Organon Tools Developer Skill

A Claude skill for agents developing organon-tools — ensures the tools that enforce methodology are built using methodology.

When to Use This Skill

Use this skill when:

• •Adding a new CLI command (organon <command>)
• •Adding a new verification gate
• •Adding a new MCP tool/prompt/resource
• •Evolving the methodology specification (book-llms/)
• •Fixing bugs or refactoring organon-tools code

Purpose: Ensure organon-tools development follows its own ETHOS.md constraints and PHILOSOPHY.md design decisions.

Identity Check (Always Start Here)

Before any work, load and internalize:

1. •Read organon/domains/tools/ETHOS.md - 6 invariants, 5 principles, 8 heuristics
2. •Read organon/domains/tools/PHILOSOPHY.md - 5 design decisions and trade-offs
3. •Read book-llms/three-layer-architecture.md - If working on verification gates

Critical constraint: This tool builds tools that enforce methodology. The builder must follow what it builds.

The 6 Invariants (Never Violate)

From organon/domains/tools/ETHOS.md:

1. •Schema fidelity - Frontmatter parser matches book-llms/frontmatter-system.md exactly
2. •Every command has tests - No untested code ships
3. •Gates fail builds, not warn - Verification gates produce pass/fail, never soft warnings
4. •Machine-parsable output - All commands support --format json
5. •Idempotent operations - Same input = same output, no side effects
6. •Breaking changes require major version bump - CLI, JSON schema, frontmatter schema

If your change violates any invariant, STOP and redesign.

The 5 Design Principles (Prioritized)

From organon/domains/tools/ETHOS.md:

1. •Schema fidelity over convenience - When book-llms/ spec conflicts with ease-of-use, spec wins
2. •Fail-fast over forgiving - Invalid input blocks execution, errors surface immediately
3. •Composability over monoliths - Commands work in Unix pipelines
4. •Testability over implementation speed - Pure functions with tests, thin CLI wrappers
5. •Clarity over brevity - Error messages explain what failed and how to fix it

Core Architecture Pattern

From organon/domains/tools/PHILOSOPHY.md:

src/
├── core/                   ← Pure functions (no I/O, no console, no process.exit)
│   ├── types.ts            ← FileSystem interface, result types
│   ├── <feature>.ts        ← Pure logic with tests
│   └── <feature>.test.ts   ← Vitest tests (>90% coverage)
├── cli/commands/           ← Thin wrappers (yargs handlers)
│   └── <command>.ts        ← Parse args → call core → format output
└── mcp/                    ← Thin MCP adapters
    ├── tools.ts            ← Wrap core functions as MCP tools
    └── prompts.ts          ← Methodology workflow templates

Pattern: Core logic is pure and testable. CLI and MCP are thin adapters.

Workflow 1: Adding a New CLI Command

Example: Adding organon check-links command

1. •

   Design phase (before coding):

   • • What does it do? (one sentence)
   • • Is it idempotent? (same input = same output?)
   • • Does it support --format json?
   • • What exit codes? (0 = success, 1 = failure)
   • • Does it compose with other commands?
2. •

   Implementation phase:

   bash

   # Create core utility (pure function)
   touch src/core/check-links.ts
   touch src/core/check-links.test.ts
   
   # Create CLI command wrapper
   touch src/cli/commands/check-links.ts
   

3. •

   Core utility structure (src/core/check-links.ts):

   typescript

   import { FileSystem, Result } from './types';
   
   export interface CheckLinksOptions {
     projectRoot: string;
     // ... other options
   }
   
   export interface CheckLinksResult {
     success: boolean;
     brokenLinks: Array<{ file: string; link: string; reason: string }>;
   }
   
   export async function checkLinks(
     options: CheckLinksOptions,
     fs: FileSystem
   ): Promise<CheckLinksResult> {
     // Pure logic here - no console.log, no process.exit
     // Return structured results
   }
   

4. •

   Write tests first (src/core/check-links.test.ts):

   typescript

   import { describe, it, expect } from 'vitest';
   import { checkLinks } from './check-links';
   import { MockFileSystem } from './test-utils';
   
   describe('checkLinks', () => {
     it('detects broken links', async () => {
       const fs = new MockFileSystem({ ... });
       const result = await checkLinks({ projectRoot: '.' }, fs);
       expect(result.brokenLinks).toHaveLength(1);
     });
   
