fix: handle missing skill parameter in SkillTool (#485)

* fix: handle missing skill parameter in SkillTool

* fix: preserve SkillTool schema contract

* fix: align SkillTool schema error output

src/services/tools/toolExecution.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, test } from 'bun:test'
+
+import { SkillTool } from '../../tools/SkillTool/SkillTool.js'
+import {
+  getSchemaValidationErrorOverride,
+  getSchemaValidationToolUseResult,
+} from './toolExecution.js'
+
+describe('getSchemaValidationErrorOverride', () => {
+  test('returns actionable missing-skill error for SkillTool', () => {
+    expect(getSchemaValidationErrorOverride(SkillTool, {})).toBe(
+      'Missing skill name. Pass the slash command name as the skill parameter (e.g., skill: "commit" for /commit, skill: "review-pr" for /review-pr).',
+    )
+  })
+
+  test('does not override unrelated tool schema failures', () => {
+    expect(getSchemaValidationErrorOverride({ name: 'Read' } as never, {})).toBe(
+      null,
+    )
+  })
+
+  test('does not override SkillTool when skill is present', () => {
+    expect(
+      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).',
+    )
+  })
+})