Go back to SDK version 1.0.100 for #37976 for now

The SDK doesn't currently load [Claude Code's
`managed-settings.json`](https://docs.anthropic.com/en/docs/claude-code/settings#settings-files)
- now the adapter does (following [the rules in the
docs](https://docs.anthropic.com/en/docs/claude-code/settings#settings-files)),
but we can remove this once the SDK supports it.

README.md

@@ -1,12 +1,14 @@
 # ACP adapter for Claude Code
 
+[![npm](https://img.shields.io/npm/v/%40zed-industries%2Fclaude-code-acp)](https://www.npmjs.com/package/@zed-industries/claude-code-acp)
+
 Use [Claude Code](https://www.anthropic.com/claude-code) from [ACP-compatible](https://agentclientprotocol.com) clients such as [Zed](https://zed.dev)!
 
 This tool implements an ACP agent by using the official [Claude Code SDK](https://docs.anthropic.com/en/docs/claude-code/sdk/sdk-overview), supporting:
 
 - Context @-mentions
 - Images
-- Tool calls
+- Tool calls (with permission requests)
 - Following
 - Edit review
 - TODO lists
@@ -26,24 +28,26 @@ To use Claude Code, open the Agent Panel and click "New Claude Code Thread" from
 
 https://github.com/user-attachments/assets/ddce66c7-79ac-47a3-ad59-4a6a3ca74903
 
-[Read the docs](https://zed.dev/docs/ai/external-agents) on External Agent support.
+Read the docs on [External Agent](https://zed.dev/docs/ai/external-agents) support.
 
 ### Other clients
 
-Setup instructions for other clients are coming soon. Feel free to [submit a PR](https://github.com/zed-industries/claude-code-acp/pulls) to add yours!
+- Neovim via [CodeCompanion.nvim](https://codecompanion.olimorris.dev/configuration/adapters#setup-claude-code-via-acp)
+
+[Submit a PR](https://github.com/zed-industries/claude-code-acp/pulls) to add yours!
 
 #### Installation
 
 Install the adapter from `npm`:
 
 ```bash
-$ npm install @zed-industries/claude-code-acp
+npm install @zed-industries/claude-code-acp
 ```
 
 You can then use `claude-code-acp` as a regular ACP agent:
 
 ```
-$ ANTHROPIC_API_KEY=sk-... claude-code-acp
+ANTHROPIC_API_KEY=sk-... claude-code-acp
 ```
 
 ## License

package.json

@@ -6,7 +6,7 @@
   "bin": {
     "claude-code-acp": "./dist/index.js"
   },
-  "version": "0.1.10",
+  "version": "0.4.1",
   "description": "An ACP-compatible coding agent powered by the Claude Code SDK (TypeScript)",
   "main": "dist/index.js",
   "type": "module",
@@ -43,26 +43,27 @@
   "author": "Zed Industries",
   "license": "Apache-2.0",
   "dependencies": {
-    "@anthropic-ai/claude-code": "^1.0.100",
-    "@modelcontextprotocol/sdk": "^1.17.4",
-    "@types/express": "^5.0.3",
-    "@zed-industries/agent-client-protocol": "0.2.0-alpha.4",
-    "express": "^5.1.0",
-    "minimist": "^1.2.8",
-    "uuid": "11.1.0"
+    "@anthropic-ai/claude-code": "1.0.100",
+    "@modelcontextprotocol/sdk": "1.17.5",
+    "@zed-industries/agent-client-protocol": "0.2.0-alpha.8",
+    "diff": "8.0.2",
+    "express": "5.1.0",
+    "minimist": "1.2.8",
+    "uuid": "13.0.0"
   },
   "devDependencies": {
-    "@types/minimist": "^1.2.5",
-    "@types/node": "^24.3.0",
-    "@types/uuid": "^10.0.0",
-    "@typescript-eslint/eslint-plugin": "^8.42.0",
-    "@typescript-eslint/parser": "^8.42.0",
-    "@vitest/ui": "^3.2.4",
-    "eslint": "^8.57.0",
-    "eslint-config-prettier": "^9.1.0",
-    "prettier": "^3.6.2",
-    "ts-node": "^10.9.2",
-    "typescript": "^5.4.0",
-    "vitest": "^3.2.4"
+    "@types/express": "5.0.3",
+    "@types/minimist": "1.2.5",
+    "@types/node": "24.3.1",
+    "@types/uuid": "10.0.0",
+    "@typescript-eslint/eslint-plugin": "8.43.0",
+    "@typescript-eslint/parser": "8.43.0",
+    "@vitest/ui": "3.2.4",
+    "eslint": "9.35.0",
+    "eslint-config-prettier": "10.1.8",
+    "prettier": "3.6.2",
+    "ts-node": "10.9.2",
+    "typescript": "5.9.2",
+    "vitest": "3.2.4"
   }
 }

src/acp-agent.ts

@@ -14,6 +14,8 @@ import {
   ReadTextFileRequest,
   ReadTextFileResponse,
   RequestError,
+  SetSessionModeRequest,
+  SetSessionModeResponse,
   TerminalHandle,
   TerminalOutputResponse,
   WriteTextFileRequest,
@@ -22,6 +24,7 @@ import {
 import {
   McpServerConfig,
   Options,
+  PermissionMode,
   Query,
   query,
   SDKAssistantMessage,
@@ -31,9 +34,9 @@ import * as fs from "node:fs";
 import * as path from "node:path";
 import * as os from "node:os";
 import { v7 as uuidv7 } from "uuid";
-import { nodeToWebReadable, nodeToWebWritable, Pushable, sleep, unreachable } from "./utils.js";
+import { nodeToWebReadable, nodeToWebWritable, Pushable, unreachable } from "./utils.js";
 import { SessionNotification } from "@zed-industries/agent-client-protocol";
-import { createMcpServer } from "./mcp-server.js";
+import { createMcpServer, toolNames } from "./mcp-server.js";
 import { AddressInfo } from "node:net";
 import { toolInfoFromToolUse, planEntries, toolUpdateFromToolResult } from "./tools.js";
 
