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 agentmods add skills/lab2a/metalworks/build-specnpx skills add Lab2A/metalworks --skill build-specgit clone --depth 1 https://github.com/Lab2A/metalworksWrote 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/lab2a/metalworks/build-spec)<a href="https://agentmods.dev/skills/lab2a/metalworks/build-spec"><img src="https://agentmods.dev/badge/skills/lab2a/metalworks/build-spec.svg" alt="Measured on agentmods" 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 | $0.00225 | $0.01519 |
| Opus 5 | $0.00112 | $0.00759 |
| Sonnet 5 | $0.00045 | $0.00304 |
| Haiku 4.5 | $0.00022 | $0.00152 |
Grade A, and why
build-spec 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 5d 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 — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Preamble (run first)
Before any other tool, run the preflight MCP tool (or metalworks preflight on
the CLI). If it reports setup issues or that an update is available, surface that
to the user in one line and help them resolve it (install the missing extra/key,
or pip install -U metalworks) before continuing. Skip only if the user has
already passed preflight this session.
Read the reference; never reverse-engineer the source. The moment you need to know how
metalworks behaves — provider/model resolution, which source/reader runs, config precedence,
an error you hit, or the async run loop — STOP and read docs/operating-metalworks.md
(bundled with this plugin) before opening any file under src/. It is the source of truth;
do not derive behavior from source. (Full docs: https://metalworks.lab2a.ai/docs.) For a
long-running run, poll status with the Monitor tool or a bounded loop — never a blind sleep.
You are turning one finished demand report into a build the user's OWN coding
agent will execute. metalworks researched and specced; it does not write the
product. The output is two things: a grounded BuildSpec and an on-disk harness
that carries the evidence forward so the downstream agent cannot drift from
validated demand.
Steps
-
Get the
report_id. If the user hasn't run a report yet, point them at/demand-reportfirst — the build spec needs a finished report to ground in. -
Generate the spec. On the CLI this is one command that also writes the harness:
metalworks build init <report_id> --dest ./build --surface auto --base <stack-hint>. Via MCP, call thebuild_spectool with thereport_id(optionallysurfaceandstack) to get theBuildSpecJSON without writing files. It needs a chat + embedding provider (Tier 2) — a configured key, or the keyless Claude Code login whenmetalworks[claude-code]is installed. Leave--surface auto(the default) to let the spec pick the surface and explain why; pin it (e.g.--surface cli) when the user already knows the build shape.
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.
- 5d ago First seen · 92 lines · 225 tokens per session scan A 991c1245310f
build-spec is a skill published in the GitHub repository Lab2A/metalworks (6 stars, last pushed 2mo ago), licensed MIT. It adds 225 tokens to every session and 1,519 once invoked, about $0.0011 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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