spec-kickoff

spec-kickoff is a skill for Claude Code from bks-lab/open-bridge. It costs 292 tokens per session (2,306 once invoked), scanned A, original, MIT.

A guided planning process for defining a software build before substantial implementation begins. It produces a self-contained SPEC.md file with requirements and an end-to-end verification step.

In plain words
What is it for?
It helps you interview stakeholders, write requirements in a consistent format, define the build environment and verifier, and hand a checked specification to implementation.
Why use it?
It reduces the risk of building against an unclear goal by asking focused questions and agreeing on how the result will be checked.

Skill for Claude Code

Written for Claude Code: PreToolUse hook event. Also seen: mentions CLAUDE.md; mentions subagents; names the AskUserQuestion tool.

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/bks-lab/open-bridge/spec-kickoff
Any agent
npx skills add bks-lab/open-bridge --skill spec-kickoff
Clone the repo
git clone --depth 1 https://github.com/bks-lab/open-bridge

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 spec-kickoff

README.md
[![agentmods](https://agentmods.dev/badge/skills/bks-lab/open-bridge/spec-kickoff.svg)](https://agentmods.dev/skills/bks-lab/open-bridge/spec-kickoff)
Your own site
<a href="https://agentmods.dev/skills/bks-lab/open-bridge/spec-kickoff"><img src="https://agentmods.dev/badge/skills/bks-lab/open-bridge/spec-kickoff.svg" alt="Measured on agentmods" height="20"></a>
Per session 292 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,306 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 5.1 $0.00292 $0.02306
Opus 5 $0.00146 $0.01153
Sonnet 5 $0.00058 $0.00461
Haiku 4.5 $0.00029 $0.00231

Measured 6d ago against content hash 8f5248c4d049, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

spec-kickoff 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 6d 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.

skills/spec-kickoff/SKILL.md · 150 lines

How it starts

The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec-Kickoff

A phased, checkpointed kickoff for starting a new build the right way — Andrej Karpathy's three layers (spec → verifier → environment), expressed through Claude Code's own primitives. You produce one self-contained SPEC.md that ends in an end-to-end verification step, then hand off to the build.

This is not a new framework. It is spec-kit's discipline + Kiro's EARS/gates, expressed through Anthropic's native "interview → SPEC.md → verify-loop" pattern, wired into the environment the user already has. Conceptual depth, the verified Karpathy sources, and the EARS / ladder / gate cheat-sheets live in references/method.md. The artifact you fill is assets/SPEC.md. A one-page visual explainer for humans (open in a browser) ships at assets/spec-kickoff-explainer.html.

Talk to the user in their conversation language. Keep the interview sharp and short — a handful of load-bearing questions, not a survey. This skill is opt-in: when invoked the structure is wanted, but never let it become a ceremony tax.


Phase 0 — Frame & skip-check (≈30 seconds)

  1. Skip-gate first. If any of these holds, say so and do NOT run the kickoff:

    • you could describe the whole change in one sentence (Anthropic: skip the plan);
    • it's a quick fix (≲10 min, <3 files);
    • you're mid-build, not starting something new.

    → Point at the normal build flow. The method is for substantial new builds.

  2. Autonomy level (Karpathy's autonomy slider): tight / medium / wide — how much leash the build gets. Default tight; widen only as the verifier earns trust.

  3. Where the spec lives. Copy assets/SPEC.md to the task's home. On a Bridge instance that's work/tasks/<slug>/SPEC.md — fold it into the reflex-pause / task, don't create a parallel artifact.

Phase 1 — SPEC (Layer 1: the human owns the goal)

Run an interview — use AskUserQuestion for branching decisions. Cover, in order:

Read the full file on GitHub · 150 lines

Files

What ships with it

3 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. 6d ago First seen · 150 lines · 292 tokens per session scan A 8f5248c4d049

Subscribe to this mod's changes

spec-kickoff is a skill published in the GitHub repository bks-lab/open-bridge (8 stars, last pushed yesterday), licensed MIT. It adds 292 tokens to every session and 2,306 once invoked, about $0.0015 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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