commit 985d8fce764dae479e7b77b632429abe38891ee8 Author: Matt Pocock Date: Tue Feb 3 11:15:48 2026 +0000 Initial commit diff --git a/edit-article/SKILL.md b/edit-article/SKILL.md new file mode 100644 index 0000000..0e76ce8 --- /dev/null +++ b/edit-article/SKILL.md @@ -0,0 +1,14 @@ +--- +name: edit-article +description: The user will invoke this skill to help them edit an article. +--- + +1. First, divide the article into sections based on its headings. Think about the main points you want to make during those sections. + +Consider that information is a directed acyclic graph, and that pieces of information can depend on other pieces of information. Make sure that the order of the sections and their contents respects these dependencies. + +Confirm the sections with the user. + +2. For each section: + +2a. Rewrite the section to improve clarity, coherence, and flow. Use maximum 240 characters per paragraph. diff --git a/request-refactor-plan/SKILL.md b/request-refactor-plan/SKILL.md new file mode 100644 index 0000000..382eb5a --- /dev/null +++ b/request-refactor-plan/SKILL.md @@ -0,0 +1,68 @@ +--- +name: request-refactor-plan +description: Use this skill when user wants to create a refactor plan. +--- + +This skill will be invoked when the user wants to create a refactor request. You should go through the steps below. You may skip steps if you don't consider them necessary. + +1. Ask the user for a long, detailed description of the problem they want to solve and any potential ideas for solutions. + +2. Explore the repo to verify their assertions and understand the current state of the codebase. + +3. Ask whether they have considered other options, and present other options to them. + +4. Interview the user about the implementation. Be extremely detailed and thorough. + +5. Hammer out the exact scope of the implementation. Work out what you plan to change and what you plan not to change. + +6. Look in the codebase to check for test coverage of this area of the codebase. If there is insufficient test coverage, ask the user what their plans for testing are. + +7. Break the implementation into a plan of tiny commits. Remember Martin Fowler's advice to "make each refactoring step as small as possible, so that you can always see the program working." + +8. Create a GitHub issue with the refactor plan. Use the following template for the issue description: + + + +## Problem Statement + +The problem that the developer is facing, from the developer's perspective. + +## Solution + +The solution to the problem, from the developer's perspective. + +## Commits + +A LONG, detailed implementation plan. Write the plan in plain English, breaking down the implementation into the tiniest commits possible. Each commit should leave the codebase in a working state. + +## Decision Document + +A list of implementation decisions that were made. This can include: + +- The modules that will be built/modified +- The interfaces of those modules that will be modified +- Technical clarifications from the developer +- Architectural decisions +- Schema changes +- API contracts +- Specific interactions + +Do NOT include specific file paths or code snippets. They may end up being outdated very quickly. + +## Testing Decisions + +A list of testing decisions that were made. Include: + +- A description of what makes a good test (only test external behavior, not implementation details) +- Which modules will be tested +- Prior art for the tests (i.e. similar types of tests in the codebase) + +## Out of Scope + +A description of the things that are out of scope for this refactor. + +## Further Notes (optional) + +Any further notes about the refactor. + + diff --git a/tdd/SKILL.md b/tdd/SKILL.md new file mode 100644 index 0000000..5280417 --- /dev/null +++ b/tdd/SKILL.md @@ -0,0 +1,82 @@ +--- +name: tdd +description: Test-driven development with red-green-refactor loop. Use when user wants to build features or fix bugs using TDD, mentions "red-green-refactor", wants integration tests, or asks for test-first development. +--- + +# Test-Driven Development + +## Philosophy + +**Core principle**: Tests should verify behavior through public interfaces, not implementation details. Code can change entirely; tests shouldn't. + +**Good tests** are integration-style: they exercise real code paths through public APIs. They describe _what_ the system does, not _how_ it does it. A good test reads like a specification - "user can checkout with valid cart" tells you exactly what capability exists. These tests survive refactors because they don't care about internal structure. + +**Bad tests** are coupled to implementation. They mock internal collaborators, test private methods, or verify through external means (like querying a