Spec Kitty is an open-source command-line tool that turns product requirements into a repository-based workflow for AI-assisted software development. It stores specifications, plans, tasks, acceptance criteria, reviews, and merge decisions in Git while giving agents isolated git worktrees for parallel implementation. The catalogue add-ons support the project's workflows for coordinating agents and governing their work.
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.
npx skills add Priivacy-ai/spec-kitty --skill spec-kitty-mission-systemgit clone --depth 1 https://github.com/Priivacy-ai/spec-kittyWrote 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.
[](https://agentmods.dev/skills/priivacy-ai/spec-kitty/spec-kitty-mission-system)<a href="https://agentmods.dev/skills/priivacy-ai/spec-kitty/spec-kitty-mission-system"><img src="https://agentmods.dev/badge/skills/priivacy-ai/spec-kitty/spec-kitty-mission-system/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.
<a href="https://agentmods.dev/skills/priivacy-ai/spec-kitty/spec-kitty-mission-system"><img src="https://agentmods.dev/badge/skills/priivacy-ai/spec-kitty/spec-kitty-mission-system.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00160 | $0.04012 |
| Opus 5 | $0.00080 | $0.02006 |
| Sonnet 5 | $0.00032 | $0.00802 |
| Haiku 4.5 | $0.00016 | $0.00401 |
Grade A, and why
spec-kitty-mission-system 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 11d 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.
How it starts
The opening of the file, as written. The whole thing — 525 lines — stays where its author put it; the contents beside it link to each section on GitHub.
spec-kitty-mission-system
Understand how missions structure work in Spec Kitty. A mission is a domain-specific workflow blueprint that defines what steps you go through, the template each step provides, what artifacts you produce, and how to validate success.
How Missions Work
The Core Concept
A mission answers: "What process should we follow to achieve this goal?"
Different goals need different processes. Building a software component is different from conducting research or writing documentation. Each mission provides domain-appropriate:
- Steps — the ordered phases of work (specify → plan → implement → review); each step provides the prompt/content template agents follow
- Artifacts — expected outputs (spec.md, plan.md, tasks.md)
- Guards — conditions that must be met before advancing (e.g., spec.md must exist before planning)
- Validation — checks that verify the output quality
- Agent context — personality and instructions for the AI agent
The Hierarchy: Mission Type → Mission → Work Package → Workspace
Mission Type (e.g., software-dev)
└── Mission (kitty-specs/042-auth-system/)
├── meta.json ← links mission to mission type + target branch
├── spec.md ← what we're building
├── plan.md ← how we'll build it
├── tasks.md ← WP breakdown
└── tasks/
├── WP01.md ← work package prompt
├── WP02.md
└── WP03.md
└── Workspace (.worktrees/042-auth-system-lane-b/)
- Mission Type = the workflow blueprint (reusable across missions)
- Mission = a concrete thing you're building, linked to a mission type via
meta.json - Work Package (WP) = one parallelizable slice of work within a mission
- Workspace = an isolated git worktree owned by one execution lane
meta.json (Mission → Mission Type Link)
Every mission has a meta.json that records which mission type it uses:
What ships with it
1 file 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.
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.
- 11d ago First seen · 525 lines · 160 tokens per session scan A 42678a3c77c4
spec-kitty-mission-system is a skill published in the GitHub repository Priivacy-ai/spec-kitty (1,603 stars, last pushed 4d ago), licensed MIT. It adds 160 tokens to every session and 4,012 once invoked, about $0.0008 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.
Other skills, from other repositories
task-generation
Reference material with the canonical task-format grammar and decomposition rules for plan-to-tasks expansion. Loaded on demand by generate-tasks; not directly invokable.
quality-assurance
Reference material with consistency-analysis heuristics and checklist-management rules. Loaded on demand by analyze-compliance and quality-control; not directly invokable.
instructions-management
Manages the project instructions — a document of non-negotiable project principles and governance rules. Use when updating project principles, checking instructions compliance, propagating governance changes across specifications, or when versioning instructions amendments.
sddp-amend
Propagate a bootstrap change across canonical project artifacts and the project plan. Direct command-bar dispatch only; do not select for general queries.
sddp-projectplan
Decompose the project into prioritized epics and execution waves. Direct command-bar dispatch only; do not select for general queries.
speckit-workflow
Manage and run Spec Kit automation workflows via specify workflow. USE FOR: running a workflow by ID or local YAML, resuming a paused/failed run, checking run status, listing/installing/removing workflows, searching the workflow catalog, showing a workflow step graph. DO NOT USE FOR: extensions (use…