diff --git a/packages/agent/src/adapters/claude/claude-agent.resume-model.test.ts b/packages/agent/src/adapters/claude/claude-agent.resume-model.test.ts
index 04610b6f00..41d5be45d5 100644
--- a/packages/agent/src/adapters/claude/claude-agent.resume-model.test.ts
+++ b/packages/agent/src/adapters/claude/claude-agent.resume-model.test.ts
@@ -84,6 +84,12 @@ function getModelConfigOption(response: {
   return response.configOptions?.find((opt) => opt.id === "model");
 }
 
+function getEffortConfigOption(response: {
+  configOptions?: Array<{ id: string; currentValue?: unknown }> | null;
+}) {
+  return response.configOptions?.find((opt) => opt.id === "effort");
+}
+
 // Real temp dirs: createSession validates cwd and SettingsManager reads
 // settings from disk; CLAUDE_CONFIG_DIR keeps both away from the real home.
 const cwd = mkdtempSync(path.join(os.tmpdir(), "claude-agent-test-cwd-"));
@@ -358,6 +364,21 @@ describe("ClaudeAcpAgent session creation", () => {
     }
   });
 
+  it("does not expose effort controls when a new session starts with Kimi K3", async () => {
+    const agent = makeAgent();
+
+    const response = await agent.newSession({
+      cwd,
+      mcpServers: [],
+      _meta: { taskRunId: "run-kimi", model: "moonshotai/kimi-k3" },
+    });
+
+    expect(getModelConfigOption(response)?.currentValue).toBe(
+      "moonshotai/kimi-k3",
+    );
+    expect(getEffortConfigOption(response)).toBeUndefined();
+  });
+
   // The timeout *message* (RequestError "... timed out after ...") is covered
   // by claude-agent.refresh.test.ts. Here we cover the leak fix on the
   // new-session and resume paths: any init failure must close the query so the
diff --git a/packages/agent/src/adapters/claude/claude-agent.ts b/packages/agent/src/adapters/claude/claude-agent.ts
index 14974dd3c6..0a9842dee7 100644
--- a/packages/agent/src/adapters/claude/claude-agent.ts
+++ b/packages/agent/src/adapters/claude/claude-agent.ts
@@ -2252,6 +2252,7 @@ export class ClaudeAcpAgent extends BaseAcpAgent {
       settingsManager.getSettings().model,
       meta?.model,
     ]);
+    modelOptions.currentModelId = resolvedModelId;
     session.modelId = resolvedModelId;
     session.lastContextWindowSize =
       this.getContextWindowForModel(resolvedModelId);