plan:new

A project-planning workflow for new projects or substantial changes that creates a written specification and implementation plan before coding.

In plain words
What is it for?
Clarifying scope and success criteria, exploring the codebase, writing project specs and plans, and getting an adversarial review before implementation.
Why use it?
It turns an unclear idea into agreed requirements and a reviewed plan, while leaving small fixes and simple edits out of the process.

Skill for Claude CodeCodex

Part of the plan plugin — 4 skills shipped together

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/franzos/claude-plugins/plan-new
Any agent
npx skills add franzos/claude-plugins --skill plan-new
Clone the repo
git clone --depth 1 https://github.com/franzos/claude-plugins

Made for: Claude Code, Codex.

Or install plan, the plugin that ships this one along with the rest of its 4 skills.

Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 927 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 $0.00072 $0.00927
Opus 5 $0.00036 $0.00464
Sonnet 5 $0.00014 $0.00185
Haiku 4.5 $0.00007 $0.00093

Measured 2d ago against content hash 59f6de1b9e15, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

plan:new 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 2d 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.

plugins/plan/skills/plan-new/SKILL.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Planning a change

$KB is your knowledge-base root: a directory outside the working repo holding <project>/specs/, <project>/plans/ and <project>/checkpoints/. Point at it from your CLAUDE.md. Keeping these out of the repo keeps process artifacts from leaking into it, and the knowledge survives clones, branches and machines.

Produces two files in the knowledge base and nothing else. No implementation code is written in this skill.

Stop and say so if the change is small or mechanical (a bug fix, a one-file tweak, a rename). Those do not need a plan.

0. Locate the project

Project name is the repo's folder name, lowercase kebab-case. Everything lands under $KB/<project>/.

Pick a slug now (kebab-case, describes the change, no date). The spec, the plan, and every checkpoint share it.

1. Q&A before anything else

Ask the user about what is underspecified. Use AskUserQuestion for real forks; plain prose for open questions. Batch related questions rather than drip-feeding them.

Ask about: the actual problem being solved, scope boundaries (what is explicitly not in this change), constraints, what "done" looks like, and anything the codebase cannot tell you.

Do not assume and do not proceed on a guess. If two readings of the request lead to materially different work, that is a question, not a judgment call.

2. Understand what exists

For a brownfield change, dispatch feature-dev:code-explorer with a specific question - the feature to trace, the subsystem to map. Ask it to return the files that matter most, then read those directly.

Do not explore the codebase inline. That is what the agent is for.

Skip this for greenfield work.

3. Write the spec

$KB/<project>/specs/YYYY-MM-DD-<slug>.md

The spec is the what and why, authoritative over everything downstream. It carries: the problem, the decisions taken and their rationale, explicit non-goals, constraints, and open questions still outstanding. Prose over bullets where the reasoning matters.

Read the full file on GitHub · 78 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. 2d ago First seen · 78 lines · 72 tokens per session scan A 59f6de1b9e15

Subscribe to this mod's changes

plan:new is a skill published in the GitHub repository franzos/claude-plugins (1 stars, last pushed 21d ago), licensed MIT. It adds 72 tokens to every session and 927 once invoked, about $0.0004 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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