From 83bfb6dbd8ca94e42ee8de718fa23ff90c1acee1 Mon Sep 17 00:00:00 2001
From: roboomp <omp@can.ac>
Date: Sat, 18 Jul 2026 04:11:26 +0000
Subject: [PATCH] fix(task): avoided boolean output subschemas

Represent task output schema inputs as explicit JSON-compatible types so ArkType emits object-form subschemas accepted by llama.cpp grammar generation.

Fixes #5957
---
 packages/coding-agent/CHANGELOG.md            |  4 ++++
 packages/coding-agent/src/task/types.ts       | 19 +++++++++++--------
 .../coding-agent/test/task/task-batch.test.ts |  2 ++
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index ad20be261..161776971 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed `task` tool schemas emitting boolean subschemas that llama.cpp grammar generation cannot parse ([#5957](https://github.com/can1357/oh-my-pi/issues/5957)).
+
 ## [17.0.3] - 2026-07-17
 
 ### Changed
diff --git a/packages/coding-agent/src/task/types.ts b/packages/coding-agent/src/task/types.ts
index e6d2aad6f..62007fd3d 100644
--- a/packages/coding-agent/src/task/types.ts
+++ b/packages/coding-agent/src/task/types.ts
@@ -106,11 +106,14 @@ export interface SubagentLifecyclePayload {
 /** Display cap for a normalized one-line label (roster line, registry `displayName`, prompt field). */
 export const LABEL_MAX = 80;
 
+// Keep this explicit: ArkType serializes `unknown` as a boolean subschema, which llama.cpp grammars reject.
+const outputSchemaInputSchema = type("object | boolean | string | null");
+
 export const taskItemSchema = type({
 	"name?": "string",
 	agent: "string = 'task'",
 	task: "string",
-	"outputSchema?": "unknown",
+	"outputSchema?": outputSchemaInputSchema,
 	"schemaMode?": '"permissive" | "strict"',
 	"+": "delete",
 });
@@ -118,7 +121,7 @@ const taskItemSchemaIsolated = type({
 	"name?": "string",
 	agent: "string = 'task'",
 	task: "string",
-	"outputSchema?": "unknown",
+	"outputSchema?": outputSchemaInputSchema,
 	"schemaMode?": '"permissive" | "strict"',
 	"isolated?": "boolean",
 	"+": "delete",
@@ -144,7 +147,7 @@ export const taskSchema = type({
 	"name?": "string",
 	agent: "string = 'task'",
 	task: "string",
-	"outputSchema?": "unknown",
+	"outputSchema?": outputSchemaInputSchema,
 	"schemaMode?": '"permissive" | "strict"',
 	"isolated?": "boolean",
 	"+": "delete",
@@ -153,7 +156,7 @@ const taskSchemaNoIsolation = type({
 	"name?": "string",
 	agent: "string = 'task'",
 	task: "string",
-	"outputSchema?": "unknown",
+	"outputSchema?": outputSchemaInputSchema,
 	"schemaMode?": '"permissive" | "strict"',
 	"+": "delete",
 });
@@ -197,7 +200,7 @@ function createTaskSchema(options: {
 				"name?": "string",
 				agent,
 				task: "string",
-				"outputSchema?": "unknown",
+				"outputSchema?": outputSchemaInputSchema,
 				"schemaMode?": '"permissive" | "strict"',
 				"isolated?": "boolean",
 				"+": "delete",
@@ -212,7 +215,7 @@ function createTaskSchema(options: {
 			"name?": "string",
 			agent,
 			task: "string",
-			"outputSchema?": "unknown",
+			"outputSchema?": outputSchemaInputSchema,
 			"schemaMode?": '"permissive" | "strict"',
 			"+": "delete",
 		});
@@ -227,7 +230,7 @@ function createTaskSchema(options: {
 			"name?": "string",
 			agent,
 			task: "string",
-			"outputSchema?": "unknown",
+			"outputSchema?": outputSchemaInputSchema,
 			"schemaMode?": '"permissive" | "strict"',
 			"isolated?": "boolean",
 			"+": "delete",
@@ -237,7 +240,7 @@ function createTaskSchema(options: {
 		"name?": "string",
 		agent,
 		task: "string",
-		"outputSchema?": "unknown",
+		"outputSchema?": outputSchemaInputSchema,
 		"schemaMode?": '"permissive" | "strict"',
 		"+": "delete",
 	});
diff --git a/packages/coding-agent/test/task/task-batch.test.ts b/packages/coding-agent/test/task/task-batch.test.ts
index 019dd4ef2..9af6cb447 100644
--- a/packages/coding-agent/test/task/task-batch.test.ts
+++ b/packages/coding-agent/test/task/task-batch.test.ts
@@ -102,6 +102,7 @@ describe("task.batch schema gating", () => {
 		expect(offProperties.task).toBeDefined();
 		expect(offProperties.name).toBeDefined();
 		expect(offProperties.outputSchema).toBeDefined();
+		expect(typeof offProperties.outputSchema).toBe("object");
 		expect(offProperties.schemaMode).toBeDefined();
 
 		const on = await TaskTool.create(createSession({ settings: { "task.batch": true } }));
@@ -120,6 +121,7 @@ describe("task.batch schema gating", () => {
 		expect(items?.properties?.name).toBeDefined();
 		expect(items?.properties?.agent).toBeDefined();
 		expect(items?.properties?.outputSchema).toBeDefined();
+		expect(typeof items?.properties?.outputSchema).toBe("object");
 		expect(items?.properties?.schemaMode).toBeDefined();
 	});