database directly instead of using the interface). The warning sign: your test breaks when you refactor, but behavior hasn't changed. If you rename an internal function and tests fail, those tests were testing implementation, not behavior. + +See [tests.md](tests.md) for examples and [mocking.md](mocking.md) for mocking guidelines. + +## Workflow + +### 1. Planning + +Before writing any code: + +- [ ] Confirm with user what interface changes are needed +- [ ] Confirm with user which behaviors to test (prioritize) +- [ ] Identify opportunities for [deep modules](deep-modules.md) (small interface, deep implementation) +- [ ] Design interfaces for [testability](interface-design.md) +- [ ] List the behaviors to test (not implementation steps) +- [ ] Get user approval on the plan + +Ask: "What should the public interface look like? Which behaviors are most important to test?" + +**You can't test everything.** Confirm with the user exactly which behaviors matter most. Focus testing effort on critical paths and complex logic, not every possible edge case. + +### 2. Tracer Bullet + +Write ONE test that confirms ONE thing about the system: + +``` +RED: Write test for first behavior → test fails +GREEN: Write minimal code to pass → test passes +``` + +This is your tracer bullet - proves the path works end-to-end. + +### 3. Incremental Loop + +For each remaining behavior: + +``` +RED: Write next test → fails +GREEN: Minimal code to pass → passes +``` + +Rules: + +- One test at a time +- Only enough code to pass current test +- Don't anticipate future tests +- Keep tests focused on observable behavior + +### 4. Refactor + +After all tests pass, look for [refactor candidates](refactoring.md): + +- [ ] Extract duplication +- [ ] Deepen modules (move complexity behind simple interfaces) +- [ ] Apply SOLID principles where natural +- [ ] Consider what new code reveals about existing code +- [ ] Run tests after each refactor step + +**Never refactor while RED.** Get to GREEN first. + +## Checklist Per Cycle + +``` +[ ] Test describes behavior, not implementation +[ ] Test uses public interface only +[ ] Test would survive internal refactor +[ ] Code is minimal for this test +[ ] No speculative features added +``` diff --git a/tdd/deep-modules.md b/tdd/deep-modules.md new file mode 100644 index 0000000..0d9720c --- /dev/null +++ b/tdd/deep-modules.md @@ -0,0 +1,33 @@ +# Deep Modules + +From "A Philosophy of Software Design": + +**Deep module** = small interface + lots of implementation + +``` +┌─────────────────────┐ +│ Small Interface │ ← Few methods, simple params +├─────────────────────┤ +│ │ +│ │ +│ Deep Implementation│ ← Complex logic hidden +│ │ +│ │ +└─────────────────────┘ +``` + +**Shallow module** = large interface + little implementation (avoid) + +``` +┌─────────────────────────────────┐ +│ Large Interface │ ← Many methods, complex params +├─────────────────────────────────┤ +│ Thin Implementation │ ← Just passes through +└─────────────────────────────────┘ +``` + +When designing interfaces, ask: + +- Can I reduce the number of methods? +- Can I simplify the parameters? +- Can I hide more complexity inside? diff --git a/tdd/interface-design.md b/tdd/interface-design.md new file mode 100644 index 0000000..a0a20ca --- /dev/null +++ b/tdd/interface-design.md @@ -0,0 +1,31 @@ +# Interface Design for Testability + +Good interfaces make testing natural: + +1. **Accept dependencies, don't create them** + + ```typescript + // Testable + function processOrder(order, paymentGateway) {} + + // Hard to test + function processOrder(order) { + const gateway = new StripeGateway(); + } + ``` + +2. **Return results, don't produce side effects** + + ```typescript + // Testable + function calculateDiscount(cart): Discount {} + + // Hard to test + function applyDiscount(cart): void { + cart.total -= discount; + } + ``` + +3. **Small surface area** + - Fewer methods = fewer tests needed + - Fewer params = simpler test setup diff --git a/tdd/mocking.md b/tdd/mocking.md new file mode 100644 index 0000000..71cbfee --- /dev/null +++ b/tdd/mocking.md @@ -0,0 +1,59 @@ +# When to Mock + +Mock at **system boundaries** only: + +- External APIs (payment, email, etc.) +- Databases (sometimes - prefer test DB) +- Time/randomness +- File system (sometimes) + +Don't mock: + +- Your own classes/modules +- Internal collaborators +- Anything you control + +## Designing for Mockability + +At system boundaries, design interfaces that are easy to mock: + +**1. Use dependency injection** + +Pass external dependencies in rather than creating them internally: + +```typescript +// Easy to mock +function processPayment(order, paymentClient) { + return paymentClient.charge(order.total); +} + +// Hard to mock +function