buzz/mobile

Buzz Mobile

Flutter mobile client for Buzz.

See VISION_MOBILE.md for intended behavior and architecture.

Builderlab builds

Three build-time settings, passed with Flutter's --dart-define (shell environment variables alone are not read), choose the build's single Builderlab. Set all three or none:

flutter run \
  --dart-define=BUZZ_DISTRIBUTION=public \
  --dart-define=BUZZ_BUILDERLAB_URL=https://app.builderlab.xyz \
  --dart-define=BUZZ_BUILDERLAB_RELAYS=communities.buzz.xyz

• BUZZ_DISTRIBUTION: public or internal. See the public build and internal build, and ADR 0001.
• BUZZ_BUILDERLAB_URL: the build's Builderlab HTTPS origin. On iOS, sign-in currently opens only Builderlab's own hosts (app.builderlab.xyz, or a <tenant>.builderlab.xyz organization) and their staging equivalents; the native browser bridge refuses any other origin.
• BUZZ_BUILDERLAB_RELAYS: comma-separated DNS domains whose relays use that Builderlab's session. Entries match the domain itself and its subdomains, case-insensitively. Use DNS names, not URLs or wildcards.

With none set, Builderlab features are disabled: no account login, community creation, backup/recovery UI, reconnect prompts, or background account restoration. QR/code pairing, community links and invites use Nostr-only entry. Saved account keys and sessions are retained for a later enabled build.

A public build signs in with Builderlab's web account setup, and requires it for communities under BUZZ_BUILDERLAB_RELAYS, which also places new communities under the first domain. QR pairing and other communities stay available.

An internal build offers one Sign in action that goes to the organization's single sign-on and then joins the community at its BUZZ_BUILDERLAB_RELAYS host. It has no QR pairing, community switching or community creation, refuses links to other relays, and hides communities on other relays that an earlier build saved, keeping their keys.

An internal build takes exactly one BUZZ_BUILDERLAB_RELAYS entry, its organization's relay host. It matches that exact host, not a domain, and the relay always receives its Builderlab session's relay assertions.

Agent creation links

buzz://agent/new?card=<id> opens the Agents page and an editable, pre-filled Create agent form for the active community. Opening a link never creates an agent. A Builderlab agent card's QR leads to its share page (app.builderlab.xyz/a/<id>), whose Add to Buzz button opens this link.

The app fetches <avatars CDN>/<id>/agent.json from the CDN for this build's Builderlab environment (HostedEnvironment.avatarsCdnOrigin), never from a host named by the link. The link carries only the id, so the QR stays small however long the instructions are.

{
  "id": "<id>",
  "name": "Scout",
  "avatarUrl": "https://<avatars CDN>/<id>/<revision>/avatar.png",
  "instructions": "Reply concisely.",
  "model": "<model catalog id>",
  "reasoningEffort": "high"
}

• id (the link's card id), name and avatarUrl (an https URL) are required. instructions, model and reasoningEffort are optional and left for the user when absent. A missing required field or a known field of the wrong type makes the card invalid, and no form opens. Other keys, including v and description, are ignored whatever their type. The card id is opaque to the app.
• Prefilled values are only a draft: Create applies its usual rules, so a name outside 1 to 64 letters, numbers, spaces, dots, hyphens or underscores, or instructions over 20,000 characters, must be edited before Create succeeds.
• The fetch shares the image loader's limits (lib/shared/utils/bounded_fetch.dart): it is aborted after 20 seconds without a byte or 5 minutes overall, and a card over 2 MB is rejected.
• model and reasoningEffort are pre-selected only if the live model catalog offers them (the effort only for that model).
• The link waits for sign-in and community load. It needs Builderlab login and a hosted community that supports remote agents. It reloads the signed-in account's agents first, and is dropped with a message if an unfinished agent setup exists (resume or discard that first) or the card can't be loaded.
• A link that arrives while Agents is open replaces it only when the list is all that's showing. With a form, profile or dialog open, the link is dropped with a message so unfinished work is kept.

The parser is lib/shared/deeplink/agent_creation_link.dart; the card reader is lib/features/agents/agent_creation_draft.dart.

Hosted relay authentication

--dart-define=BUZZ_HOSTED_RELAY_AUTH=true enables Builderlab relay assertions and reconnect sign-in for a public build's BUZZ_BUILDERLAB_RELAYS. It defaults off: configure backend assertion issuance before enabling mobile authentication, and enable relay enforcement last.