     // ... more tests
   });
   

5. •

   CLI wrapper (src/cli/commands/check-links.ts):

   typescript

   import yargs from 'yargs';
   import { checkLinks } from '../../core/check-links';
   import { NodeFileSystem } from '../../core/node-fs';
   
   export const checkLinksCommand: yargs.CommandModule = {
     command: 'check-links',
     describe: 'Check for broken links in organon files',
     builder: (yargs) => {
       return yargs
         .option('format', {
           choices: ['human', 'json'] as const,
           default: 'human' as const,
         });
     },
     handler: async (args) => {
       const fs = new NodeFileSystem();
       const result = await checkLinks({ projectRoot: process.cwd() }, fs);
   
       if (args.format === 'json') {
         console.log(JSON.stringify(result, null, 2));
       } else {
         // Human-readable output
         if (result.brokenLinks.length === 0) {
           console.log('✓ No broken links found');
         } else {
           console.error('✗ Found broken links:');
           result.brokenLinks.forEach(l => {
             console.error(`  ${l.file}: ${l.link} (${l.reason})`);
           });
         }
       }
   
       process.exit(result.success ? 0 : 1);
     },
   };
   

6. •

   Register command (in src/cli/index.ts):

   typescript

   import { checkLinksCommand } from './commands/check-links';
   
   yargs
     .command(checkLinksCommand)
     // ... other commands
   

7. •

   Verification checklist:

   • • Core function is pure (no I/O, no console, no process.exit)
   • • Tests exist and pass (npm test)
   • • Coverage >90% for core logic
   • • Command supports --format json
   • • Command is idempotent
   • • Help text exists (organon check-links --help)
   • • Error messages are clear and actionable
   • • README.md updated with example usage
   • • No TypeScript compilation errors (npm run build)

Workflow 2: Adding a New Verification Gate

Example: Adding a "freshness" gate that checks last-modified dates

1. •

   Update specification first:

   • • Add gate description to book-llms/three-layer-architecture.md
   • • Define what it checks, when it fails, how to fix
   • • Commit spec changes before implementation
2. •

   Implementation (follow Workflow 1 pattern):

   bash

   # Core logic
   touch src/core/verify-freshness.ts
   touch src/core/verify-freshness.test.ts
   

3. •

   Gate structure (src/core/verify-freshness.ts):

   typescript

   import { FileSystem, VerificationResult } from './types';
   
   export async function verifyFreshness(
     projectRoot: string,
     fs: FileSystem
   ): Promise<VerificationResult> {
     return {
       gate: 'freshness',
       passed: boolean,
       errors: Array<{ file: string; message: string; fix: string }>,
       warnings: [], // Gates never warn, only fail
     };
   }
   

4. •

   Register gate (in src/core/verify.ts):

   typescript

   import { verifyFreshness } from './verify-freshness';
   
   const GATES = {
     'freshness': verifyFreshness,
     // ... other gates
   };
   

5. •

   Test coverage requirements:

   • • 100% coverage for verification gate logic (stricter than general 90% requirement)
   • • Test pass cases
   • • Test all failure modes
   • • Test fix suggestions are actionable
6. •

   Update CLI (src/cli/commands/verify.ts):

   typescript

   .option('gate', {
     type: 'array',
     choices: ['frontmatter', 'references', 'triplets', 'coverage', 'freshness'],
     description: 'Run specific gates (defaults to all)',
   })
   

7. •

   Verification checklist:

   • • Spec updated in book-llms/three-layer-architecture.md FIRST
   • • Gate fails builds (exit 1), never warns
   • • 100% test coverage for gate logic
   • • Error messages include file path, line number, and fix suggestion
   • • Gate registered in verify.ts
   • • CLI updated with new gate option
   • • README.md documents the new gate
   • • organon verify --gate freshness works

Workflow 3: Adding a New MCP Tool/Prompt

Example: Adding organon_check_dependencies MCP tool

1. •

   Core function exists (or create it following Workflow 1)

