feat(sdk): codex thread-goal wrappers (thread/goal/set|get|clear) (#147)

## Summary
- Follow-up to #146: adds `setThreadGoal()`, `getThreadGoal()`, and
`clearThreadGoal()` to `CodexAxonConnection`, wrapping
`thread/goal/set`, `thread/goal/get`, and `thread/goal/clear`.
- Same explicit-wrapper shape as the #146 methods; thread-scoped with
the standard `not_connected` guard; types were already vendored in the
generated v2 bindings.
- Backs a downstream `/goal` slash command.

## Test plan
- Wire-level assertions for all three methods (threadId injection,
params passthrough) and `not_connected` rejection tests. Full suite: 579
tests pass; typecheck and biome clean.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: ross-rl

sdk/src/codex/connection.test.ts

@@ -198,6 +198,9 @@ describe("CodexAxonConnection", () => {
     await conn.setThreadName("renamed");
     await conn.listMcpServerStatus();
     await conn.listSkills({ forceReload: true });
+    await conn.setThreadGoal({ objective: "ship it" });
+    await conn.getThreadGoal();
+    await conn.clearThreadGoal();
     const frames = mock.axon.publish.mock.calls.map(([event]) => JSON.parse(event.payload));
     const byMethod = Object.fromEntries(frames.map((frame) => [frame.method, frame]));
     // Option<()> wire params: the field must be absent, not an empty object.
@@ -211,13 +214,23 @@ describe("CodexAxonConnection", () => {
     });
     expect(byMethod["mcpServerStatus/list"]).toMatchObject({ params: {} });
     expect(byMethod["skills/list"]).toMatchObject({ params: { forceReload: true } });
+    expect(byMethod["thread/goal/set"]).toMatchObject({
+      params: { threadId: "thr-1", objective: "ship it" },
+    });
+    expect(byMethod["thread/goal/get"]).toMatchObject({ params: { threadId: "thr-1" } });
+    expect(byMethod["thread/goal/clear"]).toMatchObject({ params: { threadId: "thr-1" } });
   });
 
   it("rejects thread-scoped wrappers before a thread exists", async () => {
     const { conn } = setup();
     await conn.connect();
     await expect(conn.readThread()).rejects.toMatchObject({ code: "not_connected" });
     await expect(conn.setThreadName("nope")).rejects.toMatchObject({ code: "not_connected" });
+    await expect(conn.setThreadGoal({ objective: "x" })).rejects.toMatchObject({
+      code: "not_connected",
+    });
+    await expect(conn.getThreadGoal()).rejects.toMatchObject({ code: "not_connected" });
+    await expect(conn.clearThreadGoal()).rejects.toMatchObject({ code: "not_connected" });
   });
 
   it("correlates responses by JSON-RPC id", async () => {

sdk/src/codex/connection.ts

@@ -34,6 +34,10 @@ import type {
   ServerRequest,
   SkillsListParams,
   SkillsListResponse,
+  ThreadGoalClearResponse,
+  ThreadGoalGetResponse,
+  ThreadGoalSetParams,
+  ThreadGoalSetResponse,
   ThreadReadParams,
   ThreadReadResponse,
   ThreadSetNameResponse,
@@ -605,6 +609,42 @@ export class CodexAxonConnection {
       name,
     })) as ThreadSetNameResponse;
   }
+  /** Sets or updates the active thread's goal (`thread/goal/set`). */
+  async setThreadGoal(
+    params: Omit<ThreadGoalSetParams, "threadId">,
+  ): Promise<ThreadGoalSetResponse> {
+    if (!this._threadId)
+      throw new ConnectionStateError(
+        "not_connected",
+        "No active thread. Call startThread() first.",
+      );
+    return (await this.request("thread/goal/set", {
+      ...params,
+      threadId: this._threadId,
+    })) as ThreadGoalSetResponse;
+  }
+  /** Reads the active thread's goal (`thread/goal/get`). */
+  async getThreadGoal(): Promise<ThreadGoalGetResponse> {
+    if (!this._threadId)
+      throw new ConnectionStateError(
+        "not_connected",
+        "No active thread. Call startThread() first.",
+      );
+    return (await this.request("thread/goal/get", {
+      threadId: this._threadId,
+    })) as ThreadGoalGetResponse;
+  }
+  /** Clears the active thread's goal (`thread/goal/clear`). */
+  async clearThreadGoal(): Promise<ThreadGoalClearResponse> {
+    if (!this._threadId)
+      throw new ConnectionStateError(
+        "not_connected",
+        "No active thread. Call startThread() first.",
+      );
+    return (await this.request("thread/goal/clear", {
+      threadId: this._threadId,
+    })) as ThreadGoalClearResponse;
+  }
   /** Lists configured MCP servers with startup/auth status (`mcpServerStatus/list`). */
   async listMcpServerStatus(
     params: ListMcpServerStatusParams = {},

sdk/src/codex/protocol/index.ts

@@ -12,6 +12,10 @@ export type {
   ReviewTarget,
   SkillsListParams,
   SkillsListResponse,
+  ThreadGoalClearResponse,
+  ThreadGoalGetResponse,
+  ThreadGoalSetParams,
+  ThreadGoalSetResponse,
   ThreadReadParams,
   ThreadReadResponse,
   ThreadSetNameParams,