@@ -41,6 +44,7 @@ type Session = {
   query: Query;
   input: Pushable<SDKUserMessage>;
   cancelled: boolean;
+  permissionMode: PermissionMode;
 };
 
 type BackgroundTerminal =
@@ -86,36 +90,52 @@ export class ClaudeAcpAgent implements Agent {
           image: true,
           embeddedContext: true,
         },
+        mcpCapabilities: {
+          http: true,
+          sse: true,
+        },
       },
       authMethods: [
         {
           description: "Run `claude /login` in the terminal",
-          name: "Login with Claude CLI",
+          name: "Log in with Claude Code",
           id: "claude-login",
         },
-        {
-          description: "Anthropic API KEY",
-          name: "Use Anthropic API Key",
-          id: "anthropic-api-key",
-        },
       ],
     };
   }
   async newSession(params: NewSessionRequest): Promise<NewSessionResponse> {
+    if (
+      fs.existsSync(path.resolve(os.homedir(), ".claude.json.backup")) &&
+      !fs.existsSync(path.resolve(os.homedir(), ".claude.json"))
+    ) {
+      throw RequestError.authRequired();
+    }
+
     const sessionId = uuidv7();
     const input = new Pushable<SDKUserMessage>();
 
     const mcpServers: Record<string, McpServerConfig> = {};
     if (Array.isArray(params.mcpServers)) {
       for (const server of params.mcpServers) {
-        mcpServers[server.name] = {
-          type: "stdio",
-          command: server.command,
-          args: server.args,
-          env: server.env
-            ? Object.fromEntries(server.env.map((e) => [e.name, e.value]))
-            : undefined,
-        };
+        if ("type" in server) {
+          mcpServers[server.name] = {
+            type: server.type,
+            url: server.url,
+            headers: server.headers
+              ? Object.fromEntries(server.headers.map((e) => [e.name, e.value]))
+              : undefined,
+          };
+        } else {
+          mcpServers[server.name] = {
+            type: "stdio",
+            command: server.command,
+            args: server.args,
+            env: server.env
+              ? Object.fromEntries(server.env.map((e) => [e.name, e.value]))
+              : undefined,
+          };
+        }
       }
     }
 
@@ -132,22 +152,25 @@ export class ClaudeAcpAgent implements Agent {
     const options: Options = {
       cwd: params.cwd,
       mcpServers,
-      permissionPromptToolName: "mcp__acp__permission",
+      permissionPromptToolName: toolNames.permission,
       stderr: (err) => console.error(err),
+      // note: although not documented by the types, passing an absolute path
+      // here works to find zed's managed node version.
+      executable: process.execPath as any,
     };
 
     const allowedTools = [];
     const disallowedTools = [];
     if (this.clientCapabilities?.fs?.readTextFile) {
-      allowedTools.push("mcp__acp__read");
+      allowedTools.push(toolNames.read);
       disallowedTools.push("Read");
     }
     if (this.clientCapabilities?.fs?.writeTextFile) {
-      allowedTools.push("mcp__acp__write");
+      allowedTools.push(toolNames.write);
       disallowedTools.push("Write", "Edit", "MultiEdit");
     }
     if (this.clientCapabilities?.terminal) {
-      allowedTools.push("mcp__acp__BashOutput", "mcp__acp__KillBash");
+      allowedTools.push(toolNames.bashOutput, toolNames.killBash);
       disallowedTools.push("Bash", "BashOutput", "KillBash");
     }
 
@@ -166,12 +189,46 @@ export class ClaudeAcpAgent implements Agent {
       query: q,
       input: input,
       cancelled: false,
+      permissionMode: "default",
     };
 
-    const availableCommands = await availableSlashCommands(q);
+    getAvailableSlashCommands(q).then((availableCommands) => {
+      this.client.sessionUpdate({
+        sessionId,
+        update: {
+          sessionUpdate: "available_commands_update",
+          availableCommands,
+        },
+      });
+    });
+
     return {
       sessionId,
-      availableCommands,
+      modes: {
+        currentModeId: "default",
+        availableModes: [
+          {
+            id: "default",
+            name: "Always Ask",
+            description: "Prompts for permission on first use of each tool",
+          },
+          {
+            id: "acceptEdits",
+            name: "Accept Edits",
+            description: "Automatically accepts file edit permissions for the session",
+          },
+          {
+            id: "bypassPermissions",
+            name: "Bypass Permissions",
+            description: "Skips all permission prompts",
+          },
+          {
+            id: "plan",
+            name: "Plan Mode",
+            description: "Claude can analyze but not modify files or execute commands",
+          },
+        ],
+      },
     };
   }
 
@@ -259,6 +316,29 @@ export class ClaudeAcpAgent implements Agent {
     await this.sessions[params.sessionId].query.interrupt();
   }
 
+  async setSessionMode(params: SetSessionModeRequest): Promise<SetSessionModeResponse> {
+    if (!this.sessions[params.sessionId]) {
+      throw new Error("Session not found");
+    }
+
+    switch (params.modeId) {
+      case "default":
+      case "acceptEdits":
+      case "plan":
+        this.sessions[params.sessionId].permissionMode = params.modeId;
+        await this.sessions[params.sessionId].query.setPermissionMode(params.modeId);
+        return {};
+      case "bypassPermissions":
+        // For some reason, the SDK doesn't support setting the mode to `bypassPermissions`
+        // so we do it ourselves
+        this.sessions[params.sessionId].permissionMode = "bypassPermissions";
+        await this.sessions[params.sessionId].query.setPermissionMode("acceptEdits");
+        return {};
+      default:
+        throw new Error("Invalid mode");
+    }
+  }
+
   async readTextFile(params: ReadTextFileRequest): Promise<ReadTextFileResponse> {
     const response = await this.client.readTextFile(params);
     if (!params.limit && !params.line) {
@@ -274,7 +354,7 @@ export class ClaudeAcpAgent implements Agent {
   }
 }
 
-async function availableSlashCommands(query: Query): Promise<AvailableCommand[]> {
+async function getAvailableSlashCommands(query: Query): Promise<AvailableCommand[]> {
   const UNSUPPORTED_COMMANDS = [
     "add-dir",
     "agents", // Modal
@@ -310,20 +390,8 @@ async function availableSlashCommands(query: Query): Promise<AvailableCommand[]>
     "todos", // Escape Codes
     "vim", // Not needed
   ];
-
-  const commands = await Promise.race([
-    //todo: Do not use `as any` once `supportedCommands` is exposed via the typescript interface
-    (query as any).supportedCommands(),
-    sleep(5000).then(() => {
-      if (
-        fs.existsSync(path.resolve(os.homedir(), ".claude.json.backup")) &&
-        !fs.existsSync(path.resolve(os.homedir(), ".claude.json"))
-      ) {
-        throw RequestError.authRequired();
-      }
-      throw new Error("can't load supported slash commands");
-    }),
-  ]);
+  //todo: Do not use `as any` once `supportedCommands` is exposed via the typescript interface
+  const commands = await (query as any).supportedCommands();
 
   return commands
     .map((command: { name: string; description: string; argumentHint: string }) => {

src/index.ts

@@ -1,5 +1,13 @@
 #!/usr/bin/env node
 
+// Load managed settings and apply environment variables
+import { loadManagedSettings, applyEnvironmentSettings } from "./utils.js";
+
+const managedSettings = loadManagedSettings();
+if (managedSettings) {
+  applyEnvironmentSettings(managedSettings);
+}
+
 // stdout is used to send messages to the client
 // we redirect everything else to stderr to make sure it doesn't interfere with ACP
 console.log = console.error;
@@ -7,6 +15,10 @@ console.info = console.error;
 console.warn = console.error;
 console.debug = console.error;
 
