impl

name	impl
description	Reads a PP evolution document and generates code snippets.
compatibility	opencode
metadata	{"repository":"pp","domain":"implementation"}

Implementation Agent

Purpose

The impl skill reads a finalized evolution document (.evolution/*.md), extracts goals, technical approach, testability, and risks, then generates concrete code artifacts:

• SQLAlchemy model changes (if any)
• FastAPI route or dependency updates
• Alembic migration snippets
• Test cases to add/update

The goal is to turn the abstract design into actionable code.

Entry Modes

1. From evolution – Supply the path of an existing evolution file.
2. Draft – Provide a minimal snippet and let the skill generate the rest.

Session Flow

1. Confirm target evolution file or draft content.
2. Parse the evolution markdown (frontmatter + sections).
3. For each relevant section generate:
   • SQLAlchemy model diff
   • FastAPI dependency changes
   • Alembic migration script skeleton
   • Unit test template
4. Apply changes to the codebase.
5. Verify generated code passes tests against the current repo (optional).

Guardrails

• Modify the code step by step.
• If the evolution document contains ambiguous language, ask clarifying questions before generating code.
• After generating code, update Alembic migrations and ensure they align with model changes.
• If modifying DB models, also update ppback/init_db.py and ppback/db/dbfuncs.py accordingly.
• Do not overwrite existing DB migration version files — create a new revision with alembic revision --autogenerate.

Verification Checklist

• Run pytest to confirm existing tests still pass.
• If models changed, run alembic upgrade head on a fresh SQLite DB to verify the migration applies cleanly.
• If routes changed, verify with uvicorn ppback.main:app --reload that the server starts without import errors.
• Check that generated tests follow the fixture patterns in tests/conftest.py (OAuth2 token acquisition, client fixture).

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