A workflow for writing a detailed plan for one software component and a matching document describing how to test it. It uses the project's architecture plan, plan index, dependencies, and referenced requirements as context.

Use it to specify modules, interfaces, data types, algorithms, protocols, connections to other components, and the tests that will verify the component.

It turns high-level architecture into concrete implementation guidance before coding starts.

plan-draft — Skill for Claude Code by dcosson/h2

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.

Any agent

npx skills add dcosson/h2 --skill plan-draft

Clone the repo

git clone --depth 1 https://github.com/dcosson/h2

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/dcosson/h2/plan-draft/github.svg)](https://agentmods.dev/skills/dcosson/h2/plan-draft)

Your own site

<a href="https://agentmods.dev/skills/dcosson/h2/plan-draft"><img src="https://agentmods.dev/badge/skills/dcosson/h2/plan-draft/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/dcosson/h2/plan-draft"><img src="https://agentmods.dev/badge/skills/dcosson/h2/plan-draft.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 839 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00031	$0.00839
Opus 5.5	$0.00012	$0.00336
Sonnet 5.5	$0.00006	$0.00168
Haiku 4.5	$0.00003	$0.00084

Measured 1mo ago against content hash 04752c3537ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

plan-draft 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 1mo 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.

internal/config/templates/styles/opinionated/skills/plan-draft/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Plan Draft

Write a plan doc and its companion test harness doc for a single component.

Inputs

$0: Doc identifier (e.g., 04d-oltp-sql-engine)
$1 (optional): Scope description — what the plan should cover
Plans directory: docs/plans/ (or the project's established plans directory)

Phase 1: Read Context

Read docs/plans/00-plan-index.md to understand dependencies and scope
Read docs/plans/00-architecture.md for architectural context
Read all prerequisite/dependency docs listed in the plan index for this component
Read any shaping docs or API contracts referenced

Phase 2: Write Plan Doc

Write docs/plans/$0.md following project conventions:

Architecture summary with mermaid diagrams (component, sequence, state where relevant)
Package/module structure and import flow
API/interface definitions (fully specified, not hand-waved)
Major types, structs, components with properties and key methods
Detailed design for all non-trivial algorithms and protocols
Connected Components — list which other components this plan connects to (its seams), with the interface at each boundary (function signatures, wire protocols, shared types, message formats)
Acceptance Criteria — 3-8 end-user-facing scenarios that prove the component works in the real system, not just in isolation. Each scenario must cross at least one component boundary. Format: scenario name, steps using the end-user interface (CLI, API, web UI, mobile — whatever the product exposes), expected outcome. These are NOT internal API tests; they verify behavior as a user would experience it.
Testing section (unit, component, integration strategy). For every test category, specify: (1) where test files will live (exact package/directory paths), (2) which make target or test suite they roll up into, (3) whether they run in CI PR checks, nightly, or on-demand. Tests without a home and a runner don't get run.
URP (Unreasonably Robust Programming) section — concrete commitments, not wishlists. Each item must specify exactly what will be built, where it fits in the implementation, and how it will be tested. If it's not concrete enough to implement directly from the plan, cut it or make it concrete.
Extreme Optimization section — same standard: commit to specific techniques with design details, or cut them.
Alien Artifacts section — same standard: commit to specific techniques with design details, or cut them.

Read the full file on GitHub · 66 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.

1mo ago First seen · 66 lines · 31 tokens per session scan A 04752c3537ec

Subscribe to this mod's changes

plan-draft is a skill published in the GitHub repository dcosson/h2 (163 stars, last pushed yesterday), licensed MIT. It adds 31 tokens to every session and 839 once invoked, about $0.0001 per session on Opus 5.5. 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.

Planning Testing

research-engineer

An uncompromising Academic Research Engineer. Operates with absolute scientific rigor, objective criticism, and zero flair. Focuses on theoretical correctness, formal verification, and optimal implementation across any required technology.

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Compare extracts from two Tika builds over a corpus to detect regressions in content, encoding, exceptions, and embedded-document handling. Use for "compare before/after extracts", "eval this change against the corpus".

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davidondrej/skills · 68 tokens

plan-draft