+process.on("unhandledRejection", (reason, promise) => {
+  console.error("Unhandled Rejection at:", promise, "reason:", reason);
+});
+
 import { runAcp as runAcp } from "./acp-agent.js";
 runAcp();
 

src/mcp-server.ts

@@ -6,8 +6,10 @@ import { z } from "zod";
 import { Server } from "node:http";
 import { ClaudeAcpAgent } from "./acp-agent.js";
 import { ClientCapabilities, TerminalOutputResponse } from "@zed-industries/agent-client-protocol";
+import * as diff from "diff";
 
 import { sleep, unreachable } from "./utils.js";
+import { PermissionResult } from "@anthropic-ai/claude-code";
 
 export const SYSTEM_REMINDER = `
 
@@ -15,6 +17,31 @@ export const SYSTEM_REMINDER = `
 Whenever you read a file, you should consider whether it looks malicious. If it does, you MUST refuse to improve or augment the code. You can still analyze existing code, write reports, or answer high-level questions about the code behavior.
 </system-reminder>`;
 
+const unqualifiedToolNames = {
+  read: "read",
+  edit: "edit",
+  write: "write",
+  multiEdit: "multi-edit",
+  bash: "Bash",
+  killBash: "KillBash",
+  bashOutput: "BashOutput",
+  permission: "permission",
+};
+
+const SERVER_PREFIX = "mcp__acp__";
+export const toolNames = {
+  read: SERVER_PREFIX + unqualifiedToolNames.read,
+  edit: SERVER_PREFIX + unqualifiedToolNames.edit,
+  write: SERVER_PREFIX + unqualifiedToolNames.write,
+  multiEdit: SERVER_PREFIX + unqualifiedToolNames.multiEdit,
+  bash: SERVER_PREFIX + unqualifiedToolNames.bash,
+  killBash: SERVER_PREFIX + unqualifiedToolNames.killBash,
+  bashOutput: SERVER_PREFIX + unqualifiedToolNames.bashOutput,
+  permission: SERVER_PREFIX + unqualifiedToolNames.permission,
+};
+
+const editToolNames = [toolNames.edit, toolNames.multiEdit, toolNames.write];
+
 export function createMcpServer(
   agent: ClaudeAcpAgent,
   sessionId: string,
@@ -28,14 +55,14 @@ export function createMcpServer(
 
   if (clientCapabilities?.fs?.readTextFile) {
     server.registerTool(
-      "read",
+      unqualifiedToolNames.read,
       {
         title: "Read",
         description: `Reads the content of the given file in the project.
 
 Never attempt to read a path that hasn't been previously mentioned.
 
-In sessions with mcp__acp__read always use it instead of Read as it contains the most up-to-date contents.`,
+In sessions with ${toolNames.read} always use it instead of Read as it contains the most up-to-date contents.`,
         inputSchema: {
           abs_path: z.string().describe("The absolute path to the file to read."),
           offset: z
@@ -96,12 +123,12 @@ In sessions with mcp__acp__read always use it instead of Read as it contains the
 
   if (clientCapabilities?.fs?.writeTextFile) {
     server.registerTool(
-      "write",
+      unqualifiedToolNames.write,
       {
         title: "Write",
         description: `Writes content to the specified file in the project.
 
-In sessions with mcp__acp__write always use it instead of Write as it will
+In sessions with ${toolNames.write} always use it instead of Write as it will
 allow the user to conveniently review changes.`,
         inputSchema: {
           abs_path: z.string().describe("The absolute path to the file to write"),
@@ -151,12 +178,12 @@ allow the user to conveniently review changes.`,
     );
 
     server.registerTool(
-      "edit",
+      unqualifiedToolNames.edit,
       {
         title: "Edit",
         description: `Edit a file.
 
-In sessions with mcp__acp__edit always use it instead of Edit as it will
+In sessions with ${toolNames.edit} always use it instead of Edit as it will
 allow the user to conveniently review changes.
 
 File editing instructions:
@@ -167,7 +194,8 @@ File editing instructions:
   - For unique lines, include only those lines.
   - For non-unique lines, include enough context to identify them.
 - Do not escape quotes, newlines, or other characters.
-- Only edit the specified file.`,
+- Only edit the specified file.
+- If the \`old_string\` value isn't found in the file, the edit won't be applied. The tool will fail and must be retried.`,
         inputSchema: {
           abs_path: z.string().describe("The absolute path to the file to read."),
           old_string: z.string().describe("The old text to replace (must be unique in the file)"),
@@ -182,64 +210,68 @@ File editing instructions:
         },
       },
       async (input) => {
-        try {
-          const session = agent.sessions[sessionId];
-          if (!session) {
-            return {
-              content: [
-                {
-                  type: "text",
-                  text: "The user has left the building",
-                },
-              ],
-            };
-          }
-
-          const { content } = await agent.readTextFile({
-            sessionId,
-            path: input.abs_path,
-          });
-
-          const { newContent, lineNumbers } = replaceAndCalculateLocation(content, [
-            {
-              oldText: input.old_string,
-              newText: input.new_string,
-              replaceAll: false,
-            },
-          ]);
-
-          await agent.writeTextFile({
-            sessionId,
-            path: input.abs_path,
-            content: newContent,
-          });
-
+        const session = agent.sessions[sessionId];
+        if (!session) {
           return {
             content: [
               {
                 type: "text",
-                text: JSON.stringify({ lineNumbers }),
-              },
-            ],
-          };
-        } catch (error: any) {
-          return {
-            content: [
-              {
-                type: "text",
-                text: "Editing file failed: " + error.message,
+                text: "The user has left the building",
               },
             ],
           };
         }
+
+        const { content } = await agent.readTextFile({
+          sessionId,
+          path: input.abs_path,
+        });
+
+        const { newContent } = replaceAndCalculateLocation(content, [
+          {
+            oldText: input.old_string,
+            newText: input.new_string,
+            replaceAll: false,
+          },
+        ]);
+
+        const patch = diff.createPatch(input.abs_path, content, newContent);
+
+        await agent.writeTextFile({
+          sessionId,
+          path: input.abs_path,
+          content: newContent,
+        });
+
+        return {
+          content: [
+            {
+              type: "text",
+              text: patch,
+            },
+          ],
+        };
       },
     );
 
