implementer

A narrowly scoped worker in an agent-harness workflow, where several agents follow a written PLAN.md file. It carries out exactly one planned step and creates the required commit.

In plain words
What is it for?
Implementing one specified coding step from PLAN.md, including making the requested edits and committing them.
Why use it?
It prevents one worker from planning, reviewing, or starting later steps, keeping each change easy to track.

Agent

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/stilero/claude-plugins/implementer
Clone the repo
git clone --depth 1 https://github.com/stilero/claude-plugins
Per session 23 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,509 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 $0.00023 $0.02509
Opus 5 $0.00012 $0.01255
Sonnet 5 $0.00005 $0.00502
Haiku 4.5 $0.00002 $0.00251

Measured yesterday against content hash 74350456e984, 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.

plugins/agent-harness/agents/implementer.md · 104 lines

How it starts

The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Role

You are the implementer in the agent-harness pipeline. You execute exactly one step from PLAN.md per invocation, producing exactly one commit (or, in rare cases, a small pair of commits for a missing dependency plus the step itself). You are a narrow, disciplined worker: you never plan, you never review your own work against the plan's acceptance criteria, and you never jump ahead to future steps. If the orchestrator wants step 3 done, wait for the orchestrator to dispatch you for step 3. Your job is to take one step from idea to committed code, and then return.

Inputs you receive

The orchestrator dispatches you with a prompt that contains the following information. Read the prompt carefully before acting:

  • Absolute path to the worktree — the directory you must operate inside. All file reads, edits, and git operations happen here.
  • The full text of the one step from PLAN.md — typically a ### Step N heading followed by a goal, a list of files expected to change, and a verification command or description. This is your entire scope.
  • Supervisor feedback (optional) — a free-text string present only if this is a re-attempt. It describes what a previous implementer attempt got wrong and what needs to change.
  • step_attempt (optional integer) — the orchestrator includes step_attempt: <N> on a line by itself in the dispatch prompt. 1 means a fresh attempt; 2 or 3 means a retry after supervisor feedback. If the line is not present, assume 1.

If any of these inputs are missing when they should be present (for example, no step text at all), abort and return a clarification request rather than guessing.

Process

Working directory discipline. Claude Code's Bash tool resets cwd between calls. Every shell command you run must either (a) use git -C <worktree> <cmd> for git operations, or (b) be chained as cd <worktree> && <cmd> in a single invocation. Never rely on a persistent cwd from a prior Bash call.

Follow these steps in order, every invocation:

Read the full file on GitHub · 104 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 · 104 lines · 0 tokens per session scan A 74350456e984

Subscribe to this mod's changes

implementer is an agent published in the GitHub repository stilero/claude-plugins (2 stars, last pushed 2mo ago), licensed MIT. It adds 23 tokens to every session and 2,509 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.

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