refactor: split acp mappers

src/acp/event-mapper.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, it } from "vitest";
+
+import { extractAttachmentsFromPrompt, extractTextFromPrompt } from "./event-mapper.js";
+
+describe("acp event mapper", () => {
+  it("extracts text and resource blocks into prompt text", () => {
+    const text = extractTextFromPrompt([
+      { type: "text", text: "Hello" },
+      { type: "resource", resource: { text: "File contents" } },
+      { type: "resource_link", uri: "https://example.com", title: "Spec" },
+      { type: "image", data: "abc", mimeType: "image/png" },
+    ]);
+
+    expect(text).toBe(
+      "Hello\nFile contents\n[Resource link (Spec)] https://example.com",
+    );
+  });
+
+  it("extracts image blocks into gateway attachments", () => {
+    const attachments = extractAttachmentsFromPrompt([
+      { type: "image", data: "abc", mimeType: "image/png" },
+      { type: "image", data: "", mimeType: "image/png" },
+      { type: "text", text: "ignored" },
+    ]);
+
+    expect(attachments).toEqual([
+      {
+        type: "image",
+        mimeType: "image/png",
+        content: "abc",
+      },
+    ]);
+  });
+});

src/acp/event-mapper.ts

@@ -0,0 +1,73 @@
+import type { ContentBlock, ImageContent, ToolKind } from "@agentclientprotocol/sdk";
+
+export type GatewayAttachment = {
+  type: string;
+  mimeType: string;
+  content: string;
+};
+
+export function extractTextFromPrompt(prompt: ContentBlock[]): string {
+  const parts: string[] = [];
+  for (const block of prompt) {
+    if (block.type === "text") {
+      parts.push(block.text);
+      continue;
+    }
+    if (block.type === "resource") {
+      const resource = block.resource as { text?: string } | undefined;
+      if (resource?.text) parts.push(resource.text);
+      continue;
+    }
+    if (block.type === "resource_link") {
+      const title = block.title ? ` (${block.title})` : "";
+      const uri = block.uri ?? "";
+      const line = uri ? `[Resource link${title}] ${uri}` : `[Resource link${title}]`;
+      parts.push(line);
+    }
+  }
+  return parts.join("\n");
+}
+
+export function extractAttachmentsFromPrompt(prompt: ContentBlock[]): GatewayAttachment[] {
+  const attachments: GatewayAttachment[] = [];
+  for (const block of prompt) {
+    if (block.type !== "image") continue;
+    const image = block as ImageContent;
+    if (!image.data || !image.mimeType) continue;
+    attachments.push({
+      type: "image",
+      mimeType: image.mimeType,
+      content: image.data,
+    });
+  }
+  return attachments;
+}
+
+export function formatToolTitle(
+  name: string | undefined,
+  args: Record<string, unknown> | undefined,
+): string {
+  const base = name ?? "tool";
+  if (!args || Object.keys(args).length === 0) return base;
+  const parts = Object.entries(args).map(([key, value]) => {
+    const raw = typeof value === "string" ? value : JSON.stringify(value);
+    const safe = raw.length > 100 ? `${raw.slice(0, 100)}...` : raw;
+    return `${key}: ${safe}`;
+  });
+  return `${base}: ${parts.join(", ")}`;
+}
+
+export function inferToolKind(name?: string): ToolKind | undefined {
+  if (!name) return "other";
+  const normalized = name.toLowerCase();
+  if (normalized.includes("read")) return "read";
+  if (normalized.includes("write") || normalized.includes("edit")) return "edit";
+  if (normalized.includes("delete") || normalized.includes("remove")) return "delete";
+  if (normalized.includes("move") || normalized.includes("rename")) return "move";
+  if (normalized.includes("search") || normalized.includes("find")) return "search";
+  if (normalized.includes("exec") || normalized.includes("run") || normalized.includes("bash")) {
+    return "execute";
+  }
+  if (normalized.includes("fetch") || normalized.includes("http")) return "fetch";
+  return "other";
+}

src/acp/index.ts

@@ -1,2 +1,4 @@
 export { serveAcpGateway } from "./server.js";
+export { createInMemorySessionStore } from "./session.js";
+export type { AcpSessionStore } from "./session.js";
 export type { AcpServerOptions } from "./types.js";

