openspec-propose

openspec-propose is a skill for Claude Code from Fission-AI/OpenSpec. It costs 66 tokens per session (3,497 once invoked), scanned A, a copy of openspec-ff-change, MIT.

A planning workflow for describing a proposed software change and producing a proposal, design, specification updates, and implementation tasks.

In plain words
What is it for?
Use it to prepare a complete, reviewable plan for a new feature or other change. Implementation starts later through a separate workflow.
Why use it?
It turns a rough request into a structured plan without changing project code, so the work can be reviewed before implementation begins.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to prepare a complete, reviewable plan for a new feature or other change. Implementation starts later through a separate workflow.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fission-ai/openspec/openspec-propose
About the project

OpenSpec is a specification-driven development framework that records software requirements and implementation plans as readable Markdown artifacts. It helps developers and AI coding assistants agree on what should be built before code is written, including work spanning multiple repositories. The catalogue add-ons provide workflow skills and instructions for using OpenSpec.

Fission-AI/OpenSpec · 72,052 stars · on GitHub · openspec.dev

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 Fission-AI/OpenSpec --skill openspec-propose
Clone the repo
git clone --depth 1 https://github.com/Fission-AI/OpenSpec

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.

agentmods badge for openspec-propose

README.md
[![agentmods](https://agentmods.dev/badge/skills/fission-ai/openspec/openspec-propose/github.svg)](https://agentmods.dev/skills/fission-ai/openspec/openspec-propose)
Your own site
<a href="https://agentmods.dev/skills/fission-ai/openspec/openspec-propose"><img src="https://agentmods.dev/badge/skills/fission-ai/openspec/openspec-propose/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 openspec-propose

Your own site · 80×15
<a href="https://agentmods.dev/skills/fission-ai/openspec/openspec-propose"><img src="https://agentmods.dev/badge/skills/fission-ai/openspec/openspec-propose.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,497 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
  • Socket pass 17 Sept 2026
  • Snyk pass 17 Sept 2026
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Memory Poisoning · line 118
    Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.
    Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
How audits are shown
Origin 84% 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 $0.00066 $0.03497
Opus 5.5 $0.00026 $0.01399
Sonnet 5.5 $0.00013 $0.00699
Haiku 4.5 $0.00007 $0.00350

Measured 29d ago against content hash 7848351e7c51, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

openspec-propose 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 29d 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

84% identical to openspec-ff-change — 76 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.

skills/openspec-propose/SKILL.md · 174 lines

How it starts

The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Propose a new change - create the change and generate all artifacts in one step.

Planning boundary: This workflow creates planning artifacts only. The user request that selected or triggered this workflow authorizes planning only, even if it asks to build or fix something. Do not edit project code. After the planning artifacts are complete, stop. Do not start implementation in the same response, even if the initial request asks for it. Wait for a new user request after the artifacts are presented; then start the apply workflow.

I'll create a change with the artifacts your schema defines. With the default spec-driven schema that is:

  • proposal.md (what & why)
  • specs/<capability-path>/spec.md (what the system must do - a delta, not the main spec)
  • design.md (how)
  • tasks.md (implementation steps)

<capability-path> is the spec directory relative to specs/ (for example, user-auth or identity/user-auth). Preserve an existing capability's full path and follow the project's established organization for new capabilities.

When the user is ready to implement, they must start the apply workflow explicitly.


Store selection: If the user names a store (a store is a standalone OpenSpec repo registered on this machine) or the work lives in one, run openspec store list --json to discover registered store ids, then pass --store <id> on the commands that read or write specs and changes (new change, status, instructions, list, show, validate, archive, doctor, context, schemas, view). Once selected, treat --store <id> as sticky for the rest of the workflow. Every unscoped example of those commands below is shorthand: before running it, append the flag. For example, run openspec status --change "<name>" --json --store "<id>", not the unscoped form shown below. Other commands do not take the flag. Hints printed by commands already carry the flag; keep it on follow-ups. Without a store, commands act on the nearest local openspec/ root.

Project check: These steps expect a project that already uses OpenSpec. Before the first step that writes anything (new change, archive, sync specs, or authoring an artifact file), confirm the project has a root: run openspec list --json (with --store <id> when a store is selected, since the store is then the root) and read root. A root object means the project is set up. "root": null means it is not - there is no openspec/ directory here, and a write such as openspec new change would create one as a side effect. The command also exits non-zero, which is that answer rather than a broken CLI, so read the JSON instead of retrying or working around it.

One "root": null is not about setup: when a status error message starts with Declared in or Invalid store declaration in and names this project's openspec/config.yaml (or config.yml), the project does use OpenSpec through a store it declares, which this machine cannot resolve (the store is not registered, or the store: line is malformed). Do not treat it as uninitialized and skip the branches below: stop before writing and show the user that error's message and fix.

Otherwise, with no root, what happens next depends on how this workflow was reached:

  • Auto-selected: you chose this workflow yourself, without the user naming OpenSpec, naming this skill, or running its slash command. Stop using OpenSpec and answer the request normally, as you would with no OpenSpec installed. Do not ask them to set anything up and do not mention OpenSpec setup.
  • Explicit OpenSpec request: the user named OpenSpec, named this skill, or ran its slash command. Stop before writing and ask how to proceed: set this project up (openspec init), target a store they already have (--store <id>), or continue without OpenSpec for this request. Wait for their answer.

In both branches, never create the root as a side effect: do not run openspec init until the user asks for it, do not hand-create openspec/ files, and do not let a command create it.

Read the full file on GitHub · 174 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. 29d ago Changed · +11 lines · +19 tokens per session 7848351e7c51
  2. 1mo ago Changed · +10 lines af5f5e5ebd0c
  3. 1mo ago Changed · +4 lines f4ef2689aa61
  4. 1mo ago First seen · 149 lines · 47 tokens per session scan A c0537ce31111

Subscribe to this mod's changes

openspec-propose is a skill published in the GitHub repository Fission-AI/OpenSpec (72,052 stars, last pushed today), licensed MIT. It adds 66 tokens to every session and 3,497 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 84% identical to openspec-ff-change, differing in 76 lines, and is treated as a copy.

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