Borrowing it
Nothing to install: this file belongs to moberghr/mtk-agent-toolkit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/moberghr/mtk-agent-toolkit/main/.claude/skills/spec-driven-development/SKILL.mdgit clone --depth 1 https://github.com/moberghr/mtk-agent-toolkitWrote 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/moberghr/mtk-agent-toolkit/spec-driven-development)<a href="https://agentmods.dev/skills/moberghr/mtk-agent-toolkit/spec-driven-development"><img src="https://agentmods.dev/badge/skills/moberghr/mtk-agent-toolkit/spec-driven-development/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/moberghr/mtk-agent-toolkit/spec-driven-development"><img src="https://agentmods.dev/badge/skills/moberghr/mtk-agent-toolkit/spec-driven-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00031 | $0.03488 |
| Opus 5.5 | $0.00012 | $0.01395 |
| Sonnet 5.5 | $0.00006 | $0.00698 |
| Haiku 4.5 | $0.00003 | $0.00349 |
Grade A, and why
spec-driven-development 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 16d 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 — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Spec-Driven Development
Overview
Write the implementation spec before writing code. The spec is the shared source of truth between the engineer, the command flow, and the reviewers. Code without a spec is guessing.
Tool discipline (phase-locked): spec authoring is a read + spec-artifact phase. Write only the spec artifacts (
docs/specs/<date>-<slug>.mdand its.jsonsidecar) — never source or test code. Code starts at Phase 3, after the approval gate; a source edit here is a scope violation.
Supplied spec/plan (adoption, not authoring): when the engineer hands in a complete spec or plan as the input (e.g.
docs/specs/…mdordocs/plans/…mdalready on disk),implement's Phase 0.7 adopts it as the source of truth. In that case this skill validates the supplied artifact against the schema and reconciles it against the current code (seeprior-work-check's existing-plan reconciliation) rather than re-authoring to a fresh path — never overwrite or version-bump the engineer's input. Seeimplement/SKILL.mdPhase 0.7.
When To Use
- New endpoints, handlers, routes, or views; database changes or migrations
- Multi-file work or breaking changes
- Any task where approval should happen before coding, or likely to outlast a short focused session
When NOT To Use
- Typo fixes, one-line config updates with no behavior impact, or small bug fixes that clearly stay within quick-fix scope →
fix
Modes
- Standard (default). The steps below: ambiguity gate, the spec sections, the JSON sidecar, honest
security_impact, prior-work check. - Extended spec (opt-in). Adds EARS/ANT requirements with
lint-ears.sh, the INVEST+C 16-item score, a cited Constitution Check, and a delta against a per-area baseline. Turn it on when the engineer asks for it, or when the Phase 2 rigor score lands at MAX — then add the extended sections before the Phase 2.5 gate. Record the mode in the spec header (Spec mode: extended). See Extended Spec Mode below.
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.
- 16d ago Changed · -196 lines 296c5ffb3af0
- 1mo ago Changed · -143 lines 3d75d6e9ea1e
- 2mo ago First seen · 470 lines · 31 tokens per session scan A 6e2835a66c9a
spec-driven-development is a skill published in the GitHub repository moberghr/mtk-agent-toolkit (9 stars, last pushed 8d ago), licensed MIT. It adds 31 tokens to every session and 3,488 once invoked, about $0.0001 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.
Other skills, from other repositories
local-ai-agents
Build local-first AI agents that run entirely on a developer workstation with Microsoft Foundry Local and Qwen function-calling models. Covers Small Language Models (SLMs), the OpenAI-compatible local endpoint, sandboxed local tools, local RAG with Chroma, local MCP servers, hybrid cloud/local routing, and the…
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
next-cache-components-adoption
Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…
chat-pet-sprite-creation
Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…
insight-error-page
Write or audit an insight-kind error page for the Next.js dev overlay. Use when creating a new errors/ .mdx page, auditing an existing one, or checking that a page matches the framework fix cards. Covers page structure, title alignment, FixCard cards with Copy prompt button, code snippets, terminology verification…