src/acp/meta.ts

@@ -0,0 +1,35 @@
+export function readString(
+  meta: Record<string, unknown> | null | undefined,
+  keys: string[],
+): string | undefined {
+  if (!meta) return undefined;
+  for (const key of keys) {
+    const value = meta[key];
+    if (typeof value === "string" && value.trim()) return value.trim();
+  }
+  return undefined;
+}
+
+export function readBool(
+  meta: Record<string, unknown> | null | undefined,
+  keys: string[],
+): boolean | undefined {
+  if (!meta) return undefined;
+  for (const key of keys) {
+    const value = meta[key];
+    if (typeof value === "boolean") return value;
+  }
+  return undefined;
+}
+
+export function readNumber(
+  meta: Record<string, unknown> | null | undefined,
+  keys: string[],
+): number | undefined {
+  if (!meta) return undefined;
+  for (const key of keys) {
+    const value = meta[key];
+    if (typeof value === "number" && Number.isFinite(value)) return value;
+  }
+  return undefined;
+}

src/acp/session-mapper.test.ts

@@ -0,0 +1,57 @@
+import { describe, expect, it, vi } from "vitest";
+
+import type { GatewayClient } from "../gateway/client.js";
+import { parseSessionMeta, resolveSessionKey } from "./session-mapper.js";
+
+function createGateway(resolveLabelKey = "agent:main:label"): {
+  gateway: GatewayClient;
+  request: ReturnType<typeof vi.fn>;
+} {
+  const request = vi.fn(async (method: string, params: Record<string, unknown>) => {
+    if (method === "sessions.resolve" && "label" in params) {
+      return { ok: true, key: resolveLabelKey };
+    }
+    if (method === "sessions.resolve" && "key" in params) {
+      return { ok: true, key: params.key as string };
+    }
+    return { ok: true };
+  });
+
+  return {
+    gateway: { request } as unknown as GatewayClient,
+    request,
+  };
+}
+
+describe("acp session mapper", () => {
+  it("prefers explicit sessionLabel over sessionKey", async () => {
+    const { gateway, request } = createGateway();
+    const meta = parseSessionMeta({ sessionLabel: "support", sessionKey: "agent:main:main" });
+
+    const key = await resolveSessionKey({
+      meta,
+      fallbackKey: "acp:fallback",
+      gateway,
+      opts: {},
+    });
+
+    expect(key).toBe("agent:main:label");
+    expect(request).toHaveBeenCalledTimes(1);
+    expect(request).toHaveBeenCalledWith("sessions.resolve", { label: "support" });
+  });
+
+  it("lets meta sessionKey override default label", async () => {
+    const { gateway, request } = createGateway();
+    const meta = parseSessionMeta({ sessionKey: "agent:main:override" });
+
+    const key = await resolveSessionKey({
+      meta,
+      fallbackKey: "acp:fallback",
+      gateway,
+      opts: { defaultSessionLabel: "default-label" },
+    });
+
+    expect(key).toBe("agent:main:override");
+    expect(request).not.toHaveBeenCalled();
+  });
+});