processPayment(order) { + const client = new StripeClient(process.env.STRIPE_KEY); + return client.charge(order.total); +} +``` + +**2. Prefer SDK-style interfaces over generic fetchers** + +Create specific functions for each external operation instead of one generic function with conditional logic: + +```typescript +// GOOD: Each function is independently mockable +const api = { + getUser: (id) => fetch(`/users/${id}`), + getOrders: (userId) => fetch(`/users/${userId}/orders`), + createOrder: (data) => fetch('/orders', { method: 'POST', body: data }), +}; + +// BAD: Mocking requires conditional logic inside the mock +const api = { + fetch: (endpoint, options) => fetch(endpoint, options), +}; +``` + +The SDK approach means: +- Each mock returns one specific shape +- No conditional logic in test setup +- Easier to see which endpoints a test exercises +- Type safety per endpoint diff --git a/tdd/refactoring.md b/tdd/refactoring.md new file mode 100644 index 0000000..8a44439 --- /dev/null +++ b/tdd/refactoring.md @@ -0,0 +1,10 @@ +# Refactor Candidates + +After TDD cycle, look for: + +- **Duplication** → Extract function/class +- **Long methods** → Break into private helpers (keep tests on public interface) +- **Shallow modules** → Combine or deepen +- **Feature envy** → Move logic to where data lives +- **Primitive obsession** → Introduce value objects +- **Existing code** the new code reveals as problematic diff --git a/tdd/tests.md b/tdd/tests.md new file mode 100644 index 0000000..ff22f80 --- /dev/null +++ b/tdd/tests.md @@ -0,0 +1,61 @@ +# Good and Bad Tests + +## Good Tests + +**Integration-style**: Test through real interfaces, not mocks of internal parts. + +```typescript +// GOOD: Tests observable behavior +test("user can checkout with valid cart", async () => { + const cart = createCart(); + cart.add(product); + const result = await checkout(cart, paymentMethod); + expect(result.status).toBe("confirmed"); +}); +``` + +Characteristics: + +- Tests behavior users/callers care about +- Uses public API only +- Survives internal refactors +- Describes WHAT, not HOW +- One logical assertion per test + +## Bad Tests + +**Implementation-detail tests**: Coupled to internal structure. + +```typescript +// BAD: Tests implementation details +test("checkout calls paymentService.process", async () => { + const mockPayment = jest.mock(paymentService); + await checkout(cart, payment); + expect(mockPayment.process).toHaveBeenCalledWith(cart.total); +}); +``` + +Red flags: + +- Mocking internal collaborators +- Testing private methods +- Asserting on call counts/order +- Test breaks when refactoring without behavior change +- Test name describes HOW not WHAT +- Verifying through external means instead of interface + +```typescript +// BAD: Bypasses interface to verify +test("createUser saves to database", async () => { + await createUser({ name: "Alice" }); + const row = await db.query("SELECT * FROM users WHERE name = ?", ["Alice"]); + expect(row).toBeDefined(); +}); + +// GOOD: Verifies through interface +test("createUser makes user retrievable", async () => { + const user = await createUser({ name: "Alice" }); + const retrieved = await getUser(user.id); + expect(retrieved.name).toBe("Alice"); +}); +``` diff --git a/write-a-prd/SKILL.md b/write-a-prd/SKILL.md new file mode 100644 index 0000000..211f0ec --- /dev/null +++ b/write-a-prd/SKILL.md @@ -0,0 +1,78 @@ +--- +name: write-a-prd +description: Use this skill when writing a PRD for a feature. +--- + +This skill will be invoked when the user wants to create a PRD. You should go through the steps below. You may skip steps if you don't consider them necessary. + +1. Ask the user for a long, detailed description of the problem they want to solve and any potential ideas for solutions. + +2. Explore the repo to verify their assertions and understand the current state of the codebase. + +3. Ask whether they have considered other options, and present other options to them. + +4. Interview the user about the implementation. Be extremely detailed and thorough. + +5. Hammer out the exact scope of the implementation. Work out what you plan to build and what you DON'T plan to build as part of this PRD. + +6. Sketch out the major modules you will need to build or modify to complete the implementation. Actively look for opportunities to extract deep modules that can be tested in isolation. + +A deep module (as opposed to a shallow module) is one which encapsulates a lot of functionality in a simple, testable interface which rarely changes. + +Check with the user that these modules match their expectations. Check with the user which modules they want tests written for. + +7. Once you have a complete understanding of the problem and solution, use