Steering implementation (#309)

* Steering implementation

Author: Rizzen

examples/steering.ts

@@ -0,0 +1,13 @@
+{
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": ".",
+    "declaration": false,
+    "declarationMap": false,
+    "sourceMap": false
+  },
+  "include": [
+    "steering.ts"
+  ],
+  "exclude": []
+}

examples/tsconfig.json

@@ -33,11 +33,13 @@
     "package:win-x64": "cd dist/bin && zip codex-acp-x64-windows.zip codex-acp-x64-windows.exe",
     "package:win-arm64": "cd dist/bin && zip codex-acp-arm64-windows.zip codex-acp-arm64-windows.exe",
     "start": "node --import tsx src/index.ts",
+    "example:steering": "node --import tsx examples/steering.ts",
+    "example:steering:multistep": "node --import tsx examples/steering.ts",
     "generate-types": "./node_modules/.bin/codex app-server generate-ts --out src/app-server",
     "test": "vitest run",
     "test:e2e": "npm run build && RUN_E2E_TESTS=true vitest run src/__tests__/CodexACPAgent/e2e",
     "test:watch": "vitest",
-    "typecheck": "tsc --noEmit",
+    "typecheck": "tsc --noEmit && tsc --noEmit -p examples/tsconfig.json",
     "codex-test": "tsx .claude/skills/run-codex/scripts/run-codex-test.ts"
   },
   "homepage": "https://github.com/agentclientprotocol/codex-acp#readme",

package.json

@@ -1,12 +1,14 @@
 import type {
     ClientContext,
+    ContentBlock,
     LoadSessionResponse,
     NewSessionResponse,
     ResumeSessionResponse,
     SessionId,
 } from "@agentclientprotocol/sdk";
 
 export const LEGACY_SET_SESSION_MODEL_METHOD = "session/set_model";
+export const SESSION_STEERING_METHOD = "_session/steering";
 export const GOAL_CONTROL_METHOD = "_codex/session/goal_control";
 
 export type LegacySessionModel = {
@@ -43,13 +45,15 @@ export type ExtMethodRequest =
     AuthenticationStatusRequest
     | AuthenticationLogoutRequest
     | LegacySetSessionModelExtRequest
+    | SessionSteeringExtRequest
     | GoalControlExtRequest
 
 export function isExtMethodRequest(request: { method: string, params: Record<string, unknown> }): request is ExtMethodRequest {
     return request.method === "authentication/status"
         || request.method === "authentication/logout"
         || request.method === LEGACY_SET_SESSION_MODEL_METHOD
-        || request.method === GOAL_CONTROL_METHOD;
+        || request.method === GOAL_CONTROL_METHOD
+        || request.method === SESSION_STEERING_METHOD;
 }
 
 export type AuthenticationStatusRequest = { method: "authentication/status", params: {} }
@@ -79,3 +83,24 @@ export async function legacySetSessionModel(
 ): Promise<LegacySetSessionModelResponse> {
     return await connection.request<LegacySetSessionModelResponse, LegacySetSessionModelRequest>(LEGACY_SET_SESSION_MODEL_METHOD, params);
 }
+
+export type SessionSteerRequest = {
+    sessionId: SessionId;
+    prompt: ContentBlock[];
+}
+
+export type SessionSteeringResponse = {
+    outcome: "injected" | "startedNewTurn" | "failed";
+}
+
+export type SessionSteeringExtRequest = {
+    method: typeof SESSION_STEERING_METHOD;
+    params: SessionSteerRequest;
+}
+
+export async function steerSessionWithFallback(
+    connection: Pick<ClientContext, "request">,
+    params: SessionSteerRequest,
+): Promise<SessionSteeringResponse> {
+    return await connection.request<SessionSteeringResponse, SessionSteerRequest>(SESSION_STEERING_METHOD, params);
+}

src/AcpExtensions.ts

@@ -37,6 +37,7 @@ import type {
     ThreadGoalStatus,
     ThreadSourceKind,
     TurnCompletedNotification,
+    TurnSteerResponse,
     UserInput,
 } from "./app-server/v2";
 import packageJson from "../package.json";
@@ -844,6 +845,14 @@ export class CodexAcpClient {
         });
     }
 
+    async steerTurn(params: { threadId: string, turnId: string, prompt: acp.ContentBlock[] }): Promise<TurnSteerResponse> {
+        return await this.codexClient.turnSteer({
+            threadId: params.threadId,
+            expectedTurnId: params.turnId,
+            input: buildPromptItems(params.prompt),
+        });
+    }
+
     async fetchAvailableModels(): Promise<Model[]> {
         const models: Model[] = [];
         let cursor: string | null = null;