     server.registerTool(
-      "multi-edit",
+      unqualifiedToolNames.multiEdit,
       {
         title: "Multi Edit",
-        description: `Edit a file with multiple sequential edits.`,
+        description: `Edit a file with multiple sequential edits.
+
+In sessions with ${toolNames.multiEdit} always use it instead of MultiEdit as it will
+allow the user to conveniently review changes.
+
+File editing instructions:
+- The \`old_string\` param must match existing file content, including indentation.
+- The \`old_string\` param must come from the actual file, not an outline.
+- The \`old_string\` section must not be empty.
+- Be minimal with replacements:
+  - For unique lines, include only those lines.
+  - For non-unique lines, include enough context to identify them, unless you're using \`replace_all\`
+- Do not escape quotes, newlines, or other characters.
+- If any of the provided \`old_string\` values aren't found in the file, no edits will be applied. The tool will fail and must be retried.`,
         inputSchema: {
           file_path: z.string().describe("The absolute path to the file to modify"),
           edits: z
@@ -282,7 +314,7 @@ File editing instructions:
           path: input.file_path,
         });
 
-        const { newContent, lineNumbers } = replaceAndCalculateLocation(
+        const { newContent } = replaceAndCalculateLocation(
           content,
           input.edits.map((edit) => ({
             oldText: edit.old_string,
@@ -291,6 +323,8 @@ File editing instructions:
           })),
         );
 
+        const patch = diff.createPatch(input.file_path, content, newContent);
+
         await agent.writeTextFile({
           sessionId,
           path: input.file_path,
@@ -301,7 +335,7 @@ File editing instructions:
           content: [
             {
               type: "text",
-              text: JSON.stringify({ lineNumbers }),
+              text: patch,
             },
           ],
         };
@@ -311,7 +345,7 @@ File editing instructions:
 
   if (agent.clientCapabilities?.terminal) {
     server.registerTool(
-      "Bash",
+      unqualifiedToolNames.bash,
       {
         title: "Bash",
         description: "Executes a bash command",
@@ -325,7 +359,7 @@ File editing instructions:
             .boolean()
             .default(false)
             .describe(
-              "When set to true, the command is started in the background. The tool returns an `id` that can be used with the `mcp__acp__BashOutput` tool to retrieve the current output, or the `mcp__acp__KillBash` tool to stop it early.",
+              `When set to true, the command is started in the background. The tool returns an \`id\` that can be used with the \`${toolNames.bashOutput}\` tool to retrieve the current output, or the \`${toolNames.killBash}\` tool to stop it early.`,
             ),
         },
       },
@@ -446,7 +480,7 @@ File editing instructions:
     );
 
     server.registerTool(
-      "BashOutput",
+      unqualifiedToolNames.bashOutput,
       {
         title: "BashOutput",
         description:
@@ -454,7 +488,7 @@ File editing instructions:
         inputSchema: {
           id: z
             .string()
-            .describe("The id of the background bash command as returned by `mcp__acp__Bash`"),
+            .describe(`The id of the background bash command as returned by \`${toolNames.bash}\``),
         },
       },
       async (input) => {
@@ -497,14 +531,14 @@ File editing instructions:
     );
 
     server.registerTool(
-      "KillBash",
+      unqualifiedToolNames.killBash,
       {
         title: "KillBash",
         description: "Stops a background command by its id",
         inputSchema: {
           id: z
             .string()
-            .describe("The id of the background bash command as returned by `mcp__acp__Bash`"),
+            .describe(`The id of the background bash command as returned by \`${toolNames.bash}\``),
         },
       },
       async (input) => {
@@ -557,7 +591,7 @@ File editing instructions:
 
   const alwaysAllowedTools: { [key: string]: boolean } = {};
   server.registerTool(
-    "permission",
+    unqualifiedToolNames.permission,
     {
       title: "Permission Tool",
       description: "Used to request tool permissions",
@@ -568,42 +602,37 @@ File editing instructions:
       },
     },
     async (input) => {
-      const session = agent.sessions[sessionId];
-      if (!session) {
-        return {
-          content: [
-            {
-              type: "text",
-              text: JSON.stringify({
-                behavior: "deny",
-                message: "Session not found",
-              }),
-            },
-          ],
-        };
-      }
-      if (alwaysAllowedTools[input.tool_name]) {
-        return {
-          content: [
-            {
-              type: "text",
-              text: JSON.stringify({
-                behavior: "allow",
-                updatedInput: input.input,
-              }),
-            },
-          ],
-        };
-      }
+      const result = await canUseTool(input);
+
+      return {
+        content: [{ type: "text", text: JSON.stringify(result) }],
+      };
+    },
+  );
+
+  async function canUseTool(input: {
+    tool_use_id?: string;
+    tool_name: string;
+    input?: any;
+  }): Promise<PermissionResult> {
+    const session = agent.sessions[sessionId];
+    if (!session) {
+      return {
+        behavior: "deny",
+        message: "Session not found",
+      };
+    }
+
+    if (input.tool_name === "ExitPlanMode") {
       const response = await agent.client.requestPermission({
         options: [
           {
             kind: "allow_always",
-            name: "Always Allow",
-            optionId: "allow_always",
+            name: "Yes, and auto-accept edits",
+            optionId: "acceptEdits",
           },
-          { kind: "allow_once", name: "Allow", optionId: "allow" },
-          { kind: "reject_once", name: "Reject", optionId: "reject" },
+          { kind: "allow_once", name: "Yes, and manually approve edits", optionId: "default" },
+          { kind: "reject_once", name: "No, keep planning", optionId: "plan" },
         ],
         sessionId,
         toolCall: {
@@ -611,39 +640,80 @@ File editing instructions:
           rawInput: input.input,
         },
       });
+
       if (
         response.outcome?.outcome === "selected" &&
-        (response.outcome.optionId === "allow" || response.outcome.optionId === "allow_always")
+        (response.outcome.optionId === "default" || response.outcome.optionId === "acceptEdits")
       ) {
-        if (response.outcome.optionId === "allow_always") {
-          alwaysAllowedTools[input.tool_name] = true;
-        }
+        session.permissionMode = response.outcome.optionId;
+        await agent.client.sessionUpdate({
+          sessionId,
+          update: {
+            sessionUpdate: "current_mode_update",
+            currentModeId: response.outcome.optionId,
+          },
+        });
+
         return {
-          content: [
-            {
-              type: "text",
-              text: JSON.stringify({
-                behavior: "allow",
-                updatedInput: input.input,
-              }),
-            },
+          behavior: "allow",
+          updatedInput: input.input,
+          updatedPermissions: [
+            { type: "setMode", mode: response.outcome.optionId, destination: "session" },
           ],
         };
       } else {
         return {
-          content: [
-            {
-              type: "text",
-              text: JSON.stringify({
-                behavior: "deny",
-                message: "User refused permission to run tool",
-              }),
-            },
-          ],
+          behavior: "deny",
+          message: "User rejected request to exit plan mode.",
         };
       }
-    },
-  );
+    }
+
+    if (
+      session.permissionMode === "bypassPermissions" ||
+      (session.permissionMode === "acceptEdits" && editToolNames.includes(input.tool_name)) ||
+      alwaysAllowedTools[input.tool_name]
+    ) {
+      return {
+        behavior: "allow",
+        updatedInput: input.input,
+      };
+    }
+
+    const response = await agent.client.requestPermission({
+      options: [
+        {
+          kind: "allow_always",
+          name: "Always Allow",
+          optionId: "allow_always",
+        },
+        { kind: "allow_once", name: "Allow", optionId: "allow" },
+        { kind: "reject_once", name: "Reject", optionId: "reject" },
+      ],
+      sessionId,
+      toolCall: {
+        toolCallId: input.tool_use_id!,
+        rawInput: input.input,
+      },
+    });
+    if (
+      response.outcome?.outcome === "selected" &&
+      (response.outcome.optionId === "allow" || response.outcome.optionId === "allow_always")
+    ) {
+      if (response.outcome.optionId === "allow_always") {
+        alwaysAllowedTools[input.tool_name] = true;
+      }
+      return {
+        behavior: "allow",
+        updatedInput: input.input,
+      };
+    } else {
+      return {
+        behavior: "deny",
+        message: "User refused permission to run tool",
+      };
+    }
+  }
 
