fix(agent): preserve in-process MCP server across session refresh

packages/agent/src/adapters/claude/claude-agent.refresh.test.ts

@@ -83,7 +83,14 @@ function installFakeSession(
       sessionId,
       cwd: "/tmp/repo",
       model: "claude-sonnet-4-6",
-      mcpServers: { posthog: { type: "http", url: "https://old" } },
+      mcpServers: {
+        posthog: { type: "http", url: "https://old" },
+        "posthog-code-tools": {
+          type: "sdk",
+          name: "posthog-code-tools",
+          instance: {},
+        },
+      },
       abortController,
     },
     input,
@@ -222,7 +229,8 @@ describe("ClaudeAcpAgent.extMethod refresh_session", () => {
     expect(oldQuery.interrupt).toHaveBeenCalledTimes(1);
     expect(endSpy).toHaveBeenCalledTimes(1);
 
-    // New query was built with resume identity (not sessionId) and new servers
+    // New query: resume identity (not sessionId), http server refreshed, and
+    // the in-process local-tools server preserved.
     expect(lastQueryCall.options).toMatchObject({
       resume: "s-2",
       forkSession: false,
@@ -232,6 +240,11 @@ describe("ClaudeAcpAgent.extMethod refresh_session", () => {
           url: "https://fresh",
           headers: { "x-foo": "bar" },
         },
+        "posthog-code-tools": {
+          type: "sdk",
+          name: "posthog-code-tools",
+          instance: {},
+        },
       },
     });
     expect(lastQueryCall.options?.sessionId).toBeUndefined();
@@ -313,4 +326,25 @@ describe("ClaudeAcpAgent.extMethod refresh_session", () => {
     expect(fetchMcpToolMetadataMock).toHaveBeenCalledTimes(1);
     expect(fetchMcpToolMetadataMock.mock.calls[0][0]).toBe(createdQueries[0]);
   });
+
+  it("preserves the in-process local-tools server across refresh", async () => {
+    const agent = makeAgent();
+    installFakeSession(agent, "s-inprocess");
+
+    // freshMcpServers carries only external (http) servers, so the sdk server
+    // must be carried over from the previous session options.
+    await agent.extMethod(POSTHOG_METHODS.REFRESH_SESSION, {
+      mcpServers: freshMcpServers,
+    });
+
+    const servers = lastQueryCall.options?.mcpServers as Record<
+      string,
+      { type?: string }
+    >;
+    expect(servers["posthog-code-tools"]).toEqual({
+      type: "sdk",
+      name: "posthog-code-tools",
+      instance: {},
+    });
+  });
 });

packages/agent/src/adapters/claude/claude-agent.ts

@@ -1111,9 +1111,18 @@ export class ClaudeAcpAgent extends BaseAcpAgent {
     // fresh AbortController.
     const newAbortController = new AbortController();
     const { sessionId: _drop, ...rest } = prev.queryOptions;
+
+    // parseMcpServers yields only http/sse/stdio — carry over any in-process
+    // ("sdk") server so the local-tools server (signed commits) survives.
+    const preservedInProcess = Object.fromEntries(
+      Object.entries(prev.queryOptions.mcpServers ?? {}).filter(
+        ([, cfg]) => (cfg as { type?: string }).type === "sdk",
+      ),
+    );
+
     const newOptions: Options = {
       ...rest,
-      mcpServers,
+      mcpServers: { ...mcpServers, ...preservedInProcess },
       resume: this.sessionId,
       forkSession: false,
       abortController: newAbortController,