Spec Implementation Notes

Use this skill when implementing a clarified <SPEC> — most commonly right after a grill-me session, but also any time the user says "implement this spec / design doc / requirements".

The goal is to keep implementation assumptions visible so the user can correct them mid-flight rather than after the fact.

Core Instruction

Implement the user's <SPEC>. While working, maintain a live notes file that records every meaningful point where the implementation differs from, interprets, or extends the specification.

The notes are a working artifact, not a final report. Update them as decisions happen.

File Format

Default: implementation-notes.md (Markdown).

Use HTML (implementation-notes.html) only when:

• The user explicitly asks for HTML.
• The artifact will be shared via a static-site / preview channel where Markdown rendering is unavailable.

Starter templates live next to this skill:

• template.md — copy when creating the file the first time.
• template.html — copy when the user opts into HTML.

Copy the relevant template verbatim into the project, then fill it in. Do not invent a new layout per project.

Where to Put the File

• Default location: project root.
• For monorepos, place it at the feature scope root (the package/app directory that owns the SPEC), not the repo root.
• Default git policy: do not commit the file. On first creation, append implementation-notes.md (and .html if used) to the project's .gitignore. If the user later asks to commit it, remove the ignore entry — do not commit silently.

Required Sections

The notes file must contain these four sections (templates already include them):

Entry Format

Each entry must include:

• Title — short, scannable.
• Status — see lifecycle below. Required.
• Spec area / feature — which part of the SPEC this touches.
• Timestamp — ISO 8601 with offset (e.g. 2026-05-25T14:30+09:00). Required, not optional.
• Body — concise explanation, typically 1–4 sentences.

Status Lifecycle

open ──► accepted ──► resolved
              │
              └──► changed ──► accepted | resolved

Never delete an entry. If a decision is reversed, transition it through changed and add a new entry — the audit trail is the point.

Workflow

1. Read the SPEC and skim the codebase for likely ambiguity before writing code.
2. Copy the starter template into the project and append the file to .gitignore (unless told otherwise).
3. Seed the section headers, even if each section is initially empty.
4. Update notes before or alongside the code change whenever:
   • The spec has multiple valid interpretations.
   • A user-visible behavior is chosen without explicit spec language.
   • Codebase constraints force a different implementation than the spec implies.
   • A simpler / staged / lower-risk approach is chosen over a richer alternative.
   • A question remains but implementation proceeds on a reasonable assumption.
5. Do not log routine edits (renames, formatting, obvious refactors). Notes track judgments, not activity.
6. At the end, summarize the implemented behavior and list every entry still in open status or recently changed.

Verification Before Declaring Done

Run, in order, whichever exist in the project:

1. Type check (tsc, mypy, cargo check, etc.).
2. Lint (eslint, ruff, cargo clippy, etc.).
3. Tests relevant to the touched code.
4. Build (if the project produces an artifact).

If a step does not exist or cannot be run, state that explicitly in the wrap-up. For behavioral verification (actually exercising the feature in a running app), delegate to the verify or run skill.

Completion Criteria

The task is complete when all of the following hold:

• The SPEC implementation is done, or a clear blocker is recorded as an open entry.
• implementation-notes.md (or .html) exists and reflects every known decision, deviation, tradeoff, and open question.
• Verification appropriate to the project has been run, or its absence is stated explicitly.
• The final response summarizes the implemented behavior and explicitly lists unresolved open items.

Default Starting Prompt

When invoked right after grill-me:

Implement the clarified SPEC. Maintain a live implementation-notes.md recording every meaningful point where the implementation differs from, interprets, or extends the specification. Use the sections, entry format, and status lifecycle defined in this skill. No spec is complete — surface ambiguities and unexpected constraints as you find them, and keep your assumptions visible for continuous feedback.