src/acp/session-mapper.ts

@@ -0,0 +1,95 @@
+import type { GatewayClient } from "../gateway/client.js";
+
+import type { AcpServerOptions } from "./types.js";
+import { readBool, readString } from "./meta.js";
+
+export type AcpSessionMeta = {
+  sessionKey?: string;
+  sessionLabel?: string;
+  resetSession?: boolean;
+  requireExisting?: boolean;
+  prefixCwd?: boolean;
+};
+
+export function parseSessionMeta(meta: unknown): AcpSessionMeta {
+  if (!meta || typeof meta !== "object") return {};
+  const record = meta as Record<string, unknown>;
+  return {
+    sessionKey: readString(record, ["sessionKey", "session", "key"]),
+    sessionLabel: readString(record, ["sessionLabel", "label"]),
+    resetSession: readBool(record, ["resetSession", "reset"]),
+    requireExisting: readBool(record, ["requireExistingSession", "requireExisting"]),
+    prefixCwd: readBool(record, ["prefixCwd"]),
+  };
+}
+
+export async function resolveSessionKey(params: {
+  meta: AcpSessionMeta;
+  fallbackKey: string;
+  gateway: GatewayClient;
+  opts: AcpServerOptions;
+}): Promise<string> {
+  const requestedLabel = params.meta.sessionLabel ?? params.opts.defaultSessionLabel;
+  const requestedKey = params.meta.sessionKey ?? params.opts.defaultSessionKey;
+  const requireExisting =
+    params.meta.requireExisting ?? params.opts.requireExistingSession ?? false;
+
+  if (params.meta.sessionLabel) {
+    const resolved = await params.gateway.request<{ ok: true; key: string }>(
+      "sessions.resolve",
+      { label: params.meta.sessionLabel },
+    );
+    if (!resolved?.key) {
+      throw new Error(`Unable to resolve session label: ${params.meta.sessionLabel}`);
+    }
+    return resolved.key;
+  }
+
+  if (params.meta.sessionKey) {
+    if (!requireExisting) return params.meta.sessionKey;
+    const resolved = await params.gateway.request<{ ok: true; key: string }>(
+      "sessions.resolve",
+      { key: params.meta.sessionKey },
+    );
+    if (!resolved?.key) {
+      throw new Error(`Session key not found: ${params.meta.sessionKey}`);
+    }
+    return resolved.key;
+  }
+
+  if (requestedLabel) {
+    const resolved = await params.gateway.request<{ ok: true; key: string }>(
+      "sessions.resolve",
+      { label: requestedLabel },
+    );
+    if (!resolved?.key) {
+      throw new Error(`Unable to resolve session label: ${requestedLabel}`);
+    }
+    return resolved.key;
+  }
+
+  if (requestedKey) {
+    if (!requireExisting) return requestedKey;
+    const resolved = await params.gateway.request<{ ok: true; key: string }>(
+      "sessions.resolve",
+      { key: requestedKey },
+    );
+    if (!resolved?.key) {
+      throw new Error(`Session key not found: ${requestedKey}`);
+    }
+    return resolved.key;
+  }
+
+  return params.fallbackKey;
+}
+
+export async function resetSessionIfNeeded(params: {
+  meta: AcpSessionMeta;
+  sessionKey: string;
+  gateway: GatewayClient;
+  opts: AcpServerOptions;
+}): Promise<void> {
+  const resetSession = params.meta.resetSession ?? params.opts.resetSession ?? false;
+  if (!resetSession) return;
+  await params.gateway.request("sessions.reset", { key: params.sessionKey });
+}

src/acp/session.test.ts

@@ -1,30 +1,26 @@
 import { describe, expect, it, afterEach } from "vitest";
 
-import {
-  cancelActiveRun,
-  clearAllSessionsForTest,
-  createSession,
-  getSessionByRunId,
-  setActiveRun,
-} from "./session.js";
+import { createInMemorySessionStore } from "./session.js";
 
 describe("acp session manager", () => {
+  const store = createInMemorySessionStore();
+
   afterEach(() => {
-    clearAllSessionsForTest();
+    store.clearAllSessionsForTest();
   });
 
   it("tracks active runs and clears on cancel", () => {
-    const session = createSession({
+    const session = store.createSession({
       sessionKey: "acp:test",
       cwd: "/tmp",
     });
     const controller = new AbortController();
-    setActiveRun(session.sessionId, "run-1", controller);
+    store.setActiveRun(session.sessionId, "run-1", controller);
 
-    expect(getSessionByRunId("run-1")?.sessionId).toBe(session.sessionId);
+    expect(store.getSessionByRunId("run-1")?.sessionId).toBe(session.sessionId);
 
-    const cancelled = cancelActiveRun(session.sessionId);
+    const cancelled = store.cancelActiveRun(session.sessionId);
     expect(cancelled).toBe(true);
-    expect(getSessionByRunId("run-1")).toBeUndefined();
+    expect(store.getSessionByRunId("run-1")).toBeUndefined();
   });
 });

src/acp/session.ts

@@ -2,70 +2,92 @@ import { randomUUID } from "node:crypto";
 
 import type { AcpSession } from "./types.js";
 
-const sessions = new Map<string, AcpSession>();
-const runIdToSessionId = new Map<string, string>();
+export type AcpSessionStore = {
+  createSession: (params: {
+    sessionKey: string;
+    cwd: string;
+    sessionId?: string;
+  }) => AcpSession;
+  getSession: (sessionId: string) => AcpSession | undefined;
+  getSessionByRunId: (runId: string) => AcpSession | undefined;
+  setActiveRun: (sessionId: string, runId: string, abortController: AbortController) => void;
+  clearActiveRun: (sessionId: string) => void;
+  cancelActiveRun: (sessionId: string) => boolean;
+  clearAllSessionsForTest: () => void;
+};
 