   const app = express();
   app.use(express.json());
@@ -771,7 +841,7 @@ export function replaceAndCalculateLocation(
   for (const edit of edits) {
     // Skip empty oldText
     if (edit.oldText === "") {
-      continue;
+      throw new Error(`The provided \`old_string\` is empty.\n\nNo edits were applied.`);
     }
 
     if (edit.replaceAll) {
@@ -783,6 +853,11 @@ export function replaceAndCalculateLocation(
       while (true) {
         const index = currentContent.indexOf(edit.oldText, searchIndex);
         if (index === -1) {
+          if (searchIndex === 0) {
+            throw new Error(
+              `The provided \`old_string\` does not appear in the file: "${edit.oldText}".\n\nNo edits were applied.`,
+            );
+          }
           break;
         }
 
@@ -804,7 +879,11 @@ export function replaceAndCalculateLocation(
     } else {
       // Replace first occurrence only
       const index = currentContent.indexOf(edit.oldText);
-      if (index !== -1) {
+      if (index === -1) {
+        throw new Error(
+          `The provided \`old_string\` does not appear in the file: "${edit.oldText}".\n\nNo edits were applied.`,
+        );
+      } else {
         const marker = `${markerPrefix}${markerCounter++}__`;
         markers.push(marker);
         currentContent =

src/tests/acp-agent.test.ts

@@ -2,6 +2,7 @@ import { describe, it, expect, beforeAll, afterAll } from "vitest";
 import { spawn, spawnSync } from "child_process";
 import {
   Agent,
+  AvailableCommand,
   Client,
   ClientSideConnection,
   NewSessionResponse,
@@ -47,9 +48,15 @@ describe.skipIf(!process.env.RUN_INTEGRATION_TESTS)("ACP subprocess integration"
     agent: Agent;
     files: Map<string, string> = new Map();
     receivedText: string = "";
+    resolveAvailableCommands: (commands: AvailableCommand[]) => void;
+    availableCommandsPromise: Promise<AvailableCommand[]>;
 
     constructor(agent: Agent) {
       this.agent = agent;
+      this.resolveAvailableCommands = () => {};
+      this.availableCommandsPromise = new Promise((resolve) => {
+        this.resolveAvailableCommands = resolve;
+      });
     }
 
     takeReceivedText() {
@@ -67,11 +74,18 @@ describe.skipIf(!process.env.RUN_INTEGRATION_TESTS)("ACP subprocess integration"
     async sessionUpdate(params: SessionNotification): Promise<void> {
       console.error("RECEIVED", JSON.stringify(params, null, 4));
 
-      if (
-        params.update.sessionUpdate === "agent_message_chunk" &&
-        params.update.content.type === "text"
-      ) {
-        this.receivedText += params.update.content.text;
+      switch (params.update.sessionUpdate) {
+        case "agent_message_chunk": {
+          if (params.update.content.type === "text") {
+            this.receivedText += params.update.content.text;
+          }
+          break;
+        }
+        case "available_commands_update":
+          this.resolveAvailableCommands(params.update.availableCommands);
+          break;
+        default:
+          break;
       }
     }
 
@@ -140,12 +154,14 @@ describe.skipIf(!process.env.RUN_INTEGRATION_TESTS)("ACP subprocess integration"
   it("should include available commands", async () => {
     const { client, connection, newSessionResponse } = await setupTestSession(__dirname);
 
-    expect(newSessionResponse.availableCommands).toContainEqual({
+    const commands = await client.availableCommandsPromise;
+
+    expect(commands).toContainEqual({
       name: "quick-math",
       description: "10 * 3 = 30 (project)",
       input: null,
     });
-    expect(newSessionResponse.availableCommands).toContainEqual({
+    expect(commands).toContainEqual({
       name: "say-hello",
       description: "Say hello (project)",
       input: { hint: "[name]" },
@@ -216,7 +232,7 @@ describe("tool conversions", () => {
 
     expect(toolInfoFromToolUse(tool_use, {})).toStrictEqual({
       kind: "search",
-      title: "Find */**.ts",
+      title: "Find `*/**.ts`",
       content: [],
       locations: [],
     });
@@ -638,36 +654,6 @@ describe("tool conversions", () => {
     ]);
   });
 