Setup

Use the Flutter SDK pinned by the repository. Activate Hermit from the repo root before resolving packages or running any Flutter command:

cd /path/to/buzz
. ./bin/activate-hermit
./bin/just mobile-install

mobile-build-android intentionally builds with --no-pub. If an IDE or an external Flutter SDK has touched mobile/.dart_tool, rerun mobile-install with the pinned SDK before building so flutter_test, sky_engine, and the engine all come from the same Flutter version.

iOS toolchain

Use Xcode 27.1 for iOS development and build validation on an Apple silicon Mac running macOS Tahoe 26.6 or later, as required by the Xcode 27 release notes. On Intel Macs or hosts that cannot meet those requirements, use a compatible Xcode 26 version, which remains supported. Activate the repository's pinned Flutter SDK with Hermit as described above.

When multiple Xcode versions are installed, select the intended version for the command with DEVELOPER_DIR, for example:

DEVELOPER_DIR=/Applications/Xcode-27.1.0.app/Contents/Developer xcodebuild -version

Adjust the path to your installation. Keep the compiler and SDK from the same Xcode installation. The pinned Flutter native-assets tooling can discover the globally selected SDK even when DEVELOPER_DIR selects another compiler, so use a build machine with a matching default Xcode when validating either Xcode 26 or Xcode 27.

The native cryptography dependency is pinned upstream C source in ios/BuzzPushKit/Sources/CSecp256k1; it requires no Swift build-plugin approval. GitHub's mobile CI currently uses the Xcode default of its macos-latest runner. The internal release toolchain is configured separately in buzz-releases.

Run

# From repo root (applies a worktree-isolated debug identity and starts/reuses Simulator):
just mobile-dev

# Direct (uses the app's configured community; apply worktree overrides first):
cd mobile && flutter run --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example

Worktree-aware debug identity

Debug builds produced from a git worktree get a unique app identifier keyed to the worktree directory name (xyz.block.buzz.dev.mobile.<slug> on iOS, xyz.block.buzz.mobile.<slug> on Android) plus a display-only branch label in the app name (Buzz (my-branch), or a short SHA when the worktree is detached). Because the identifier follows the directory rather than the branch, one worktree keeps exactly one installed app — and its login state — across branch switches, and builds from multiple worktrees install side by side, mirroring the desktop dev experience. Release and profile builds always keep the production identity and name.

just mobile-dev and just mobile-build-android apply this automatically by running scripts/mobile-worktree-overrides.sh, which writes two gitignored files:

• mobile/ios/Flutter/WorktreeOverrides.xcconfig (included by Debug builds only; a developer's AppOverrides.xcconfig is included after it, so app-specific overrides like a personal BUNDLE_IDENTIFIER for device signing always win)
• mobile/android/worktree.properties (read by the debug build type only)

Android developers can keep a stable local test identity that takes precedence over the generated worktree values by creating the gitignored mobile/android/AppOverrides.properties:

appName=Buzz Pairing
applicationIdSuffix=.device_pairing_e2e1

These values are consumed by the debug build type only. The standard just mobile-build-android command can still be used; regenerating worktree.properties does not overwrite AppOverrides.properties. Release and profile builds keep the production Buzz name and application ID.

For direct Xcode / Android Studio / flutter run development, run ./scripts/mobile-worktree-overrides.sh from the repo root once per branch switch to refresh the display label (the install identity never changes); the persisted files are then picked up by any subsequent build. In the main checkout the script is a no-op that removes stale override files, restoring the plain Buzz identity. To enable push in direct Xcode builds and Runner tests, supply a BUZZ_PUSH_GATEWAY_URL build setting in the gitignored mobile/ios/Flutter/AppOverrides.xcconfig; the build phase validates and passes it through as a Flutter Dart define. Since // begins an xcconfig comment, spell the origin as BUZZ_PUSH_GATEWAY_URL = https:/$()/push.example.

For an Android debug build that must remain installed alongside other Buzz worktree builds, set an explicit launcher name and package suffix when invoking the generator or a recipe that invokes it:

BUZZ_PUSH_GATEWAY_URL="https://push.example" \
BUZZ_ANDROID_DEBUG_APP_NAME="Buzz Huddles" \
BUZZ_ANDROID_DEBUG_ID_SUFFIX=".huddles_829c" \
./bin/just mobile-build-android

This example produces the debug-only package xyz.block.buzz.mobile.huddles_829c with the launcher label Buzz Huddles. The suffix must start with a dot followed by a lowercase letter and may contain only lowercase letters, digits, and underscores. Release and profile builds ignore these overrides and retain the production package and name.

To remove leftover worktree-suffixed installs from booted iOS simulators and connected Android emulators, run just mobile-clean (add --dry-run via ./scripts/mobile-worktree-clean.sh --dry-run to preview). Production installs are never touched.

iOS push capability

Every iOS artifact builds and embeds the Notification Service Extension and native push bridge. Runtime activation is fail-closed and scoped to the current relay. After authenticated connectivity and a fully valid NIP-11 buzz-push-v1 push descriptor, Buzz independently requests display permission and registers with APNs. Display denial or request failure does not gate the device token, gateway enrollment, or lease publication, so a later user opt-in can display pushes without rebuilding transport authority. An absent, malformed, or unreachable descriptor leaves push inactive without partial enrollment.