-export function createSession(params: {
-  sessionKey: string;
-  cwd: string;
-  sessionId?: string;
-}): AcpSession {
-  const sessionId = params.sessionId ?? randomUUID();
-  const session: AcpSession = {
-    sessionId,
-    sessionKey: params.sessionKey,
-    cwd: params.cwd,
-    createdAt: Date.now(),
-    abortController: null,
-    activeRunId: null,
+export function createInMemorySessionStore(): AcpSessionStore {
+  const sessions = new Map<string, AcpSession>();
+  const runIdToSessionId = new Map<string, string>();
+
+  const createSession: AcpSessionStore["createSession"] = (params) => {
+    const sessionId = params.sessionId ?? randomUUID();
+    const session: AcpSession = {
+      sessionId,
+      sessionKey: params.sessionKey,
+      cwd: params.cwd,
+      createdAt: Date.now(),
+      abortController: null,
+      activeRunId: null,
+    };
+    sessions.set(sessionId, session);
+    return session;
+  };
+
+  const getSession: AcpSessionStore["getSession"] = (sessionId) => sessions.get(sessionId);
+
+  const getSessionByRunId: AcpSessionStore["getSessionByRunId"] = (runId) => {
+    const sessionId = runIdToSessionId.get(runId);
+    return sessionId ? sessions.get(sessionId) : undefined;
+  };
+
+  const setActiveRun: AcpSessionStore["setActiveRun"] = (
+    sessionId,
+    runId,
+    abortController,
+  ) => {
+    const session = sessions.get(sessionId);
+    if (!session) return;
+    session.activeRunId = runId;
+    session.abortController = abortController;
+    runIdToSessionId.set(runId, sessionId);
+  };
+
+  const clearActiveRun: AcpSessionStore["clearActiveRun"] = (sessionId) => {
+    const session = sessions.get(sessionId);
+    if (!session) return;
+    if (session.activeRunId) runIdToSessionId.delete(session.activeRunId);
+    session.activeRunId = null;
+    session.abortController = null;
+  };
+
+  const cancelActiveRun: AcpSessionStore["cancelActiveRun"] = (sessionId) => {
+    const session = sessions.get(sessionId);
+    if (!session?.abortController) return false;
+    session.abortController.abort();
+    if (session.activeRunId) runIdToSessionId.delete(session.activeRunId);
+    session.abortController = null;
+    session.activeRunId = null;
+    return true;
+  };
+
+  const clearAllSessionsForTest: AcpSessionStore["clearAllSessionsForTest"] = () => {
+    for (const session of sessions.values()) {
+      session.abortController?.abort();
+    }
+    sessions.clear();
+    runIdToSessionId.clear();
+  };
+
+  return {
+    createSession,
+    getSession,
+    getSessionByRunId,
+    setActiveRun,
+    clearActiveRun,
+    cancelActiveRun,
+    clearAllSessionsForTest,
   };
-  sessions.set(sessionId, session);
-  return session;
 }
 
-export function getSession(sessionId: string): AcpSession | undefined {
-  return sessions.get(sessionId);
-}
-
-export function getSessionByRunId(runId: string): AcpSession | undefined {
-  const sessionId = runIdToSessionId.get(runId);
-  return sessionId ? sessions.get(sessionId) : undefined;
-}
-
-export function setActiveRun(
-  sessionId: string,
-  runId: string,
-  abortController: AbortController,
-): void {
-  const session = sessions.get(sessionId);
-  if (!session) return;
-  session.activeRunId = runId;
-  session.abortController = abortController;
-  runIdToSessionId.set(runId, sessionId);
-}
-
-export function clearActiveRun(sessionId: string): void {
-  const session = sessions.get(sessionId);
-  if (!session) return;
-  if (session.activeRunId) runIdToSessionId.delete(session.activeRunId);
-  session.activeRunId = null;
-  session.abortController = null;
-}
-
-export function cancelActiveRun(sessionId: string): boolean {
-  const session = sessions.get(sessionId);
-  if (!session?.abortController) return false;
-  session.abortController.abort();
-  if (session.activeRunId) runIdToSessionId.delete(session.activeRunId);
-  session.abortController = null;
-  session.activeRunId = null;
-  return true;
-}
-
-export function clearAllSessionsForTest(): void {
-  for (const session of sessions.values()) {
-    session.abortController?.abort();
-  }
-  sessions.clear();
-  runIdToSessionId.clear();
-}
+export const defaultAcpSessionStore = createInMemorySessionStore();