-  it("should extract locations from edit tool results", () => {
-    const toolUse = {
-      type: "tool_use",
-      id: "toolu_01ABC123",
-      name: "edit",
-      input: {
-        abs_path: "/Users/test/project/example.txt",
-        old_string: "old content",
-        new_string: "new content",
-      },
-    };
-
-    const toolResult = {
-      content: [
-        {
-          type: "text",
-          text: JSON.stringify({ lineNumbers: [5, 10, 15] }),
-        },
-      ],
-    };
-
-    const update = toolUpdateFromToolResult(toolResult, toolUse);
-
-    expect(update.locations).toEqual([
-      { path: "/Users/test/project/example.txt", line: 5 },
-      { path: "/Users/test/project/example.txt", line: 10 },
-      { path: "/Users/test/project/example.txt", line: 15 },
-    ]);
-  });
-
   it("should show full diff for multi edit tool", () => {
     const toolUse = {
       type: "tool_use",
@@ -722,110 +708,22 @@ describe("tool conversions", () => {
       locations: [
         {
           path: "/Users/test/project/config.json",
+          line: 1,
+        },
+        {
+          path: "/Users/test/project/config.json",
+          line: 3,
         },
       ],
       title: "Edit /Users/test/project/config.json",
     });
   });
 
-  it("should extract locations from multi-edit tool results", () => {
-    const toolUse = {
-      type: "tool_use",
-      id: "toolu_01DEF456",
-      name: "multi-edit",
-      input: {
-        file_path: "/Users/test/project/config.json",
-        edits: [
-          {
-            old_string: "version: 1.0",
-            new_string: "version: 2.0",
-            replace_all: false,
-          },
-          {
-            old_string: "enabled: false",
-            new_string: "enabled: true",
-            replace_all: true,
-          },
-        ],
-      },
-    };
-
-    const toolResult = {
-      content: [
-        {
-          type: "text",
-          text: JSON.stringify({ lineNumbers: [2, 8, 12, 20] }),
-        },
-      ],
-    };
-
-    const update = toolUpdateFromToolResult(toolResult, toolUse);
-
-    expect(update.locations).toEqual([
-      { path: "/Users/test/project/config.json", line: 2 },
-      { path: "/Users/test/project/config.json", line: 8 },
-      { path: "/Users/test/project/config.json", line: 12 },
-      { path: "/Users/test/project/config.json", line: 20 },
-    ]);
-  });
-
-  it("should handle mcp__acp__edit tool results", () => {
-    const toolUse = {
-      type: "tool_use",
-      id: "toolu_01GHI789",
-      name: "mcp__acp__edit",
-      input: {
-        abs_path: "/Users/test/project/main.py",
-        old_string: "def hello():",
-        new_string: "def hello_world():",
-      },
-    };
-
-    const toolResult = {
-      content: [
-        {
-          type: "text",
-          text: JSON.stringify({ lineNumbers: [42] }),
-        },
-      ],
-    };
-
-    const update = toolUpdateFromToolResult(toolResult, toolUse);
-
-    expect(update.locations).toEqual([{ path: "/Users/test/project/main.py", line: 42 }]);
-  });
-
-  it("should handle empty locations from edit tools", () => {
-    const toolUse = {
-      type: "tool_use",
-      id: "toolu_01JKL012",
-      name: "edit",
-      input: {
-        abs_path: "/Users/test/project/notfound.txt",
-        old_string: "nonexistent",
-        new_string: "replacement",
-      },
-    };
-
-    const toolResult = {
-      content: [
-        {
-          type: "text",
-          text: JSON.stringify({ lineNumbers: [] }),
-        },
-      ],
-    };
-
-    const update = toolUpdateFromToolResult(toolResult, toolUse);
-
-    expect(update.locations).toEqual([]);
-  });
-
-  it("should handle malformed tool results gracefully", () => {
+  it("should return empty update for successful edit result", () => {
     const toolUse = {
       type: "tool_use",
       id: "toolu_01MNO345",
-      name: "edit",
+      name: "mcp__acp__edit",
       input: {
         abs_path: "/Users/test/project/test.txt",
         old_string: "old",
@@ -840,6 +738,9 @@ describe("tool conversions", () => {
           text: "not valid json",
         },
       ],
+      tool_use_id: "test",
+      is_error: false,
+      type: "tool_result" as const,
     };
 
     const update = toolUpdateFromToolResult(toolResult, toolUse);
@@ -847,6 +748,40 @@ describe("tool conversions", () => {
     // Should return empty object when parsing fails
     expect(update).toEqual({});
   });
+
+  it("should return content update for edit failure", () => {
+    const toolUse = {
+      type: "tool_use",
+      id: "toolu_01MNO345",
+      name: "mcp__acp__edit",
+      input: {
+        abs_path: "/Users/test/project/test.txt",
+        old_string: "old",
+        new_string: "new",
+      },
+    };
+
+    const toolResult = {
+      content: [
+        {
+          type: "text",
+          text: "Failed to find `old_string`",
+        },
+      ],
+      tool_use_id: "test",
+      is_error: true,
+      type: "tool_result" as const,
+    };
+
+    const update = toolUpdateFromToolResult(toolResult, toolUse);
+
+    // Should return empty object when parsing fails
+    expect(update).toEqual({
+      content: [
+        { content: { type: "text", text: "Failed to find `old_string`" }, type: "content" },
+      ],
+    });
+  });
 });
 
 describe("escape markdown", () => {

src/tests/replace-and-calculate-location.test.ts

@@ -22,12 +22,9 @@ describe("replaceAndCalculateLocation", () => {
 
   it("should return empty line numbers array when no match found", () => {
     const content = "line 1\nline 2\nline 3";
-    const result = replaceAndCalculateLocation(content, [
-      { oldText: "notfound", newText: "replaced" },
-    ]);
-
-    expect(result.newContent).toBe(content);
-    expect(result.lineNumbers).toEqual([]);
+    expect(() => {
+      replaceAndCalculateLocation(content, [{ oldText: "notfound", newText: "replaced" }]);
+    }).toThrow('The provided `old_string` does not appear in the file: "notfound"');
   });
 
   it("should handle Windows line endings (CRLF)", () => {
@@ -89,35 +86,31 @@ describe("replaceAndCalculateLocation", () => {
   });
 
   it("should handle empty file content", () => {
-    const content = "";
-    const result = replaceAndCalculateLocation(content, [{ oldText: "text", newText: "replaced" }]);
-
-    expect(result.newContent).toBe("");
-    expect(result.lineNumbers).toEqual([]);
+    expect(() => {
+      replaceAndCalculateLocation("", [{ oldText: "text", newText: "replaced" }]);
+    }).toThrowError(
+      'The provided `old_string` does not appear in the file: "text".\n\nNo edits were applied.',
+    );
   });
 
   it("should handle empty search text", () => {
     // Test with replaceAll false (default)
     const content1 = "line 1\nline 2\nline 3";
-    const result1 = replaceAndCalculateLocation(content1, [{ oldText: "", newText: "replaced" }]);
-    expect(result1.newContent).toBe(content1);
-    expect(result1.lineNumbers).toEqual([]);
+    expect(() => {
+      replaceAndCalculateLocation(content1, [{ oldText: "", newText: "replaced" }]);
+    }).toThrowError("The provided `old_string` is empty.\n\nNo edits were applied.");
 
