fix: dynamic frontmatter field extraction from role schema

Replace hardcoded 5-field candidate with schema-driven extraction.
Now reads outputSchema properties and picks matching fields from
parsed frontmatter, supporting role-specific fields like plan,
approved, success.

Falls back to standard 5 fields when schema has no properties.

Fixes #388

小橘 <xiaoju@shazhou.work>

packages/workflow-agent-kit/__tests__/frontmatter-fast-path.test.ts

@@ -29,6 +29,27 @@ const STRICT_SCHEMA = {
   additionalProperties: false,
 };
 
+/** Role-specific schema (reviewer) — only approved, no standard agent fields. */
+const REVIEWER_SCHEMA = {
+  type: "object",
+  properties: {
+    approved: { type: "boolean" },
+  },
+  required: ["approved"],
+  additionalProperties: false,
+};
+
+/** Role-specific schema (planner) — custom status enum + plan hash. */
+const PLANNER_SCHEMA = {
+  type: "object",
+  properties: {
+    status: { type: "string", enum: ["ready", "insufficient_info"] },
+    plan: { type: "string" },
+  },
+  required: ["status"],
+  additionalProperties: false,
+};
+
 async function makeStoreWithSchema(schema: Record<string, unknown>) {
   const store = createMemoryStore();
   const schemaHash = await putSchema(store, schema);
@@ -134,3 +155,48 @@ describe("tryFrontmatterFastPath — fallback: schema mismatch", () => {
     expect(result).toBeNull();
   });
 });
+
+// ── Role-specific schema fields ───────────────────────────────────────────────
+
+describe("tryFrontmatterFastPath — role-specific fields", () => {
+  test("extracts approved only for reviewer schema (no extra standard fields)", async () => {
+    const { store, schemaHash } = await makeStoreWithSchema(REVIEWER_SCHEMA);
+
+    const raw = "---\napproved: true\n---\n\nReview passed.";
+
+    const result = await tryFrontmatterFastPath(raw, schemaHash, store);
+    expect(result).not.toBeNull();
+
+    const node = store.get(result!.outputHash);
+    expect(node).not.toBeNull();
+    const payload = node!.payload as Record<string, unknown>;
+    expect(payload).toEqual({ approved: true });
+    expect(payload.status).toBeUndefined();
+    expect(payload.scope).toBeUndefined();
+  });
+
+  test("extracts plan and role-specific status for planner schema", async () => {
+    const { store, schemaHash } = await makeStoreWithSchema(PLANNER_SCHEMA);
+
+    const raw = "---\nstatus: ready\nplan: 01HASHPLANNER0001\n---\n\nSpec summary.";
+
+    const result = await tryFrontmatterFastPath(raw, schemaHash, store);
+    expect(result).not.toBeNull();
+
+    const node = store.get(result!.outputHash);
+    expect(node).not.toBeNull();
+    const payload = node!.payload as Record<string, unknown>;
+    expect(payload.status).toBe("ready");
+    expect(payload.plan).toBe("01HASHPLANNER0001");
+    expect(payload.scope).toBeUndefined();
+  });
+
+  test("returns null when required role-specific field is missing", async () => {
+    const { store, schemaHash } = await makeStoreWithSchema(REVIEWER_SCHEMA);
+
+    const raw = "---\nstatus: done\nscope: role\n---\n\nBody.";
+
+    const result = await tryFrontmatterFastPath(raw, schemaHash, store);
+    expect(result).toBeNull();
+  });
+});

packages/workflow-agent-kit/src/build-output-format-instruction.ts

@@ -9,7 +9,7 @@ import type { JSONSchema } from "@uncaged/json-cas";
  *
  * Returns an empty array for schemas with no inspectable property definitions.
  */
-function extractSchemaFields(schema: JSONSchema): string[] {
+export function extractSchemaFields(schema: JSONSchema): string[] {
   if (typeof schema.properties === "object" && schema.properties !== null) {
     return Object.keys(schema.properties as Record<string, unknown>);
   }

packages/workflow-agent-kit/src/frontmatter.ts

@@ -1,13 +1,139 @@
 import type { Store } from "@uncaged/json-cas";
-import { validate } from "@uncaged/json-cas";
+import { getSchema, validate } from "@uncaged/json-cas";
 import type { CasRef } from "@uncaged/workflow-protocol";
-import { parseFrontmatterMarkdown, validateFrontmatter } from "@uncaged/workflow-util";
+import {
+  type AgentFrontmatter,
+  createLogger,
+  parseFrontmatterMarkdown,
+  validateFrontmatter,
+} from "@uncaged/workflow-util";
+import { parse as parseYaml } from "yaml";
+
+import { extractSchemaFields } from "./build-output-format-instruction.js";
+
+const log = createLogger({ sink: { kind: "stderr" } });
+
+const STANDARD_KEYS = ["status", "next", "confidence", "artifacts", "scope"] as const;
+
+type StandardKey = (typeof STANDARD_KEYS)[number];
 
 export type FrontmatterFastPathResult = {
   body: string;
   outputHash: CasRef;
 };
 
