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prospec: Skill for Claude Code

.agents/skills/prospec-plan/SKILL.md

prospec-plan is a skill for Claude Code, Codex from benwu95/prospec. It costs 67 tokens per session (6,064 once invoked), scanned A, original, MIT.

A planning tool that turns a user story—a plain-language description of a desired feature—into a technical plan and a change specification. It uses the Prospec command-line program to create plan.md and delta-spec.md.

In plain words
What is it for?
Use it to plan a feature, define its technical changes, and prepare work for implementation. It also supports architecture and technical-planning requests.
Why use it?
It gives coding agents and developers a shared, written plan before code changes begin. This reduces the risk of missed tasks or unclear implementation decisions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; installed under .agents/ (shared by several agents).

This is benwu95/prospec's own configuration. It tells Claude Code and Codex how to work on prospec itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything prospec configures →

not rated 6repo changed 4d ago A scan 67 tokens original MIT
View source ↗ benwu95/prospec benwu95.github.io
Reuse

Borrowing it

Nothing to install: this file belongs to benwu95/prospec. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/benwu95/prospec/main/.agents/skills/prospec-plan/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/benwu95/prospec

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.

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README.md
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Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,064 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 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 $0.00067 $0.06064
Opus 5.5 $0.00027 $0.02426
Sonnet 5.5 $0.00013 $0.01213
Haiku 4.5 $0.00007 $0.00606

Measured 4d ago against content hash 122c8c56fced, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

prospec-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 4d 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.

.agents/skills/prospec-plan/SKILL.md · 271 lines

How it starts

The opening of the file, as written. The whole thing — 271 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prospec Plan Skill

Activation

When triggered, briefly describe:

  • That you'll read the proposal.md and design an implementation plan
  • You'll produce both plan.md and delta-spec.md
  • Knowledge will be loaded progressively (Layer 1 then Layer 2 as needed)

Language Policy

Write each generated document in the language the Constitution's Language Policy rule assigns to its path — change artifacts and their archived summaries in the project's artifact language, the trust zone (Knowledge base, Feature Specs, index) in English. One skill run may write both. Free text you pass the CLI that lands in a change artifact follows the artifact language too, leaving its paths, commands, enum values and the fixed prefixes the CLI matches untranslated. Keep code, identifiers, technical terms, and git commit messages in English.

CLI Prerequisite (required)

The prospec CLI is a required file for this skill — its deterministic steps call prospec commands. Probe BEFORE any other step; there is no manual fallback.

  1. Run prospec --version (Bash).
  2. Command not found / not executable → STOP. Ask the user to install the prospec standalone executable — the one-click installer script from the project README (macOS/Linux install.sh, Windows install.ps1) or a release binary from GitHub Releases; prospec is NOT published to npm. Then re-run this skill.
  3. Version older than 2.10.0 → STOP. Report the installed vs required version and ask the user to upgrade, then re-run this skill.

Hand-executing a CLI-owned mutation is NEVER the fallback — that re-introduces the nondeterministic serialization this contract exists to remove.

Startup Loading

  1. [STABLE] Run prospec constitution show --station plan (Bash)
  2. [DYNAMIC] Read .prospec/changes/[name]/proposal.md — parse User Stories and acceptance scenarios
  3. [DYNAMIC] Read prospec/index.md — identify related modules (Layer 1)
  4. [DYNAMIC] Run prospec spec show <feature> --story <ids> (Bash) — features from prospec/ai-knowledge/feature-map.yaml, ids from that spec's story list
  5. [DYNAMIC] Read prospec/specs/product.md — understand product-level overview and feature map
  6. [DYNAMIC] Run prospec learn playbook --station plan --modules <related_modules> — _playbook.md catalog + station bodies

Read the full file on GitHub · 271 lines

Files

What ships with it

6 files 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. 4d ago Changed · -2 lines 122c8c56fced
  2. 5d ago Changed · -7 lines 4ae8bd21bdfd
  3. 6d ago Changed · +13 lines 69b7cad607ff
  4. 9d ago Changed 1a21fac47fb1
  5. 12d ago Changed ed2c01db59ab
  6. 13d ago Changed 2487b21676ec
  7. 20d ago Changed 21e1bc23515b
  8. 23d ago Changed a4d323f40b71
  9. 25d ago Changed a833bb6443bd
  10. 27d ago First seen · 267 lines · 67 tokens per session scan A 9a77723fea77

Subscribe to this mod's changes

prospec-plan is a skill published in the GitHub repository benwu95/prospec (6 stars, last pushed yesterday), licensed MIT. It adds 67 tokens to every session and 6,064 once invoked, about $0.0003 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 2026-08-31.

Planningagentic-codingai-coding-assistantai-knowledgeprogressive-disclosuresddspec-driven-development
Related

prospec-plan compared with skills from other repositories

prospec-plan next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
prospec-planbenwu95/prospecSkill6yesterdayMITA67Claude Code, Codex
ospec-goalclawplays/ospecSkill3902mo agoMITA29Codex
ospecclawplays/ospecSkill3902mo agoMITA26Claude Code, Codex
ospec-changeclawplays/ospecSkill3902mo agoMITA18Codex
review-spdzhu1090093659/spec_driven_developSkill9933mo agoMITA72Claude Code
deep-discusszhu1090093659/spec_driven_developSkill9933mo agoMITA181Claude Code
spec-driven-developzhu1090093659/spec_driven_developSkill9933mo agoMITA148Claude Code