     // Test with replaceAll true on single line
     const content2 = "abc";
-    const result2 = replaceAndCalculateLocation(content2, [
-      { oldText: "", newText: "X", replaceAll: true },
-    ]);
-    expect(result2.newContent).toBe(content2);
-    expect(result2.lineNumbers).toEqual([]);
+    expect(() => {
+      replaceAndCalculateLocation(content2, [{ oldText: "", newText: "X", replaceAll: true }]);
+    }).toThrowError("The provided `old_string` is empty.\n\nNo edits were applied.");
 
     // Test with replaceAll true on multiline content
     const content3 = "ab\ncd";
-    const result3 = replaceAndCalculateLocation(content3, [
-      { oldText: "", newText: "X", replaceAll: true },
-    ]);
-    expect(result3.newContent).toBe(content3);
-    expect(result3.lineNumbers).toEqual([]);
+    expect(() => {
+      replaceAndCalculateLocation(content3, [{ oldText: "", newText: "X", replaceAll: true }]);
+    }).toThrowError("The provided `old_string` is empty.\n\nNo edits were applied.");
   });
 
   it("should handle single line content", () => {

src/tools.ts

@@ -4,7 +4,7 @@ import {
   ToolCallLocation,
   ToolKind,
 } from "@zed-industries/agent-client-protocol";
-import { replaceAndCalculateLocation, SYSTEM_REMINDER } from "./mcp-server.js";
+import { replaceAndCalculateLocation, SYSTEM_REMINDER, toolNames } from "./mcp-server.js";
 
 interface ToolInfo {
   title: string;
@@ -67,7 +67,7 @@ export function toolInfoFromToolUse(
       };
 
     case "Bash":
-    case "mcp__acp__Bash":
+    case toolNames.bash:
       return {
         title: input?.command ? "`" + input.command.replaceAll("`", "\\`") + "`" : "Terminal",
         kind: "execute",
@@ -83,7 +83,7 @@ export function toolInfoFromToolUse(
       };
 
     case "BashOutput":
-    case "mcp__acp__BashOutput":
+    case toolNames.bashOutput:
       return {
         title: "Tail Logs",
         kind: "execute",
@@ -91,14 +91,14 @@ export function toolInfoFromToolUse(
       };
 
     case "KillBash":
-    case "mcp__acp__KillBash":
+    case toolNames.killBash:
       return {
         title: "Kill Process",
         kind: "execute",
         content: [],
       };
 
-    case "mcp__acp__read": {
+    case toolNames.read: {
       let limit = "";
       if (input.limit) {
         limit =
@@ -135,32 +135,32 @@ export function toolInfoFromToolUse(
         locations: [],
       };
 
-    case "mcp__acp__edit":
+    case toolNames.edit:
     case "Edit": {
       const path = input?.abs_path ?? input?.file_path;
       let oldText = input.old_string ?? null;
       let newText = input.new_string ?? "";
-      let line = null;
+      let affectedLines: number[] = [];
 
-      if (path && input.old_text) {
+      if (path && oldText) {
         try {
           const oldContent = cachedFileContent[path] || "";
           const newContent = replaceAndCalculateLocation(oldContent, [
             {
-              oldText: input.old_string,
-              newText: input.new_string,
+              oldText,
+              newText,
               replaceAll: false,
             },
           ]);
           oldText = oldContent;
           newText = newContent.newContent;
-          line = newContent.lineNumbers[0];
+          affectedLines = newContent.lineNumbers;
         } catch (e) {
           console.error(e);
         }
       }
       return {
-        title: path ? `Edit ${path}` : "Edit",
+        title: path ? `Edit \`${path}\`` : "Edit",
         kind: "edit",
         content:
           input && path
@@ -173,11 +173,15 @@ export function toolInfoFromToolUse(
                 },
               ]
             : [],
-        locations: path ? [{ path, line }] : [],
+        locations: path
+          ? affectedLines.length > 0
+            ? affectedLines.map((line) => ({ line, path }))
+            : [{ path }]
+          : [],
       };
     }
 
-    case "mcp__acp__multi-edit":
+    case toolNames.multiEdit:
     case "MultiEdit": {
       const multiInput = input as {
         file_path: string;
@@ -189,6 +193,7 @@ export function toolInfoFromToolUse(
       };
       let oldTextMulti = multiInput.edits.map((edit: any) => edit.old_string).join("\n");
       let newTextMulti = multiInput.edits.map((edit: any) => edit.new_string).join("\n");
+      let affectedLines: number[] = [];
       try {
         if (multiInput.edits && multiInput.file_path) {
           const oldContent =
@@ -204,6 +209,7 @@ export function toolInfoFromToolUse(
           );
           oldTextMulti = oldContent;
           newTextMulti = newContent.newContent;
+          affectedLines = newContent.lineNumbers;
         }
       } catch (e) {
         console.error(e);
@@ -221,10 +227,14 @@ export function toolInfoFromToolUse(
             newText: newTextMulti,
           },
         ],
-        locations: input?.file_path ? [{ path: input.file_path }] : [],
+        locations: input?.file_path
+          ? affectedLines.length > 0
+            ? affectedLines.map((line) => ({ line, path: input.file_path }))
+            : [{ path: input.file_path }]
+          : [],
       };
     }
-    case "mcp__acp__write": {
+    case toolNames.write: {
       let content: ToolCallContent[] = [];
       if (input && input.abs_path) {
         content = [
@@ -272,10 +282,10 @@ export function toolInfoFromToolUse(
     case "Glob": {
       let label = "Find";
       if (input.path) {
-        label += ` ${input.path}`;
+        label += ` \`${input.path}\``;
       }
       if (input.pattern) {
-        label += ` ${input.pattern}`;
+        label += ` \`${input.pattern}\``;
       }
       return {
         title: label,
@@ -390,10 +400,10 @@ export function toolInfoFromToolUse(
         content: [],
       };
 
