fix(coding-agent): ignore unknown skill frontmatter fields

AGENTS.md

@@ -24,6 +24,7 @@ read README.md, then ask which module(s) to work on. Based on the answer, read t
 - Note: `npm run check` does not run tests.
 - NEVER run: `npm run dev`, `npm run build`, `npm test`
 - Only run specific tests if user instructs: `npm test -- test/specific.test.ts`
+- Run tests from the package root, not the repo root.
 - When writing tests, run them, identify issues in either the test or implementation, and iterate until fixed.
 - NEVER commit unless user asks
 

packages/coding-agent/CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Fixed
 
+- Ignored unknown skill frontmatter fields when loading skills
 - Fixed `/reload` not picking up changes in global settings.json ([#1241](https://github.com/badlogic/pi-mono/issues/1241))
 - Fixed Unix bash detection to fall back to PATH lookup when `/bin/bash` is unavailable, including Termux setups ([#1230](https://github.com/badlogic/pi-mono/pull/1230) by [@VaclavSynacek](https://github.com/VaclavSynacek))
 

packages/coding-agent/docs/skills.md

@@ -176,7 +176,8 @@ Pi validates skills against the Agent Skills standard. Most issues produce warni
 - Name exceeds 64 characters or contains invalid characters
 - Name starts/ends with hyphen or has consecutive hyphens
 - Description exceeds 1024 characters
-- Unknown frontmatter fields
+
+Unknown frontmatter fields are ignored.
 
 **Exception:** Skills with missing description are not loaded.
 

packages/coding-agent/src/core/skills.ts

@@ -5,20 +5,6 @@ import { CONFIG_DIR_NAME, getAgentDir } from "../config.js";
 import { parseFrontmatter } from "../utils/frontmatter.js";
 import type { ResourceDiagnostic } from "./diagnostics.js";
 
-/**
- * Standard frontmatter fields per Agent Skills spec.
- * See: https://agentskills.io/specification#frontmatter-required
- */
-const ALLOWED_FRONTMATTER_FIELDS = new Set([
-	"name",
-	"description",
-	"license",
-	"compatibility",
-	"metadata",
-	"allowed-tools",
-	"disable-model-invocation",
-]);
-
 /** Max name length per spec */
 const MAX_NAME_LENGTH = 64;
 
@@ -91,19 +77,6 @@ function validateDescription(description: string | undefined): string[] {
 	return errors;
 }
 
-/**
- * Check for unknown frontmatter fields.
- */
-function validateFrontmatterFields(keys: string[]): string[] {
-	const errors: string[] = [];
-	for (const key of keys) {
-		if (!ALLOWED_FRONTMATTER_FIELDS.has(key)) {
-			errors.push(`unknown frontmatter field "${key}"`);
-		}
-	}
-	return errors;
-}
-
 export interface LoadSkillsFromDirOptions {
 	/** Directory to scan for skills */
 	dir: string;
@@ -197,16 +170,9 @@ function loadSkillFromFile(
 	try {
 		const rawContent = readFileSync(filePath, "utf-8");
 		const { frontmatter } = parseFrontmatter<SkillFrontmatter>(rawContent);
-		const allKeys = Object.keys(frontmatter);
 		const skillDir = dirname(filePath);
 		const parentDirName = basename(skillDir);
 
-		// Validate frontmatter fields
-		const fieldErrors = validateFrontmatterFields(allKeys);
-		for (const error of fieldErrors) {
-			diagnostics.push({ type: "warning", message: error, path: filePath });
-		}
-
 		// Validate description
 		const descErrors = validateDescription(frontmatter.description);
 		for (const error of descErrors) {

packages/coding-agent/test/skills.test.ts

@@ -65,19 +65,14 @@ describe("skills", () => {
 			expect(diagnostics.some((d: ResourceDiagnostic) => d.message.includes("description is required"))).toBe(true);
 		});
 
-		it("should warn when unknown frontmatter fields are present", () => {
+		it("should ignore unknown frontmatter fields", () => {
 			const { skills, diagnostics } = loadSkillsFromDir({
 				dir: join(fixturesDir, "unknown-field"),
 				source: "test",
 			});
 
 			expect(skills).toHaveLength(1);
-			expect(
+			expect(diagnostics).toHaveLength(0);
-				diagnostics.some((d: ResourceDiagnostic) => d.message.includes('unknown frontmatter field "author"')),
-			).toBe(true);
-			expect(
-				diagnostics.some((d: ResourceDiagnostic) => d.message.includes('unknown frontmatter field "version"')),
-			).toBe(true);
 		});
 
 		it("should load nested skills recursively", () => {