feat: add developer skill — coding conventions + architecture guide

Adds 'uwf skill developer' for contributors to the workflow engine.
Covers: monorepo structure, dependency layers, functional-first conventions,
error handling, logging with tagged logger, development workflow,
testing, publishing, key modules (moderator, extract pipeline, createAgent).

Refs #541

packages/cli-workflow/src/__tests__/skill.test.ts

@@ -10,6 +10,7 @@ import {
   cmdSkillArchitecture,
   cmdSkillAuthor,
   cmdSkillCli,
+  cmdSkillDeveloper,
   cmdSkillList,
   cmdSkillModerator,
   cmdSkillUser,
@@ -27,6 +28,7 @@ describe("skill commands", () => {
     expect(result).toContain("actor");
     expect(result).toContain("user");
     expect(result).toContain("author");
+    expect(result).toContain("developer");
     for (const name of result) {
       expect(name).toMatch(/^\S+$/);
     }
@@ -97,6 +99,15 @@ describe("skill commands", () => {
     expect(result.length).toBeGreaterThan(500);
   });
 
+  test("skill developer returns non-empty markdown string", () => {
+    const result = cmdSkillDeveloper();
+    expect(typeof result).toBe("string");
+    expect(result).toContain("Monorepo");
+    expect(result).toContain("CAS");
+    expect(result).toContain("Biome");
+    expect(result.length).toBeGreaterThan(500);
+  });
+
   test("skill help subcommand is suppressed", () => {
     const output = execFileSync("bun", ["src/cli.ts", "skill", "--help"], {
       cwd: join(__dirname, "..", ".."),
@@ -111,6 +122,7 @@ describe("skill commands", () => {
     expect(output).toContain("actor");
     expect(output).toContain("user");
     expect(output).toContain("author");
+    expect(output).toContain("developer");
     expect(output).toContain("list");
   });
 });

packages/cli-workflow/src/cli.ts

@@ -21,6 +21,7 @@ import {
   cmdSkillArchitecture,
   cmdSkillAuthor,
   cmdSkillCli,
+  cmdSkillDeveloper,
   cmdSkillList,
   cmdSkillModerator,
   cmdSkillUser,
@@ -520,6 +521,13 @@ skill
     console.log(cmdSkillAuthor());
   });
 
+skill
+  .command("developer")
+  .description("Print the developer reference (coding conventions + architecture)")
+  .action(() => {
+    console.log(cmdSkillDeveloper());
+  });
+
 skill
   .command("moderator")
   .description("Print the moderator reference")

packages/cli-workflow/src/commands/skill.ts

@@ -3,6 +3,7 @@ export {
   generateArchitectureReference as cmdSkillArchitecture,
   generateAuthorReference as cmdSkillAuthor,
   generateCliReference as cmdSkillCli,
+  generateDeveloperReference as cmdSkillDeveloper,
   generateModeratorReference as cmdSkillModerator,
   generateUserReference as cmdSkillUser,
   generateYamlReference as cmdSkillYaml,
@@ -16,6 +17,7 @@ const SKILL_NAMES = [
   "actor",
   "user",
   "author",
+  "developer",
 ] as const;
 