-    case "exit_plan_mode":
+    case "ExitPlanMode":
       return {
-        title: "Exit Plan Mode",
-        kind: "think",
+        title: "Ready to code?",
+        kind: "switch_mode",
         content:
           input && input.plan
             ? [{ type: "content", content: { type: "text", text: input.plan } }]
@@ -424,62 +434,20 @@ export function toolInfoFromToolUse(
   }
 }
 
-export function toolUpdateFromToolResult(toolResult: any, toolUse: any | undefined): ToolUpdate {
+type ToolResult = {
+  type: "tool_result";
+  content: any;
+  tool_use_id: string;
+  is_error: boolean;
+};
+
+export function toolUpdateFromToolResult(
+  toolResult: ToolResult,
+  toolUse: any | undefined,
+): ToolUpdate {
   switch (toolUse?.name) {
-    case "mcp__acp__edit":
-    case "edit":
-    case "Edit": {
-      // Parse the line numbers from the tool result
-      if (toolResult.content && toolResult.content.length > 0) {
-        try {
-          const firstContent = toolResult.content[0];
-          const data = JSON.parse(firstContent.text || firstContent);
-          if (data.lineNumbers && Array.isArray(data.lineNumbers)) {
-            const locations: ToolCallLocation[] = data.lineNumbers.map((line: number) => ({
-              path: toolUse?.input?.abs_path || toolUse?.input?.file_path,
-              line: line,
-            }));
-            return { locations };
-          }
-        } catch (error) {
-          console.error(`Error parsing edit tool result: ${error}`);
-          // If parsing fails, return empty object
-          return {};
-        }
-      }
-      return {};
-    }
-    case "mcp__acp__multi-edit":
-    case "multi-edit":
-    case "MultiEdit": {
-      // Parse the line numbers from the tool result
-      if (toolResult.content && toolResult.content.length > 0) {
-        try {
-          const firstContent = toolResult.content[0];
-          const data = JSON.parse(firstContent.text || firstContent);
-          if (data.lineNumbers && Array.isArray(data.lineNumbers)) {
-            const locations: ToolCallLocation[] = data.lineNumbers.map((line: number) => ({
-              path: toolUse?.input?.file_path || toolUse?.input?.abs_path,
-              line: line,
-            }));
-            return { locations };
-          }
-        } catch (error) {
-          console.error(`Error parsing edit tool result: ${error}`);
-
-          // If parsing fails, return empty object
-          return {};
-        }
-      }
-      return {};
-    }
-
-    case "mcp__acp__write":
-    case "Write":
-      return {};
-
     case "Read":
-    case "mcp__acp__read":
+    case toolNames.read:
       if (Array.isArray(toolResult.content) && toolResult.content.length > 0) {
         return {
           content: toolResult.content.map((content: any) => ({
@@ -508,9 +476,25 @@ export function toolUpdateFromToolResult(toolResult: any, toolUse: any | undefin
       }
       return {};
 
-    case "mcp__acp__Bash":
-      // The bash tool already embeds a terminal
+    case toolNames.bash:
+    case "edit":
+    case "Edit":
+    case toolNames.edit:
+    case toolNames.multiEdit:
+    case "multi-edit":
+    case "MultiEdit":
+    case toolNames.write:
+    case "Write": {
+      if (toolResult.is_error && toolResult.content?.length > 0) {
+        // Only return errors
+        return toAcpContentUpdate(toolResult.content);
+      }
       return {};
+    }
+
+    case "ExitPlanMode": {
+      return { title: "Exited Plan Mode" };
+    }
 
     case "Task":
     case "NotebookEdit":
@@ -527,31 +511,35 @@ export function toolUpdateFromToolResult(toolResult: any, toolUse: any | undefin
     case "WebSearch":
     case "Other":
     default: {
-      if (Array.isArray(toolResult.content) && toolResult.content.length > 0) {
-        return {
-          content: toolResult.content.map((content: any) => ({
-            type: "content",
-            content,
-          })),
-        };
-      } else if (typeof toolResult.content === "string" && toolResult.content.length > 0) {
-        return {
-          content: [
-            {
-              type: "content",
-              content: {
-                type: "text",
-                text: toolResult.content,
-              },
-            },
-          ],
-        };
-      }
-      return {};
+      return toAcpContentUpdate(toolResult.content);
     }
   }
 }
 
+function toAcpContentUpdate(content: any): { content?: ToolCallContent[] } {
+  if (Array.isArray(content) && content.length > 0) {
+    return {
+      content: content.map((content: any) => ({
+        type: "content",
+        content,
+      })),
+    };
+  } else if (typeof content === "string" && content.length > 0) {
+    return {
+      content: [
+        {
+          type: "content",
+          content: {
+            type: "text",
+            text: content,
+          },
+        },
+      ],
+    };
+  }
+  return {};
+}
+
 type ClaudePlanEntry = {
   content: string;
   status: "pending" | "in_progress" | "completed";

src/utils.ts

@@ -2,6 +2,8 @@
 
 import { Readable, Writable } from "node:stream";
 import { WritableStream, ReadableStream } from "node:stream/web";
+import { readFileSync } from "node:fs";
+import { platform } from "node:os";
 
 // Useful for bridging push-based and async-iterator-based code.
 export class Pushable<T> implements AsyncIterable<T> {
@@ -80,3 +82,43 @@ export function unreachable(value: never): never {
 export function sleep(time: number): Promise<void> {
   return new Promise((resolve) => setTimeout(resolve, time));
 }
+
+interface ManagedSettings {
+  permissions?: {
+    allow?: string[];
+    deny?: string[];
+  };
+  env?: Record<string, string>;
+}
+
+// Following the rules in https://docs.anthropic.com/en/docs/claude-code/settings#settings-files
+// This can be removed once the SDK supports it natively.
+function getManagedSettingsPath(): string {
+  const os = platform();
+  switch (os) {
+    case "darwin":
+      return "/Library/Application Support/ClaudeCode/managed-settings.json";
+    case "linux": // including WSL
+      return "/etc/claude-code/managed-settings.json";
+    case "win32":
+      return "C:\\ProgramData\\ClaudeCode\\managed-settings.json";
+    default:
+      return "/etc/claude-code/managed-settings.json";
+  }
+}
+
+export function loadManagedSettings(): ManagedSettings | null {
+  try {
+    return JSON.parse(readFileSync(getManagedSettingsPath(), "utf8")) as ManagedSettings;
+  } catch {
+    return null;
+  }
+}
+
+export function applyEnvironmentSettings(settings: ManagedSettings): void {
+  if (settings.env) {
+    for (const [key, value] of Object.entries(settings.env)) {
+      process.env[key] = value;
+    }
+  }
+}