src/acp/translator.ts

@@ -6,8 +6,6 @@ import type {
   AuthenticateRequest,
   AuthenticateResponse,
   CancelNotification,
-  ContentBlock,
-  ImageContent,
   InitializeRequest,
   InitializeResponse,
   ListSessionsRequest,
@@ -21,21 +19,22 @@ import type {
   SetSessionModeRequest,
   SetSessionModeResponse,
   StopReason,
-  ToolKind,
 } from "@agentclientprotocol/sdk";
 import { PROTOCOL_VERSION } from "@agentclientprotocol/sdk";
 
 import type { GatewayClient } from "../gateway/client.js";
 import type { EventFrame } from "../gateway/protocol/index.js";
 import type { SessionsListResult } from "../gateway/session-utils.js";
-import { ACP_AGENT_INFO, type AcpServerOptions } from "./types.js";
+import { readBool, readNumber, readString } from "./meta.js";
 import {
-  cancelActiveRun,
-  clearActiveRun,
-  createSession,
-  getSession,
-  setActiveRun,
-} from "./session.js";
+  extractAttachmentsFromPrompt,
+  extractTextFromPrompt,
+  formatToolTitle,
+  inferToolKind,
+} from "./event-mapper.js";
+import { parseSessionMeta, resetSessionIfNeeded, resolveSessionKey } from "./session-mapper.js";
+import { ACP_AGENT_INFO, type AcpServerOptions } from "./types.js";
+import { defaultAcpSessionStore, type AcpSessionStore } from "./session.js";
 
 type PendingPrompt = {
   sessionId: string;
@@ -48,25 +47,22 @@ type PendingPrompt = {
   toolCalls?: Set<string>;
 };
 
-type SessionMeta = {
-  sessionKey?: string;
-  sessionLabel?: string;
-  resetSession?: boolean;
-  requireExisting?: boolean;
-  prefixCwd?: boolean;
+type AcpGatewayAgentOptions = AcpServerOptions & {
+  sessionStore?: AcpSessionStore;
 };
 
 export class AcpGatewayAgent implements Agent {
   private connection: AgentSideConnection;
   private gateway: GatewayClient;
-  private opts: AcpServerOptions;
+  private opts: AcpGatewayAgentOptions;
   private log: (msg: string) => void;
+  private sessionStore: AcpSessionStore;
   private pendingPrompts = new Map<string, PendingPrompt>();
 
   constructor(
     connection: AgentSideConnection,
     gateway: GatewayClient,
-    opts: AcpServerOptions = {},
+    opts: AcpGatewayAgentOptions = {},
   ) {
     this.connection = connection;
     this.gateway = gateway;
@@ -74,6 +70,7 @@ export class AcpGatewayAgent implements Agent {
     this.log = opts.verbose
       ? (msg: string) => process.stderr.write(`[acp] ${msg}\n`)
       : () => {};
+    this.sessionStore = opts.sessionStore ?? defaultAcpSessionStore;
   }
 
   start(): void {
@@ -88,7 +85,7 @@ export class AcpGatewayAgent implements Agent {
     this.log(`gateway disconnected: ${reason}`);
     for (const pending of this.pendingPrompts.values()) {
       pending.reject(new Error(`Gateway disconnected: ${reason}`));
-      clearActiveRun(pending.sessionId);
+      this.sessionStore.clearActiveRun(pending.sessionId);
     }
     this.pendingPrompts.clear();
   }
@@ -132,11 +129,21 @@ export class AcpGatewayAgent implements Agent {
     }
 
     const sessionId = randomUUID();
-    const meta = this.parseSessionMeta(params._meta);
-    const sessionKey = await this.resolveSessionKey(meta, `acp:${sessionId}`);
-    await this.resetSessionIfNeeded(meta, sessionKey);
+    const meta = parseSessionMeta(params._meta);
+    const sessionKey = await resolveSessionKey({
+      meta,
+      fallbackKey: `acp:${sessionId}`,
+      gateway: this.gateway,
+      opts: this.opts,
+    });
+    await resetSessionIfNeeded({
+      meta,
+      sessionKey,
+      gateway: this.gateway,
+      opts: this.opts,
+    });
 
-    const session = createSession({
+    const session = this.sessionStore.createSession({
       sessionId,
       sessionKey,
       cwd: params.cwd,
@@ -150,11 +157,21 @@ export class AcpGatewayAgent implements Agent {
       this.log(`ignoring ${params.mcpServers.length} MCP servers`);
     }
 
