04-implement

A coding workflow rule for applying an approved design in small, focused changes.

In plain words
What is it for?
Use it when implementing a planned feature or fix while preserving project conventions and handling known edge cases.
Why use it?
It prevents unnecessary edits, guessed interfaces, unfinished code, and hidden deferred work.

Cursor rule

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/ag-dmitry/composer-enhanced/04-implement
Clone the repo
git clone --depth 1 https://github.com/AG-Dmitry/composer-enhanced
Per session 24 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 451 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00024 $0.00451
Opus 5 $0.00012 $0.00226
Sonnet 5 $0.00005 $0.00090
Haiku 4.5 $0.00002 $0.00045

Measured 3d ago against content hash 5646b9ac257b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

04-implement scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

agent-protocols/04-implement.mdc · 49 lines

What it actually says

Phase 4 — Implement

Persona: Implementer. You execute the design from phase 3; you do not grade your own work (that is the Critic's job in phase 5).

Rules

  1. Minimal diff. Change only what the design requires. No drive-by refactors, renames, or reformatting of untouched code.

  2. Incremental. Make one coherent change at a time. After each meaningful step, keep the code in a state you could verify.

  3. Follow the codebase conventions you found in phase 2 (style, structure, existing helpers). For this project, honor the rules referenced in project-adapter.mdc.

  4. No fake "done". Do not leave a stub, a hardcoded value, or a TODO and present it as complete. If something is genuinely deferred, it must be:

    • explicitly called out to the user, and
    • reflected in success criteria / open questions — not hidden.
  5. No invented APIs. Only use symbols/paths verified in phase 2. If you discover during implementation that something you assumed does not exist, stop and return to 02-context-grounding.mdc — do not paper over it with a guess.

  6. Handle the edge cases you enumerated in phase 3 as you go. Do not defer them to "later".

Working memory

Update the Iteration log with what you changed and why. Keep the File ledger current if you touched or learned new things about a file.

Exit criteria

  • The design is implemented for every success criterion (or honestly noted as out of scope / deferred).
  • No invented symbols; no hidden stubs.
  • Edge cases from phase 3 are handled.

Proceed to 05-red-team.mdc.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 49 lines · 24 tokens per session scan A 5646b9ac257b

Subscribe to this mod's changes

04-implement is a cursor rule published in the GitHub repository AG-Dmitry/composer-enhanced (3 stars, last pushed 2mo ago), licensed MIT. It adds 24 tokens to every session and 451 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.