fix: align SkillTool schema error output

src/services/tools/toolExecution.test.ts

@@ -1,7 +1,10 @@
 import { describe, expect, test } from 'bun:test'
 
 import { SkillTool } from '../../tools/SkillTool/SkillTool.js'
-import { getSchemaValidationErrorOverride } from './toolExecution.js'
+import {
+  getSchemaValidationErrorOverride,
+  getSchemaValidationToolUseResult,
+} from './toolExecution.js'
 
 describe('getSchemaValidationErrorOverride', () => {
   test('returns actionable missing-skill error for SkillTool', () => {
@@ -21,4 +24,10 @@ describe('getSchemaValidationErrorOverride', () => {
       getSchemaValidationErrorOverride(SkillTool, { skill: 'commit' }),
     ).toBe(null)
   })
+
+  test('uses the actionable override for structured toolUseResult too', () => {
+    expect(getSchemaValidationToolUseResult(SkillTool, {} as never)).toBe(
+      'InputValidationError: Missing skill name. Pass the slash command name as the skill parameter (e.g., skill: "commit" for /commit, skill: "review-pr" for /review-pr).',
+    )
+  })
 })

src/services/tools/toolExecution.ts

@@ -613,6 +613,15 @@ export function getSchemaValidationErrorOverride(
   return null
 }
 
+export function getSchemaValidationToolUseResult(
+  tool: Tool,
+  input: unknown,
+  fallbackMessage?: string,
+): string {
+  const override = getSchemaValidationErrorOverride(tool, input)
+  return `InputValidationError: ${override ?? fallbackMessage ?? ''}`
+}
+
 async function checkPermissionsAndCallTool(
   tool: Tool,
   toolUseID: string,
@@ -631,9 +640,9 @@ async function checkPermissionsAndCallTool(
   // Validate input types with zod (surprisingly, the model is not great at generating valid input)
   const parsedInput = tool.inputSchema.safeParse(input)
   if (!parsedInput.success) {
+    const fallbackErrorContent = formatZodValidationError(tool.name, parsedInput.error)
     let errorContent =
-      getSchemaValidationErrorOverride(tool, input) ??
-      formatZodValidationError(tool.name, parsedInput.error)
+      getSchemaValidationErrorOverride(tool, input) ?? fallbackErrorContent
 
     const schemaHint = buildSchemaNotSentHint(
       tool,
@@ -691,7 +700,11 @@ async function checkPermissionsAndCallTool(
               tool_use_id: toolUseID,
             },
           ],
-          toolUseResult: `InputValidationError: ${parsedInput.error.message}`,
+          toolUseResult: getSchemaValidationToolUseResult(
+            tool,
+            input,
+            parsedInput.error.message,
+          ),
           sourceToolAssistantUUID: assistantMessage.uuid,
         }),
       },