 export function cmdSkillList(): ReadonlyArray<string> {

packages/workflow-util/src/developer-reference.ts

@@ -0,0 +1,140 @@
+export function generateDeveloperReference(): string {
+  return `# Developer Reference
+
+Guide for contributing to the workflow engine codebase.
+
+## Monorepo Structure
+
+\`\`\`
+packages/
+  workflow-protocol/      # Shared types (WorkflowPayload, StepNodePayload, etc.)
+  workflow-util/          # Base32, ULID, logger, frontmatter parsing, skill references
+  workflow-util-agent/    # createAgent factory, context builder, extract pipeline
+  workflow-agent-hermes/  # uwf-hermes CLI (spawns Hermes chat sessions)
+  workflow-agent-builtin/ # uwf-builtin CLI (direct LLM calls via OpenAI API)
+  cli-workflow/           # uwf CLI (moderator, thread/step/cas/config commands)
+\`\`\`
+
+Dependency layers (each only imports from packages above it):
+\`\`\`
+protocol → util → util-agent → agent-hermes / agent-builtin / cli-workflow
+\`\`\`
+
+External CAS: \`@uncaged/json-cas\` (store API, hashing, schema validation) + \`@uncaged/json-cas-fs\` (filesystem backend).
+
+## Coding Conventions
+
+### Functional-first
+
+| Rule | Description |
+|------|-------------|
+| \`type\` over \`interface\` | All type definitions use \`type\` |
+| \`function\` over \`class\` | Pure functions + closures, no class |
+| No \`this\` | Functions must not depend on \`this\` context |
+| No inheritance | No \`extends\`, \`implements\`, \`abstract\` |
+| No optional properties | Use \`T \\| null\` instead of \`?:\` |
+| Immutability first | Use \`Readonly<T>\`, \`as const\`, avoid mutation |
+
+Classes allowed only when required by third-party libraries or for Error subclasses.
+
+### Error Handling
+
+- \`Result<T, E>\` type for expected failures (\`ok\`/\`err\` constructors from \`@uncaged/workflow-util\`)
+- \`throw\` only for unrecoverable bugs
+- No try-catch for flow control
+
+### Async
+
+Always \`async/await\`, never \`.then()\` chains.
+
+### Logging
+
+\`console.*\` is banned (Biome \`noConsole\` rule). Use the structured logger:
+
+\`\`\`typescript
+import { createLogger } from "@uncaged/workflow-util";
+const log = createLogger();
+log("4KNMR2PX", "Loading workflow...");  // 8-char Crockford Base32 tag
+\`\`\`
+
+Each call site gets a unique hand-written tag. \`grep "4KNMR2PX"\` in logs → instant code location.
+
+CLI package (\`@uncaged/cli-workflow\`) may use \`console.log\` for user-facing output with a biome-ignore comment.
+
+### No Dynamic Import
+
+No \`await import()\` in production code. Always static top-level \`import\`. Test files are exempt.
+
+### Naming
+
+- Workflow names: verb-first kebab-case (\`solve-issue\`, \`review-code\`)
+- IDs: Crockford Base32 — CAS hash (XXH64, 13-char), Thread ID (ULID, 26-char)
+
+## Development Workflow
+
+\`\`\`bash
+bun install                 # install all workspace deps
+bun run build               # tsc --build (all packages)
+bun run check               # tsc + biome check + lint-log-tags
+bun run format              # biome format --write
+bun test                    # run all tests
+\`\`\`
+
+Before committing: \`bun run check\` + \`bun test\` must both pass.
+
+### Testing
+
+- \`cli-workflow\`: vitest
+- Other packages: \`bun test\`
+- Test files live in \`__tests__/\` directories
+
+### Publishing
+
+Fixed-mode versioning — all \`@uncaged/*\` packages share the same version number.
+
+\`\`\`bash
+bun changeset               # describe the change
+bun version                 # bump versions + changelogs
+bun release                 # build + test + publish to npmjs
+\`\`\`
+
+## Key Modules
+
+### Moderator (\`cli-workflow/src/moderator/\`)
+
+Status-based graph evaluator. Reads \`graph[lastRole][output.$status]\` to determine the next role. Zero LLM cost.
+
+### Extract Pipeline (\`workflow-util-agent/src/\`)
+
+1. Agent produces frontmatter markdown
+2. \`parseFrontmatterMarkdown()\` extracts YAML frontmatter
+3. \`tryFrontmatterFastPath()\` validates against role's output schema
+4. If fast path fails, retries up to 2 times via agent continue
+5. Validated output stored as CAS node
+
+### createAgent Factory (\`workflow-util-agent/src/run.ts\`)
+
+Shared entry point for all agent CLIs. Handles:
+- Argument parsing (\`--thread\`, \`--role\`, \`--prompt\`)
+- Context building (thread history, workflow definition)
+- Output extraction and CAS persistence
+- Frontmatter retry loop
+
+### CAS Integration
+
+All data is CAS-addressed via \`@uncaged/json-cas\`:
+- \`store.put(schemaHash, data)\` → content hash
+- \`store.get(hash)\` → node
+- \`validate(store, node)\` → schema check
+- Schemas registered at workflow add time
+
+## Commit Convention
+
+\`\`\`
+<type>(<scope>): <description>
+
+type: feat | fix | refactor | docs | chore | test
+scope: workflow | cli | moderator | agent-kit | hermes | util | protocol
+\`\`\`
+`;
+}

packages/workflow-util/src/index.ts

@@ -3,6 +3,7 @@ export { generateArchitectureReference } from "./architecture-reference.js";
 export { generateAuthorReference } from "./author-reference.js";
 export { encodeUint64AsCrockford } from "./base32.js";
 export { generateCliReference } from "./cli-reference.js";
+export { generateDeveloperReference } from "./developer-reference.js";
 export { env } from "./env.js";
 export type {
   AgentFrontmatter,