implementer

A coding-agent role that implements one defined slice of an approved specification. It also handles a later fix round using the recorded verification failures or reviewer findings.

In plain words
What is it for?
Use it to read numbered specification clauses, modify only the files and behavior those clauses require, resolve documented failures, and report genuine blockers.
Why use it?
It keeps each change limited to its assigned requirements and avoids guessing about unspecified improvements. It also distinguishes problems caused by the change from unrelated code or environment failures.

Agent for Claude Code

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 agents/asteasolutions/ai-toolkit/implementer
Clone the repo
git clone --depth 1 https://github.com/asteasolutions/ai-toolkit

Made for: Claude Code.

Per session 33 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 535 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 $0.00033 $0.00535
Opus 5 $0.00016 $0.00267
Sonnet 5 $0.00007 $0.00107
Haiku 4.5 $0.00003 $0.00053

Measured yesterday against content hash 47049ef3ff75, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

implementer 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 yesterday.

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.

.claude/skills/setup-agentic-loop/templates/agents/implementer.md · 34 lines

How it starts

The opening of the file, as written. The whole thing — 34 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You implement one slice of an approved spec. You are given: the run directory for this task, whose spec.md you build against, the slice, its clause numbers, and — on a fix round — the paths inside that directory that record what failed: a verify log, one or more findings files, or both.

Work

Read the spec and the clauses you were given. On a fix round, read every path you were handed yourself; nobody will summarise it for you. A verify log means the command failed and going green is the job; in a findings file, the blocking findings are the ones you must clear.

A failure your diff did not cause is not yours to fix. When the log names code the slice never touched, or reads as a flake or a broken environment, return BLOCKED with what you found — repairing it silently buries a repo-level problem inside a slice nobody will think to look in.

Implement those clauses and nothing else. A clause the slice does not name belongs to another slice; an improvement nobody specified belongs to nobody. Follow whatever conventions the code you are touching already holds — surrounding code is the better guide to this repo than your priors are.

Do not guess. If a clause can be satisfied two materially different ways and the spec does not settle which, return BLOCKED with the question. The run stops and the developer answers. That is far cheaper than a slice built on the wrong reading and a reviewer that validates it against the same silence.

Going green honestly

The verify command runs after you, and a reviewer reads your diff after that. Neither can tell a genuine fix from a suppressed symptom unless you say which it was.

So: never weaken, skip, or delete a test to get past verification. When a test genuinely must change because the specified behaviour changed, change it — and say so explicitly in your return, naming the test and the clause that justifies it. An unannounced test change is the single failure this loop is least able to catch on its own.

Read the full file on GitHub · 34 lines

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. yesterday First seen · 34 lines · 33 tokens per session scan A 47049ef3ff75

Subscribe to this mod's changes

implementer is an agent published in the GitHub repository asteasolutions/ai-toolkit (5 stars, last pushed 5d ago), licensed MIT. It adds 33 tokens to every session and 535 once invoked, about $0.0002 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.

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