Mobile builds without a gateway origin succeed with push unavailable. To enable push, supply the gateway origin explicitly:

flutter build ios --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example
flutter build apk --dart-define=BUZZ_PUSH_GATEWAY_URL=https://push.example

The iOS and Android build gates validate any supplied define, rejecting empty or malformed values. Release/profile builds require an HTTPS origin without an explicit port. An absent define disables permission requests, APNs registration, gateway enrollment, and lease publication; Settings shows push as unavailable. No production gateway is selected implicitly. Enrollment grants and crash-recovery journals are scoped to this origin. Push has not shipped to existing users, so there is no legacy-state or cross-gateway migration. Changing gateways requires fresh enrollment; old installations expire under their original gateway's lease policy. Current-gateway response loss is still retried from the exact journaled request.

Relay rollout remains an explicit deployment opt-in. Only deployments with BUZZ_PUSH_ENABLED=true advertise the descriptor and process push. See docs/push-gateway-deployment.md for the canonical gateway profile contract, manual physical-device proof, measurements, and rollback procedure.

For local physical-device development, override the identity and sandbox environments in the gitignored mobile/ios/Flutter/AppOverrides.xcconfig:

BUNDLE_IDENTIFIER = com.example.buzz.mobile
BUZZ_DEVELOPMENT_TEAM = YOUR_TEAM_ID
BUZZ_IOS_PUSH_ENVIRONMENT = development
BUZZ_APP_ATTEST_ENVIRONMENT = development
BUZZ_PUSH_GATEWAY_URL = https:/$()/push.example

Use your personal bundle ID and team above. Provision both the parent and its .NotificationService extension. Configure an isolated gateway with the matching App Attest application ID, APNs topic and sandbox certificate. Development attestation requires the explicit personal-dev-app-attest gateway build feature and BUZZ_PUSH_APP_ATTEST_ENVIRONMENT=development; ordinary gateway builds accept production attestation only. See docs/push-gateway-deployment.md. Validate distributed builds separately using a signed release candidate and its matching gateway configuration.

Parent app identifiers require Apple's Communication Notifications capability and a regenerated app provisioning profile. The Notification Service Extension profile does not require that capability. Enable it on the personal development App ID for local rich-presentation validation. Enabling it on distribution App IDs is a release follow-up and is not performed by this repository change. Without a matching parent profile, source and unit validation still work, but the app cannot be signed for a physical device.

APNs and the gateway continue to carry only the constant opaque wake-up. The extension fetches the message from the scoped relay, verifies message, sender profile, and channel-metadata signatures, and uses a bounded App Group cache for names and app-rendered avatar thumbnails. It never fetches an avatar URL; missing, stale, or invalid enrichment falls back to the verified message with a short sender pubkey, community subtitle, and no image.

Checks

dart format --output=none --set-exit-if-changed .
flutter analyze
flutter test

Or from the repo root: just mobile-check and just mobile-test.

When writing tests, favor a few journey tests that drive real user flows over many small logic tests. See Testing Conventions.

Android release signing

Android release builds fail unless all upload-key inputs are supplied through the environment:

• BUZZ_ANDROID_UPLOAD_KEYSTORE_PATH: path to a CI-vended keystore file
• BUZZ_ANDROID_UPLOAD_KEYSTORE_PASSWORD
• BUZZ_ANDROID_UPLOAD_KEY_ALIAS
• BUZZ_ANDROID_UPLOAD_KEY_PASSWORD

The keystore path must be absolute, and the keystore must remain outside the repository. Development and debug builds do not require these variables.

Release pipelines that sign through the central APK Signer service instead of a local upload keystore must set BUZZ_ANDROID_RELEASE_SIGNING=external. That mode produces an unsigned release bundle and refuses to run if any BUZZ_ANDROID_UPLOAD_* value is also set.

Architecture

lib/
├── main.dart              # Entry point, Riverpod bootstrap
├── app.dart               # MaterialApp with theme
├── shared/
│   └── theme/             # Catppuccin light/dark, spacing tokens, extensions
└── features/
    └── home/              # Placeholder home surface

• State management: Riverpod + Hooks (HookConsumerWidget)
• Theme: Catppuccin Latte (light) / Macchiato (dark) — matches desktop
• Spacing: Grid tokens for consistent spacing
• Linting: flutter_lints + riverpod_lint via custom_lint
• Feature isolation: No cross-feature imports except shared/