plan-agent-implementation

A guide for turning an approved software design into an ordered list of implementation tasks. Each task has a concrete result and a way to check it.

In plain words
What is it for?
Use it to choose the files or modules to change, order the work, add checkpoints, and verify progress during implementation.
Why use it?
It prevents teams from jumping into one large, vague coding task and exposes dependencies and risky assumptions early.

Skill for Claude CodeCodex

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 skills/bikeread/promethos/plan-agent-implementation
Any agent
npx skills add bikeread/promethos --skill plan-agent-implementation
Clone the repo
git clone --depth 1 https://github.com/bikeread/promethos

Made for: Claude Code, Codex.

Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 621 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 $0.00022 $0.00621
Opus 5 $0.00011 $0.00311
Sonnet 5 $0.00004 $0.00124
Haiku 4.5 $0.00002 $0.00062

Measured 3d ago against content hash 2445a8862147, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plan-agent-implementation 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.

skills/plan-agent-implementation/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Goal

Produce a clear implementation sequence that can be executed incrementally and verified along the way.

Inputs

  • Approved architecture
  • Relevant codebase context
  • Constraints on tooling, time, and verification

Non-Goals

  • Revisiting the architecture without evidence
  • Writing vague tasks that hide complexity

Workflow

Trigger signals

  • Architecture is approved but no build order exists
  • User says "接下来怎么搞" or "what do we build first"
  • The conversation is about to jump from design to code without a task breakdown

1. Freeze the implementation surface

Translate the architecture into concrete files, modules, or documents to create or modify, and assign each one a single responsibility. Success criteria: The work is decomposed into concrete units instead of one large implementation blob.

2. Define thin, verifiable tasks

Break the work into steps that each produce a visible result and can be checked independently. Success criteria: Each task is small enough to execute and verify without guessing hidden substeps.

3. Order tasks by dependency and risk

Sequence the work so foundations come first, risky assumptions are tested early, and later tasks build on already verified behavior. Success criteria: The task order reflects both dependency flow and risk reduction.

4. Attach verification to every stage

State the command, inspection, or artifact review that proves each stage is actually complete. Success criteria: The plan defines evidence for every meaningful step, not just activity labels.

5. Decide where reusable eval coverage is required

For any behavior change, recovery path, or safety-sensitive flow, state whether the implementation plan must add or refresh reusable regression or evaluation coverage. Success criteria: The plan makes explicit when verification ends at the current change and when it must be promoted into reusable eval coverage.

6. Check the plan against scope discipline

Review the plan for YAGNI violations, unresolved architecture questions, and tasks that are too vague or too broad. Success criteria: The final plan is narrow, executable, and aligned with the approved design.

Read the full file on GitHub · 84 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 84 lines · 22 tokens per session scan A 2445a8862147

Subscribe to this mod's changes

plan-agent-implementation is a skill published in the GitHub repository bikeread/promethos (33 stars, last pushed 5mo ago), licensed MIT. It adds 22 tokens to every session and 621 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 2026-08-30.

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