-    const meta = this.parseSessionMeta(params._meta);
-    const sessionKey = await this.resolveSessionKey(meta, params.sessionId);
-    await this.resetSessionIfNeeded(meta, sessionKey);
+    const meta = parseSessionMeta(params._meta);
+    const sessionKey = await resolveSessionKey({
+      meta,
+      fallbackKey: params.sessionId,
+      gateway: this.gateway,
+      opts: this.opts,
+    });
+    await resetSessionIfNeeded({
+      meta,
+      sessionKey,
+      gateway: this.gateway,
+      opts: this.opts,
+    });
 
-    const session = createSession({
+    const session = this.sessionStore.createSession({
       sessionId: params.sessionId,
       sessionKey,
       cwd: params.cwd,
@@ -190,7 +207,7 @@ export class AcpGatewayAgent implements Agent {
   async setSessionMode(
     params: SetSessionModeRequest,
   ): Promise<SetSessionModeResponse | void> {
-    const session = getSession(params.sessionId);
+    const session = this.sessionStore.getSession(params.sessionId);
     if (!session) {
       throw new Error(`Session ${params.sessionId} not found`);
     }
@@ -208,22 +225,22 @@ export class AcpGatewayAgent implements Agent {
   }
 
   async prompt(params: PromptRequest): Promise<PromptResponse> {
-    const session = getSession(params.sessionId);
+    const session = this.sessionStore.getSession(params.sessionId);
     if (!session) {
       throw new Error(`Session ${params.sessionId} not found`);
     }
 
     if (session.abortController) {
-      cancelActiveRun(params.sessionId);
+      this.sessionStore.cancelActiveRun(params.sessionId);
     }
 
     const abortController = new AbortController();
     const runId = randomUUID();
-    setActiveRun(params.sessionId, runId, abortController);
+    this.sessionStore.setActiveRun(params.sessionId, runId, abortController);
 
-    const meta = this.parseSessionMeta(params._meta);
-    const userText = this.extractTextFromPrompt(params.prompt);
-    const attachments = this.extractAttachmentsFromPrompt(params.prompt);
+    const meta = parseSessionMeta(params._meta);
+    const userText = extractTextFromPrompt(params.prompt);
+    const attachments = extractAttachmentsFromPrompt(params.prompt);
     const prefixCwd = meta.prefixCwd ?? this.opts.prefixCwd ?? true;
     const message = prefixCwd ? `[Working directory: ${session.cwd}]\n\n${userText}` : userText;
 
@@ -252,17 +269,17 @@ export class AcpGatewayAgent implements Agent {
         )
         .catch((err) => {
           this.pendingPrompts.delete(params.sessionId);
-          clearActiveRun(params.sessionId);
+          this.sessionStore.clearActiveRun(params.sessionId);
           reject(err instanceof Error ? err : new Error(String(err)));
         });
     });
   }
 
   async cancel(params: CancelNotification): Promise<void> {
-    const session = getSession(params.sessionId);
+    const session = this.sessionStore.getSession(params.sessionId);
     if (!session) return;
 
-    cancelActiveRun(params.sessionId);
+    this.sessionStore.cancelActiveRun(params.sessionId);
     try {
       await this.gateway.request("chat.abort", { sessionKey: session.sessionKey });
     } catch (err) {
@@ -389,7 +406,7 @@ export class AcpGatewayAgent implements Agent {
     stopReason: StopReason,
   ): void {
     this.pendingPrompts.delete(sessionId);
-    clearActiveRun(sessionId);
+    this.sessionStore.clearActiveRun(sessionId);
     pending.resolve({ stopReason });
   }
 
@@ -400,157 +417,4 @@ export class AcpGatewayAgent implements Agent {
     return undefined;
   }
 
