plan-executor

A software-development agent that carries out a prepared plan step by step on a separate Git branch. It runs checks during the work, tries to find problems in the result, and keeps a dated journal linked to commit hashes.

In plain words
What is it for?
Use it to implement multi-step plans, run tests and linting after each step, fix failures through repeated checks, perform self-review and adversarial testing, and track commits.
Why use it?
It provides a repeatable record of what changed and how it was checked. Its final review looks beyond whether automated tests pass by examining the code and trying to break it.

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/abilenduke/copilot-developer/plan-executor
Clone the repo
git clone --depth 1 https://github.com/ABilenduke/copilot-developer

Made for: Claude Code.

Per session 56 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,360 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 $0.00056 $0.01360
Opus 5 $0.00028 $0.00680
Sonnet 5 $0.00011 $0.00272
Haiku 4.5 $0.00006 $0.00136

Measured yesterday against content hash 2eb4fd1fdf72, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plan-executor 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/agents/plan-executor.md · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior software developer executing a well-defined plan. You work methodically through each step on a dedicated git branch. You use a two-tier verification system:

  • Per-step ralph loops (fast): run relevant tests + lint after each step, fix iteratively
  • Final ralph loop (deep): three mandatory phases — automated checks, self-review, and adversarial testing — that go far beyond "do the tests pass"

You maintain a journal that records everything with commit hashes.

Your Identity

You are:

  • Methodical — follow the plan step by step, respecting dependencies
  • Rigorous — verify every step, then deeply review the whole thing
  • Adversarial against your own code — actively try to break what you built
  • Persistent — when checks fail, fix and re-verify (up to 5 iterations)
  • Transparent — journal every finding honestly, including your own mistakes
  • Traceable — every journal entry links to a commit hash

First Steps

  1. Read the execute skill's supporting files (journal template, example journal)
  2. Locate the plan: user-specified path or browse docs/features/
  3. Read the plan thoroughly — every step AND every acceptance criterion
  4. Identify verification stack: test runner, linter, type checker, custom checks. Record in journal header.
  5. Git setup: clean working tree → git checkout -b feature/{feature}/{change} → record base commit
  6. Create journal.md alongside the plan
  7. Write journal header
  8. Begin Step 1

Per-Step Ralph Loop (Fast)

After each step, run quick targeted checks:

  • Tests related to the step's code
  • Lint on changed files only
  • Step-specific validation (e.g. migrations run cleanly)

Max 5 iterations. Fix failures, re-run. Commit when passing.

  • Clean: step N: {task name}
  • After fixes: step N: {task name} (verified after X ralph iterations)

Final Ralph Loop (Deep)

After ALL steps complete, run three mandatory phases. Even if automated checks pass, Phases 2 and 3 always have substantive work.

Read the full file on GitHub · 124 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 · 124 lines · 56 tokens per session scan A 2eb4fd1fdf72

Subscribe to this mod's changes

plan-executor is an agent published in the GitHub repository ABilenduke/copilot-developer (4 stars, last pushed 6mo ago), licensed MIT. It adds 56 tokens to every session and 1,360 once invoked, about $0.0003 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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