claude-plan

claude-plan is a skill for Codex from Ancienttwo/repo-harness. It costs 128 tokens per session (3,004 once invoked), scanned A, original, MIT.

A cross-check that asks Anthropic Claude, a different AI model provider, for an architecture or implementation plan while another coding agent is working.

In plain words
What is it for?
Use it to review risky migrations, cross-module interfaces, or other design forks before committing to one approach.
Why use it?
It adds a second viewpoint when an important design choice has several plausible answers or could be costly to undo.

Skill for Codex

Written for Codex: reads ~/.codex or $CODEX_HOME. Also seen: reads .claude/ paths; names the ExitPlanMode tool; mentions Claude Code.

Good fit Use it to review risky migrations, cross-module interfaces, or other design forks before committing to one approach.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ancienttwo/repo-harness/claude-plan
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 Ancienttwo/repo-harness --skill claude-plan
Clone the repo
git clone --depth 1 https://github.com/Ancienttwo/repo-harness

Made for: Codex.

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.

agentmods badge for claude-plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/ancienttwo/repo-harness/claude-plan/github.svg)](https://agentmods.dev/skills/ancienttwo/repo-harness/claude-plan)
Your own site
<a href="https://agentmods.dev/skills/ancienttwo/repo-harness/claude-plan"><img src="https://agentmods.dev/badge/skills/ancienttwo/repo-harness/claude-plan/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.

agentmods 80×15 button for claude-plan

Your own site · 80×15
<a href="https://agentmods.dev/skills/ancienttwo/repo-harness/claude-plan"><img src="https://agentmods.dev/badge/skills/ancienttwo/repo-harness/claude-plan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,004 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00128 $0.03004
Opus 5 $0.00064 $0.01502
Sonnet 5 $0.00026 $0.00601
Haiku 4.5 $0.00013 $0.00300

Measured 10d ago against content hash 2b095e41b4ba, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

claude-plan 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 10d 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.

assets/skills/claude-plan/SKILL.md · 272 lines

How it starts

The opening of the file, as written. The whole thing — 272 lines — stays where its author put it; the contents beside it link to each section on GitHub.

claude-plan — independent plan from Claude's plan mode

The host model planning its own work shares its own blind spots. A different-vendor model (Anthropic Claude, pinned to Fable) has a different training distribution, so where its plan diverges from yours is exactly where to dig. This skill runs the Claude Code CLI (claude -p) in Claude's native plan mode — read-only at the permission layer, with Claude's internal research-then-plan steering — and presents the plan verbatim.

The consult is stateless: Claude cannot see the host session transcript. Everything it needs must travel in the decision brief. If you cannot write the brief, the question is not ready to be asked — that filter is a feature.

When to use

  • Mid-execution, a design fork appears that the host should not settle unilaterally (irreversible structure, cross-module contract, risky migration).
  • A high-stakes decision needs a cross-vendor second plan before committing.

When NOT to use

  • Routine planning: use the host's own plan tooling (Codex Plan mode, /think).
  • Planning known before the task starts: plan in a Claude session directly and hand off via a file-backed plan; do not call back mid-run.
  • Anything answerable by reading the repo for five minutes.

Fable shares the main Claude quota pool — every consult is a full session. One consult per fork; do not iterate plans through repeated calls.

Step 0 — Preflight (binary)

command -v claude >/dev/null 2>&1 || {
  echo "[claude-plan] Claude Code CLI not found. Install from https://claude.com/claude-code (then sign in). Skipping."
  exit 0
}

If this prints the skip message, tell the user Claude Code is not installed and stop.

Step 1 — Compose the decision brief

Write the brief yourself (the host orchestrator), with every section filled concretely. The brief follows the shared architect consultation packet shape, so the same packet can be sent unchanged to any other external consultation track. Claude may read repository files for context, so cite paths instead of pasting whole files; paste only short excerpts or a scoped diff when the relevant state is not on disk.

Read the full file on GitHub · 272 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. 10d ago First seen · 272 lines · 128 tokens per session scan A 2b095e41b4ba

Subscribe to this mod's changes

claude-plan is a skill published in the GitHub repository Ancienttwo/repo-harness (431 stars, last pushed today), licensed MIT. It adds 128 tokens to every session and 3,004 once invoked, about $0.0006 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.