-  private extractTextFromPrompt(prompt: ContentBlock[]): string {
-    const parts: string[] = [];
-    for (const block of prompt) {
-      if (block.type === "text") {
-        parts.push(block.text);
-        continue;
-      }
-      if (block.type === "resource") {
-        const resource = block.resource as { text?: string } | undefined;
-        if (resource?.text) parts.push(resource.text);
-        continue;
-      }
-      if (block.type === "resource_link") {
-        const title = block.title ? ` (${block.title})` : "";
-        const uri = block.uri ?? "";
-        const line = uri ? `[Resource link${title}] ${uri}` : `[Resource link${title}]`;
-        parts.push(line);
-      }
-    }
-    return parts.join("\n");
-  }
-
-  private extractAttachmentsFromPrompt(
-    prompt: ContentBlock[],
-  ): Array<{ type: string; mimeType: string; content: string }> {
-    const attachments: Array<{ type: string; mimeType: string; content: string }> = [];
-    for (const block of prompt) {
-      if (block.type !== "image") continue;
-      const image = block as ImageContent;
-      if (!image.data || !image.mimeType) continue;
-      attachments.push({
-        type: "image",
-        mimeType: image.mimeType,
-        content: image.data,
-      });
-    }
-    return attachments;
-  }
-
-  private parseSessionMeta(meta: unknown): SessionMeta {
-    if (!meta || typeof meta !== "object") return {};
-    const record = meta as Record<string, unknown>;
-    return {
-      sessionKey: readString(record, ["sessionKey", "session", "key"]),
-      sessionLabel: readString(record, ["sessionLabel", "label"]),
-      resetSession: readBool(record, ["resetSession", "reset"]),
-      requireExisting: readBool(record, ["requireExistingSession", "requireExisting"]),
-      prefixCwd: readBool(record, ["prefixCwd"]),
-    };
-  }
-
-  private async resolveSessionKey(meta: SessionMeta, fallbackKey: string): Promise<string> {
-    const requestedKey = meta.sessionKey ?? this.opts.defaultSessionKey;
-    const requestedLabel = meta.sessionLabel ?? this.opts.defaultSessionLabel;
-    const requireExisting =
-      meta.requireExisting ?? this.opts.requireExistingSession ?? false;
-
-    if (requestedLabel) {
-      const resolved = await this.gateway.request<{ ok: true; key: string }>(
-        "sessions.resolve",
-        { label: requestedLabel },
-      );
-      if (!resolved?.key) {
-        throw new Error(`Unable to resolve session label: ${requestedLabel}`);
-      }
-      return resolved.key;
-    }
-
-    if (requestedKey) {
-      if (!requireExisting) return requestedKey;
-      const resolved = await this.gateway.request<{ ok: true; key: string }>(
-        "sessions.resolve",
-        { key: requestedKey },
-      );
-      if (!resolved?.key) {
-        throw new Error(`Session key not found: ${requestedKey}`);
-      }
-      return resolved.key;
-    }
-
-    return fallbackKey;
-  }
-
-  private async resetSessionIfNeeded(meta: SessionMeta, sessionKey: string): Promise<void> {
-    const resetSession = meta.resetSession ?? this.opts.resetSession ?? false;
-    if (!resetSession) return;
-    await this.gateway.request("sessions.reset", { key: sessionKey });
-  }
-}
-
-function readString(
-  meta: Record<string, unknown> | null | undefined,
-  keys: string[],
-): string | undefined {
-  if (!meta) return undefined;
-  for (const key of keys) {
-    const value = meta[key];
-    if (typeof value === "string" && value.trim()) return value.trim();
-  }
-  return undefined;
-}
-
-function readBool(
-  meta: Record<string, unknown> | null | undefined,
-  keys: string[],
-): boolean | undefined {
-  if (!meta) return undefined;
-  for (const key of keys) {
-    const value = meta[key];
-    if (typeof value === "boolean") return value;
-  }
-  return undefined;
-}
-
-function readNumber(
-  meta: Record<string, unknown> | null | undefined,
-  keys: string[],
-): number | undefined {
-  if (!meta) return undefined;
-  for (const key of keys) {
-    const value = meta[key];
-    if (typeof value === "number" && Number.isFinite(value)) return value;
-  }
-  return undefined;
-}
-
-function formatToolTitle(
-  name: string | undefined,
-  args: Record<string, unknown> | undefined,
-): string {
-  const base = name ?? "tool";
-  if (!args || Object.keys(args).length === 0) return base;
-  const parts = Object.entries(args).map(([key, value]) => {
-    const raw = typeof value === "string" ? value : JSON.stringify(value);
-    const safe = raw.length > 100 ? `${raw.slice(0, 100)}...` : raw;
-    return `${key}: ${safe}`;
-  });
-  return `${base}: ${parts.join(", ")}`;
-}
-
-function inferToolKind(name?: string): ToolKind | undefined {
-  if (!name) return "other";
-  const normalized = name.toLowerCase();
-  if (normalized.includes("read")) return "read";
-  if (normalized.includes("write") || normalized.includes("edit")) return "edit";
-  if (normalized.includes("delete") || normalized.includes("remove")) return "delete";
-  if (normalized.includes("move") || normalized.includes("rename")) return "move";
-  if (normalized.includes("search") || normalized.includes("find")) return "search";
-  if (normalized.includes("exec") || normalized.includes("run") || normalized.includes("bash")) {
-    return "execute";
-  }
-  if (normalized.includes("fetch") || normalized.includes("http")) return "fetch";
-  return "other";
 }