2. •

   Add MCP tool (src/mcp/tools.ts):

   typescript

   {
     name: 'organon_check_dependencies',
     description: 'Check if organon file dependencies are satisfied',
     inputSchema: {
       type: 'object',
       properties: {
         file: { type: 'string', description: 'Path to organon file' },
       },
       required: ['file'],
     },
     handler: async (args) => {
       const result = await checkDependencies(args.file, fs);
       return {
         content: [{ type: 'text', text: JSON.stringify(result, null, 2) }],
       };
     },
   }
   

3. •

   Add MCP prompt (src/mcp/prompts.ts) - If it's a workflow:

   typescript

   {
     name: 'check-organon-dependencies',
     description: 'Workflow for verifying organon dependency chains',
     arguments: [
       { name: 'scope', description: 'Scope to check (product, domain, feature)', required: false },
     ],
     handler: async (args) => {
       return {
         messages: [
           {
             role: 'user',
             content: {
               type: 'text',
               text: `# Check Organon Dependencies Workflow\n\n...`,
             },
           },
         ],
       };
     },
   }
   

4. •

   Verification checklist:

   • • Tool wraps existing core function (don't duplicate logic)
   • • Input schema is clear and validates properly
   • • Output is structured JSON
   • • Tool registered in src/mcp/server.ts
   • • MCP-SETUP.md updated with usage example
   • • Test with organon mcp and verify tool appears

Workflow 4: Evolving the Methodology (RFC-Aware)

Example: Adding a new frontmatter field

DANGER ZONE: Changes to book-llms/ affect ALL projects using Organon.

1. •

   RFC pattern (from book-llms/patterns.md):

   • • Create book-llms/rfcs/RFC-NNN-<title>.md
   • • Document: Problem, Proposal, Trade-offs, Migration path
   • • Get consensus (in this project: ensure it aligns with ETHOS.md)
   • • Update spec (book-llms/frontmatter-system.md)
   • • Update implementation (packages/tools/src/core/frontmatter-parser.ts)
   • • Update tests
   • • Document migration in CHANGELOG.md
   • • Bump version (breaking = major, additive = minor)
2. •

   Breaking change checklist (requires major version bump):

   • • Does it change frontmatter schema? (breaking)
   • • Does it change CLI interface? (breaking)
   • • Does it change JSON output schema? (breaking)
   • • Does it remove/rename a command? (breaking)
   • • If any YES, bump major version
3. •

   Invariant check:

   • •Schema fidelity: Implementation must match spec exactly
   • •Breaking changes require major version bump: Semver enforced

Common Pitfalls (Don't Do This)

1. •❌ Adding logic to CLI commands → ✅ Add to src/core/, CLI is thin wrapper
2. •❌ Using console.log in core functions → ✅ Return structured results, CLI formats
3. •❌ Using process.exit in core functions → ✅ Return success/failure, CLI exits
4. •❌ Writing tests after code → ✅ Write tests first (TDD pattern)
5. •❌ Making gates warn instead of fail → ✅ Gates fail builds (INV-TOOLS-3)
6. •❌ Skipping --format json support → ✅ All commands must support it (INV-TOOLS-4)
7. •❌ Implementing before spec updated → ✅ Update book-llms/ spec first
8. •❌ Auto-fixing invalid frontmatter → ✅ Fail-fast, force user to fix (principle #2)

Pre-Commit Verification

Before committing ANY code:

# 1. Tests pass
npm test

# 2. No TypeScript errors
npm run build

# 3. Self-verification (dogfooding)
npm run organon verify

# 4. Coverage check (>90% for core, 100% for gates)
npm run test:coverage

If any fail, do not commit.

When in Doubt

1. •Check ETHOS.md - Does this violate an invariant?
2. •Check PHILOSOPHY.md - Does this align with design decisions?
3. •Check three-layer-architecture.md - Is this the right pattern for gates?
4. •Ask: Would this tool enforce what I'm about to build?

Remember: Organon-tools builds tools that enforce methodology. If you wouldn't want the tool to allow this pattern, don't implement it.

Meta-Principle

The tools that enforce constraints must be built with more discipline than the code they govern.

If organon-tools has untested code, how can it enforce test coverage on others? If organon-tools has invalid frontmatter, how can it validate others? If organon-tools violates its own ETHOS.md, the methodology loses credibility.

Build the tools you wish existed when auditing someone else's work.

Error Recovery