </DropdownMenu>
-  );
-}