From e7a94984ea3abc2912627d0b0f91c8c854c423c4 Mon Sep 17 00:00:00 2001
From: Mikel Lindsaar <mikel@lindsaar.net>
Date: Fri, 30 Jan 2026 20:48:41 +1100
Subject: [PATCH] fix: respect supportsReasoningEffort compat flag for
 reasoning models

---
 CHANGELOG.md                                 |  3 ++
 src/agents/pi-embedded-runner/compact.ts     |  2 +-
 src/agents/pi-embedded-runner/run/attempt.ts |  2 +-
 src/agents/pi-embedded-runner/utils.test.ts  | 37 ++++++++++++++++++++
 src/agents/pi-embedded-runner/utils.ts       | 12 ++++++-
 5 files changed, 53 insertions(+), 3 deletions(-)
 create mode 100644 src/agents/pi-embedded-runner/utils.test.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4c0549c16..c0dd93d60 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,9 @@ Docs: https://docs.openclaw.ai
 ## 2026.1.29
 Status: stable.
 
+### Fixed
+- Fixed reasoning models that don't support the `reasoning_effort` parameter (like XAI's `grok-4-1-fast-reasoning`) by respecting the `supportsReasoningEffort` compat flag in model configurations
+
 ### Changes
 - Rebrand: rename the npm package/CLI to `openclaw`, add a `openclaw` compatibility shim, and move extensions to the `@openclaw/*` scope.
 - Onboarding: strengthen security warning copy for beta + access control expectations.
diff --git a/src/agents/pi-embedded-runner/compact.ts b/src/agents/pi-embedded-runner/compact.ts
index 2dc4c5325..a70cc0e87 100644
--- a/src/agents/pi-embedded-runner/compact.ts
+++ b/src/agents/pi-embedded-runner/compact.ts
@@ -390,7 +390,7 @@ export async function compactEmbeddedPiSessionDirect(
         authStorage,
         modelRegistry,
         model,
-        thinkingLevel: mapThinkingLevel(params.thinkLevel),
+        thinkingLevel: mapThinkingLevel(params.thinkLevel, model.compat),
         systemPrompt,
         tools: builtInTools,
         customTools,
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index e83c3ae4a..1bab121e6 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -453,7 +453,7 @@ export async function runEmbeddedAttempt(
         authStorage: params.authStorage,
         modelRegistry: params.modelRegistry,
         model: params.model,
-        thinkingLevel: mapThinkingLevel(params.thinkLevel),
+        thinkingLevel: mapThinkingLevel(params.thinkLevel, params.model.compat),
         systemPrompt,
         tools: builtInTools,
         customTools: allCustomTools,
diff --git a/src/agents/pi-embedded-runner/utils.test.ts b/src/agents/pi-embedded-runner/utils.test.ts
new file mode 100644
index 000000000..e4e89bc94
--- /dev/null
+++ b/src/agents/pi-embedded-runner/utils.test.ts
@@ -0,0 +1,37 @@
+import { describe, expect, it } from "vitest";
+import type { ModelCompatConfig } from "../../config/types.models.js";
+import { mapThinkingLevel } from "./utils.js";
+
+describe("mapThinkingLevel", () => {
+  it("returns undefined when model doesn't support reasoning_effort", () => {
+    const compat: ModelCompatConfig = { supportsReasoningEffort: false };
+    expect(mapThinkingLevel("low", compat)).toBeUndefined();
+    expect(mapThinkingLevel("high", compat)).toBeUndefined();
+    expect(mapThinkingLevel("off", compat)).toBeUndefined();
+    expect(mapThinkingLevel(undefined, compat)).toBeUndefined();
+  });
+
+  it("returns level when model supports reasoning_effort", () => {
+    const compat: ModelCompatConfig = { supportsReasoningEffort: true };
+    expect(mapThinkingLevel("low", compat)).toBe("low");
+    expect(mapThinkingLevel("high", compat)).toBe("high");
+    expect(mapThinkingLevel("off", compat)).toBe("off");
+  });
+
+  it("returns level when compat is empty object", () => {
+    const compat: ModelCompatConfig = {};
+    expect(mapThinkingLevel("low", compat)).toBe("low");
+    expect(mapThinkingLevel("high", compat)).toBe("high");
+  });
+
+  it("returns level when compat is undefined", () => {
+    expect(mapThinkingLevel("low")).toBe("low");
+    expect(mapThinkingLevel("high")).toBe("high");
+  });
+
+  it("handles undefined level with no compat restrictions", () => {
+    expect(mapThinkingLevel(undefined)).toBe("off");
+    expect(mapThinkingLevel(undefined, {})).toBe("off");
+    expect(mapThinkingLevel(undefined, { supportsReasoningEffort: true })).toBe("off");
+  });
+});
diff --git a/src/agents/pi-embedded-runner/utils.ts b/src/agents/pi-embedded-runner/utils.ts
index a95c18330..e4ac10a44 100644
--- a/src/agents/pi-embedded-runner/utils.ts
+++ b/src/agents/pi-embedded-runner/utils.ts
@@ -1,9 +1,19 @@
 import type { ThinkingLevel } from "@mariozechner/pi-agent-core";
 import type { ReasoningLevel, ThinkLevel } from "../../auto-reply/thinking.js";
 import type { OpenClawConfig } from "../../config/config.js";
+import type { ModelCompatConfig } from "../../config/types.models.js";
 import type { ExecToolDefaults } from "../bash-tools.js";
 
-export function mapThinkingLevel(level?: ThinkLevel): ThinkingLevel {
+export function mapThinkingLevel(
+  level: ThinkLevel | undefined,
+  modelCompat?: ModelCompatConfig,
+): ThinkingLevel | undefined {
+  // If model doesn't support reasoning_effort parameter, return undefined
+  // so the SDK doesn't pass it to the API
+  if (modelCompat?.supportsReasoningEffort === false) {
+    return undefined;
+  }
+
   // pi-agent-core supports "xhigh"; OpenClaw enables it for specific models.
   if (!level) return "off";
   return level;