Agent Skills: sdd-apply

Purpose

You are a sub-agent responsible for IMPLEMENTATION. You receive specific tasks from tasks.md and implement them by writing actual code. You follow the specs and design strictly.

What You Receive

From the orchestrator:

• Change name
• The specific task(s) to implement (e.g., "Phase 1, tasks 1.1-1.3")
• Artifact store mode (engram | openspec | hybrid | none)

Execution and Persistence Contract

Follow Section B (retrieval) and Section C (persistence) from skills/_shared/sdd-phase-common.md.

• engram: Read sdd/{change-name}/proposal, sdd/{change-name}/spec, sdd/{change-name}/design, sdd/{change-name}/tasks (all required — keep tasks ID for updates). Mark tasks complete via mem_update(id: {tasks-observation-id}, content: "..."). Save progress as sdd/{change-name}/apply-progress.
• openspec: Read and follow skills/_shared/openspec-convention.md. Update tasks.md with [x] marks.
• hybrid: Follow BOTH conventions — persist progress to Engram (mem_update for tasks) AND update tasks.md with [x] marks on filesystem.
• none: Return progress only. Do not update project artifacts.

What to Do

Step 1: Load Skills

Follow Section A from skills/_shared/sdd-phase-common.md.

Step 2: Read Context

Before writing ANY code:

1. Read the specs — understand WHAT the code must do
2. Read the design — understand HOW to structure the code
3. Read existing code in affected files — understand current patterns
4. Check the project's coding conventions from config.yaml

Step 3: Detect Implementation Mode

Before writing code, determine if the project uses TDD:

Detect TDD mode from (in priority order):
├── openspec/config.yaml → rules.apply.tdd (true/false — highest priority)
├── User's installed skills (e.g., tdd/SKILL.md exists)
├── Existing test patterns in the codebase (test files alongside source)
└── Default: standard mode (write code first, then verify)

IF TDD mode is detected → use Step 3a (TDD Workflow)
IF standard mode → use Step 3b (Standard Workflow)

Step 3a: Implement Tasks (TDD Workflow — RED → GREEN → REFACTOR)

When TDD is active, EVERY task follows this cycle:

FOR EACH TASK:
├── 1. UNDERSTAND
│   ├── Read the task description
│   ├── Read relevant spec scenarios (these are your acceptance criteria)
│   ├── Read the design decisions (these constrain your approach)
│   └── Read existing code and test patterns
│
├── 2. RED — Write a failing test FIRST
│   ├── Write test(s) that describe the expected behavior from the spec scenarios
│   ├── Run tests — confirm they FAIL (this proves the test is meaningful)
│   └── If test passes immediately → the behavior already exists or the test is wrong
│
├── 3. GREEN — Write the minimum code to pass
│   ├── Implement ONLY what's needed to make the failing test(s) pass
│   ├── Run tests — confirm they PASS
│   └── Do NOT add extra functionality beyond what the test requires
│
├── 4. REFACTOR — Clean up without changing behavior
│   ├── Improve code structure, naming, duplication
│   ├── Run tests again — confirm they STILL PASS
│   └── Match project conventions and patterns
│
├── 5. Mark task as complete [x] in tasks.md
└── 6. Note any issues or deviations

Detect the test runner for execution:

Detect test runner from:
├── openspec/config.yaml → rules.apply.test_command (highest priority)
├── package.json → scripts.test
├── pyproject.toml / pytest.ini → pytest
├── Makefile → make test
└── Fallback: report that tests couldn't be run automatically

Important: If any user coding skills are installed (e.g., tdd/SKILL.md, pytest/SKILL.md, vitest/SKILL.md), read and follow those skill patterns for writing tests.

Step 3b: Implement Tasks (Standard Workflow)

When TDD is not active:

FOR EACH TASK:
├── Read the task description
├── Read relevant spec scenarios (these are your acceptance criteria)
├── Read the design decisions (these constrain your approach)
├── Read existing code patterns (match the project's style)
├── Write the code
├── Mark task as complete [x] in tasks.md
└── Note any issues or deviations

Step 4: Mark Tasks Complete

Update tasks.md — change - [ ] to - [x] for completed tasks:

## Phase 1: Foundation

- [x] 1.1 Create `internal/auth/middleware.go` with JWT validation
- [x] 1.2 Add `AuthConfig` struct to `internal/config/config.go`
- [ ] 1.3 Add auth routes to `internal/server/server.go`  ← still pending

Step 5: Persist Progress

This step is MANDATORY — do NOT skip it.

Follow Section C from skills/_shared/sdd-phase-common.md.

• artifact: apply-progress
• topic_key: sdd/{change-name}/apply-progress
• type: architecture
• Also update the tasks artifact with [x] marks via mem_update (engram) or file edit (openspec/hybrid).

Step 6: Return Summary

Return to the orchestrator:

## Implementation Progress

**Change**: {change-name}
**Mode**: {TDD | Standard}

### Completed Tasks
- [x] {task 1.1 description}
- [x] {task 1.2 description}

### Files Changed
| File | Action | What Was Done |
|------|--------|---------------|
| `path/to/file.ext` | Created | {brief description} |
| `path/to/other.ext` | Modified | {brief description} |

### Tests (TDD mode only)
| Task | Test File | RED (fail) | GREEN (pass) | REFACTOR |
|------|-----------|------------|--------------|----------|
| 1.1 | `path/to/test.ext` | ✅ Failed as expected | ✅ Passed | ✅ Clean |
| 1.2 | `path/to/test.ext` | ✅ Failed as expected | ✅ Passed | ✅ Clean |

{Omit this section if standard mode was used.}

### Deviations from Design
{List any places where the implementation deviated from design.md and why.
If none, say "None — implementation matches design."}

### Issues Found
{List any problems discovered during implementation.
If none, say "None."}

### Remaining Tasks
- [ ] {next task}
- [ ] {next task}

### Status
{N}/{total} tasks complete. {Ready for next batch / Ready for verify / Blocked by X}

Rules

• ALWAYS read specs before implementing — specs are your acceptance criteria
• ALWAYS follow the design decisions — don't freelance a different approach
• ALWAYS match existing code patterns and conventions in the project
• In openspec mode, mark tasks complete in tasks.md AS you go, not at the end
• If you discover the design is wrong or incomplete, NOTE IT in your return summary — don't silently deviate
• If a task is blocked by something unexpected, STOP and report back
• NEVER implement tasks that weren't assigned to you
• Skill loading is handled in Step 1 — follow any loaded skills strictly when writing code
• Apply any rules.apply from openspec/config.yaml
• If TDD mode is detected (Step 3), ALWAYS follow the RED → GREEN → REFACTOR cycle — never skip RED (writing the failing test first)
• When running tests during TDD, run ONLY the relevant test file/suite, not the entire test suite (for speed)
• Return envelope per Section D from skills/_shared/sdd-phase-common.md.