+function extractYamlBlock(raw: string): string | null {
+  const fence = "---";
+  if (!raw.startsWith(fence)) {
+    return null;
+  }
+
+  const rest = raw.slice(fence.length);
+  if (rest.length > 0 && rest[0] !== "\n" && rest[0] !== "\r") {
+    return null;
+  }
+
+  const afterOpen = rest.startsWith("\n") ? rest.slice(1) : rest;
+  const closeIndex = afterOpen.indexOf(`\n${fence}`);
+  if (closeIndex === -1) {
+    return null;
+  }
+
+  return afterOpen.slice(0, closeIndex);
+}
+
+function parseRawFrontmatterFields(raw: string): Record<string, unknown> {
+  const yamlText = extractYamlBlock(raw);
+  if (yamlText === null) {
+    return {};
+  }
+
+  try {
+    const parsed = parseYaml(yamlText);
+    if (typeof parsed !== "object" || parsed === null || Array.isArray(parsed)) {
+      return {};
+    }
+    return parsed as Record<string, unknown>;
+  } catch {
+    return {};
+  }
+}
+
+function defaultCandidate(frontmatter: AgentFrontmatter): Record<string, unknown> {
+  return {
+    status: frontmatter.status,
+    next: frontmatter.next,
+    confidence: frontmatter.confidence,
+    artifacts: [...frontmatter.artifacts],
+    scope: frontmatter.scope,
+  };
+}
+
+function pickStandardField(frontmatter: AgentFrontmatter, key: StandardKey): unknown {
+  switch (key) {
+    case "status":
+      return frontmatter.status;
+    case "next":
+      return frontmatter.next;
+    case "confidence":
+      return frontmatter.confidence;
+    case "artifacts":
+      return [...frontmatter.artifacts];
+    case "scope":
+      return frontmatter.scope;
+  }
+}
+
+function isStandardKey(key: string): key is StandardKey {
+  return (STANDARD_KEYS as readonly string[]).includes(key);
+}
+
+function pickFieldValue(
+  field: string,
+  frontmatter: AgentFrontmatter,
+  rawFields: Record<string, unknown>,
+): unknown | undefined {
+  if (!isStandardKey(field)) {
+    return Object.hasOwn(rawFields, field) ? rawFields[field] : undefined;
+  }
+
+  const coerced = pickStandardField(frontmatter, field);
+  if (field === "artifacts" || field === "scope") {
+    return coerced;
+  }
+  if (coerced !== null) {
+    return coerced;
+  }
+  return Object.hasOwn(rawFields, field) ? rawFields[field] : coerced;
+}
+
+/**
+ * Build a CAS candidate object from schema property keys and parsed frontmatter.
+ *
+ * When the schema has no inspectable properties, falls back to the five standard
+ * agent frontmatter fields for backward compatibility.
+ */
+function buildCandidate(
+  frontmatter: AgentFrontmatter,
+  rawFields: Record<string, unknown>,
+  schemaFields: string[],
+): Record<string, unknown> {
+  if (schemaFields.length === 0) {
+    return defaultCandidate(frontmatter);
+  }
+
+  const candidate: Record<string, unknown> = {};
+
+  for (const field of schemaFields) {
+    const value = pickFieldValue(field, frontmatter, rawFields);
+    if (value !== undefined) {
+      candidate[field] = value;
+    }
+  }
+
+  return candidate;
+}
+
 /**
  * Try to satisfy `outputSchema` from frontmatter fields alone.
  *
@@ -32,16 +158,22 @@ export async function tryFrontmatterFastPath(
 
   const validationErrors = validateFrontmatter(frontmatter);
   if (validationErrors.length > 0) {
+    log(
+      "9GNPS4WY",
+      `frontmatter validation errors: ${validationErrors.map((e) => e.message).join("; ")}`,
+    );
     return null;
   }
 
-  const candidate: Record<string, unknown> = {
+  const schema = getSchema(store, outputSchema);
-    status: frontmatter.status,
+  if (schema === null) {
-    next: frontmatter.next,
+    log("8FHMR2QX", `output schema not found in CAS: ${outputSchema}`);
-    confidence: frontmatter.confidence,
+    return null;
-    artifacts: [...frontmatter.artifacts],
+  }
-    scope: frontmatter.scope,
+
-  };
+  const schemaFields = extractSchemaFields(schema);
+  const rawFields = parseRawFrontmatterFields(raw);
+  const candidate = buildCandidate(frontmatter, rawFields, schemaFields);
 
   let outputHash: CasRef;
   let node: ReturnType<Store["get"]>;
@@ -50,10 +182,12 @@ export async function tryFrontmatterFastPath(
     outputHash = await store.put(outputSchema, candidate);
     node = store.get(outputHash);
   } catch {
+    log("2KMQT7NR", "failed to store frontmatter candidate in CAS");
     return null;
   }
 
   if (node === null || !validate(store, node)) {
+    log("2KMQT7NR", "stored frontmatter candidate failed schema validation");
     return null;
   }