the template below to write the PRD. The PRD should be submitted as a GitHub issue. + + + +## Problem Statement + +The problem that the user is facing, from the user's perspective. + +## Solution + +The solution to the problem, from the user's perspective. + +## User Stories + +A LONG, numbered list of user stories. Each user story should be in the format of: + +1. As an , I want a , so that + + +1. As a mobile bank customer, I want to see balance on my accounts, so that I can make better informed decisions about my spending + + +This list of user stories should be extremely extensive and cover all aspects of the feature. + +## Implementation Decisions + +A list of implementation decisions that were made. This can include: + +- The modules that will be built/modified +- The interfaces of those modules that will be modified +- Technical clarifications from the developer +- Architectural decisions +- Schema changes +- API contracts +- Specific interactions + +Do NOT include specific file paths or code snippets. They may end up being outdated very quickly. + +## Testing Decisions + +A list of testing decisions that were made. Include: + +- A description of what makes a good test (only test external behavior, not implementation details) +- Which modules will be tested +- Prior art for the tests (i.e. similar types of tests in the codebase) + +## Out of Scope + +A description of the things that are out of scope for this PRD. + +## Further Notes + +Any further notes about the feature. + + diff --git a/write-a-skill/SKILL.md b/write-a-skill/SKILL.md new file mode 100644 index 0000000..7339c8a --- /dev/null +++ b/write-a-skill/SKILL.md @@ -0,0 +1,117 @@ +--- +name: write-a-skill +description: Create new agent skills with proper structure, progressive disclosure, and bundled resources. Use when user wants to create, write, or build a new skill. +--- + +# Writing Skills + +## Process + +1. **Gather requirements** - ask user about: + - What task/domain does the skill cover? + - What specific use cases should it handle? + - Does it need executable scripts or just instructions? + - Any reference materials to include? + +2. **Draft the skill** - create: + - SKILL.md with concise instructions + - Additional reference files if content exceeds 500 lines + - Utility scripts if deterministic operations needed + +3. **Review with user** - present draft and ask: + - Does this cover your use cases? + - Anything missing or unclear? + - Should any section be more/less detailed? + +## Skill Structure + +``` +skill-name/ +├── SKILL.md # Main instructions (required) +├── REFERENCE.md # Detailed docs (if needed) +├── EXAMPLES.md # Usage examples (if needed) +└── scripts/ # Utility scripts (if needed) + └── helper.js +``` + +## SKILL.md Template + +```md +--- +name: skill-name +description: Brief description of capability. Use when [specific triggers]. +--- + +# Skill Name + +## Quick start + +[Minimal working example] + +## Workflows + +[Step-by-step processes with checklists for complex tasks] + +## Advanced features + +[Link to separate files: See [REFERENCE.md](REFERENCE.md)] +``` + +## Description Requirements + +The description is **the only thing your agent sees** when deciding which skill to load. It's surfaced in the system prompt alongside all other installed skills. Your agent reads these descriptions and picks the relevant skill based on the user's request. + +**Goal**: Give your agent just enough info to know: + +1. What capability this skill provides +2. When/why to trigger it (specific keywords, contexts, file types) + +**Format**: + +- Max 1024 chars +- Write in third person +- First sentence: what it does +- Second sentence: "Use when [specific triggers]" + +**Good example**: + +``` +Extract text and tables from PDF files, fill forms, merge documents. Use when working with PDF files or when user mentions PDFs, forms, or document extraction. +``` + +**Bad example**: + +``` +Helps with documents. +``` + +The bad example gives your agent no way to distinguish this from other document skills. + +## When to Add Scripts + +Add utility scripts when: + +- Operation is deterministic (validation, formatting) +- Same code would be generated repeatedly +- Errors need explicit handling + +Scripts save tokens and improve reliability vs generated code. + +## When to Split Files + +Split into separate files when: + +- SKILL.md exceeds 100 lines +- Content has distinct domains (finance vs sales schemas) +- Advanced features are rarely needed + +## Review Checklist + +After drafting, verify: + +- [ ] Description includes triggers ("Use when...") +- [ ] SKILL.md under 100 lines +- [ ] No time-sensitive info +- [ ] Consistent terminology +- [ ] Concrete examples included +- [ ] References one level deep