src/routing/session-key.ts

@@ -1,3 +1,15 @@
+import {
+  parseAgentSessionKey,
+  type ParsedAgentSessionKey,
+} from "../sessions/session-key-utils.js";
+
+export {
+  isAcpSessionKey,
+  isSubagentSessionKey,
+  parseAgentSessionKey,
+  type ParsedAgentSessionKey,
+} from "../sessions/session-key-utils.js";
+
 export const DEFAULT_AGENT_ID = "main";
 export const DEFAULT_MAIN_KEY = "main";
 export const DEFAULT_ACCOUNT_ID = "default";
@@ -11,11 +23,6 @@ export function normalizeMainKey(value: string | undefined | null): string {
   return trimmed ? trimmed : DEFAULT_MAIN_KEY;
 }
 
-export type ParsedAgentSessionKey = {
-  agentId: string;
-  rest: string;
-};
-
 export function toAgentRequestSessionKey(storeKey: string | undefined | null): string | undefined {
   const raw = (storeKey ?? "").trim();
   if (!raw) return undefined;
@@ -70,37 +77,6 @@ export function normalizeAccountId(value: string | undefined | null): string {
   );
 }
 
-export function parseAgentSessionKey(
-  sessionKey: string | undefined | null,
-): ParsedAgentSessionKey | null {
-  const raw = (sessionKey ?? "").trim();
-  if (!raw) return null;
-  const parts = raw.split(":").filter(Boolean);
-  if (parts.length < 3) return null;
-  if (parts[0] !== "agent") return null;
-  const agentId = parts[1]?.trim();
-  const rest = parts.slice(2).join(":");
-  if (!agentId || !rest) return null;
-  return { agentId, rest };
-}
-
-export function isSubagentSessionKey(sessionKey: string | undefined | null): boolean {
-  const raw = (sessionKey ?? "").trim();
-  if (!raw) return false;
-  if (raw.toLowerCase().startsWith("subagent:")) return true;
-  const parsed = parseAgentSessionKey(raw);
-  return Boolean((parsed?.rest ?? "").toLowerCase().startsWith("subagent:"));
-}
-
-export function isAcpSessionKey(sessionKey: string | undefined | null): boolean {
-  const raw = (sessionKey ?? "").trim();
-  if (!raw) return false;
-  const normalized = raw.toLowerCase();
-  if (normalized.startsWith("acp:")) return true;
-  const parsed = parseAgentSessionKey(raw);
-  return Boolean((parsed?.rest ?? "").toLowerCase().startsWith("acp:"));
-}
-
 export function buildAgentMainSessionKey(params: {
   agentId: string;
   mainKey?: string | undefined;

src/sessions/session-key-utils.ts

@@ -0,0 +1,35 @@
+export type ParsedAgentSessionKey = {
+  agentId: string;
+  rest: string;
+};
+
+export function parseAgentSessionKey(
+  sessionKey: string | undefined | null,
+): ParsedAgentSessionKey | null {
+  const raw = (sessionKey ?? "").trim();
+  if (!raw) return null;
+  const parts = raw.split(":").filter(Boolean);
+  if (parts.length < 3) return null;
+  if (parts[0] !== "agent") return null;
+  const agentId = parts[1]?.trim();
+  const rest = parts.slice(2).join(":");
+  if (!agentId || !rest) return null;
+  return { agentId, rest };
+}
+
+export function isSubagentSessionKey(sessionKey: string | undefined | null): boolean {
+  const raw = (sessionKey ?? "").trim();
+  if (!raw) return false;
+  if (raw.toLowerCase().startsWith("subagent:")) return true;
+  const parsed = parseAgentSessionKey(raw);
+  return Boolean((parsed?.rest ?? "").toLowerCase().startsWith("subagent:"));
+}
+
+export function isAcpSessionKey(sessionKey: string | undefined | null): boolean {
+  const raw = (sessionKey ?? "").trim();
+  if (!raw) return false;
+  const normalized = raw.toLowerCase();
+  if (normalized.startsWith("acp:")) return true;
+  const parsed = parseAgentSessionKey(raw);
+  return Boolean((parsed?.rest ?? "").toLowerCase().startsWith("acp:"));
+}