plan

plan is a skill for Claude Code, Codex from StarryCod/cogitum. It costs 19 tokens per session (457 once invoked), scanned A, a copy of plan, MIT.

A planning mode that creates a detailed Markdown plan in the project before any implementation begins. It is intended for users who want instructions and file-level planning rather than code changes.

In plain words
What is it for?
Preparing plans for code changes, documenting affected files, defining validation steps, and recording tradeoffs without implementing the work.
Why use it?
It gives developers an actionable record of the proposed work before anything is edited. This helps clarify assumptions, tests, risks, and open questions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents.

Good fit Preparing plans for code changes, documenting affected files, defining validation steps, and…

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

Made for: Claude Code, 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 plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/starrycod/cogitum/plan.svg)](https://agentmods.dev/skills/starrycod/cogitum/plan)
Your own site
<a href="https://agentmods.dev/skills/starrycod/cogitum/plan"><img src="https://agentmods.dev/badge/skills/starrycod/cogitum/plan.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 457 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.
Origin 81% copy Near-identical to another mod 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 $0.00019 $0.00457
Opus 5 $0.00010 $0.00229
Sonnet 5 $0.00004 $0.00091
Haiku 4.5 $0.00002 $0.00046

Measured 3d ago against content hash 6d8663bf23a7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

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 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.

Origin

This is a copy

81% identical to plan — 14 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

cogitum/data/skills/software-development/plan/SKILL.md · 59 lines

What it actually says

Plan Mode

Use this skill when the user wants a plan instead of execution.

Core behavior

For this turn, you are planning only.

  • Do not implement code.
  • Do not edit project files except the plan markdown file.
  • Do not run mutating terminal commands, commit, push, or perform external actions.
  • You may inspect the repo or other context with read-only commands/tools when needed.
  • Your deliverable is a markdown plan saved inside the active workspace under .cogitum/plans/.

Output requirements

Write a markdown plan that is concrete and actionable.

Include, when relevant:

  • Goal
  • Current context / assumptions
  • Proposed approach
  • Step-by-step plan
  • Files likely to change
  • Tests / validation
  • Risks, tradeoffs, and open questions

If the task is code-related, include exact file paths, likely test targets, and verification steps.

Save location

Save the plan with write_file under:

  • .cogitum/plans/YYYY-MM-DD_HHMMSS-<slug>.md

Treat that as relative to the active working directory / backend workspace. Cogitum file tools are backend-aware, so using this relative path keeps the plan with the workspace on local, docker, ssh, modal, and daytona backends.

If the runtime provides a specific target path, use that exact path. If not, create a sensible timestamped filename yourself under .cogitum/plans/.

Interaction style

  • If the request is clear enough, write the plan directly.
  • If no explicit instruction accompanies /plan, infer the task from the current conversation context.
  • If it is genuinely underspecified, ask a brief clarifying question instead of guessing.
  • After saving the plan, reply briefly with what you planned and the saved path.
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 · 59 lines · 19 tokens per session scan A 6d8663bf23a7

Subscribe to this mod's changes

plan is a skill published in the GitHub repository StarryCod/cogitum (11 stars, last pushed 3mo ago), licensed MIT. It adds 19 tokens to every session and 457 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 81% identical to plan, differing in 14 lines, and is treated as a copy.

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