metis-build-spec

metis-build-spec is a skill for Claude Code from gsaranti/pantheon. It costs 25 tokens per session (659 once invoked), scanned A, original, MIT.

A build-planning skill that turns project information into a final description and an ordered list of work items.

In plain words
What is it for?
It creates .metis/SYNTHESIS.md and .metis/BUILD.md, using reconciled documents, pending questions, or an explicitly supplied project prompt.
Why use it?
It gives the project a documented target and sequence of implementation tasks before coding begins.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: mentions subagents.

Runs only inside a plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else, and the catalogue could not identify which plugin ships it.

Good fit It creates .metis/SYNTHESIS.md and .metis/BUILD.md, using reconciled documents, pending questions, or an explicitly supplied project prompt.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

There is no command for this one: it runs only inside a plugin, and the catalogue could not identify which plugin ships it. The source is linked below.

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 metis-build-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/gsaranti/pantheon/metis-build-spec/github.svg)](https://agentmods.dev/skills/gsaranti/pantheon/metis-build-spec)
Your own site
<a href="https://agentmods.dev/skills/gsaranti/pantheon/metis-build-spec"><img src="https://agentmods.dev/badge/skills/gsaranti/pantheon/metis-build-spec/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 metis-build-spec

Your own site · 80×15
<a href="https://agentmods.dev/skills/gsaranti/pantheon/metis-build-spec"><img src="https://agentmods.dev/badge/skills/gsaranti/pantheon/metis-build-spec.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 659 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.
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 $0.00025 $0.00659
Opus 5 $0.00013 $0.00329
Sonnet 5 $0.00005 $0.00132
Haiku 4.5 $0.00003 $0.00066

Measured 10d ago against content hash 22135086bf73, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

metis-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 10d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (references/build-spec-preflight.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

plugins/metis/.claude-code/skills/metis-build-spec/SKILL.md · 54 lines

How it starts

The opening of the file, as written. The whole thing — 54 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/metis-build-spec

Produce the build's two standing files: .metis/SYNTHESIS.md in its final form (what is being built) and .metis/BUILD.md (the ordered backlog of items that build it).

Preflight

Run references/build-spec-preflight.sh before drafting. It exits non-zero if .metis/BUILD.md already exists (surface the error, suggest the user delete the file manually if a fresh rewrite is intended, and stop). Otherwise it reports DOCS_PRESENT, RECONCILE_DONE, and WALK_PENDING.

Input shape

Determined from the preflight + the trailing prompt:

  • Docs-first readyDOCS_PRESENT=yes, RECONCILE_DONE=yes, WALK_PENDING=no. Synthesize from the reconciled corpus.
  • Reconcile or walk pendingRECONCILE_DONE=no or WALK_PENDING=yes. Suggest the prerequisite command (/metis-reconcile or /metis-walk-open-items) and proceed only if the user explicitly insists.
  • No docsDOCS_PRESENT=no. The trailing prompt is required; if absent, stop and ask. If present, classify as prompt-seeded (fresh project) or existing-codebase (delta on top of code in the repo) based on what the prompt describes.

Load

  • For docs-first: .metis/SYNTHESIS.md, .metis/INDEX.md, and the source docs under docs/ at the cited passages.
  • For existing-codebase: code from the source tree, via metis-code-explorer subagent dispatches.

Do not load

  • .metis/CONTRADICTIONS.md, .metis/QUESTIONS.md, .metis/RESOLVED.md.

Read first

references/writing-build-spec.md — read before drafting.

Write scope

Two files:

  • .metis/SYNTHESIS.md — rewritten to its final standing form. When it already exists (docs-first, from reconcile), Read it before the Write so the overwrite succeeds on the first attempt.
  • .metis/BUILD.md — created: the ordered backlog, every item under To build, Built empty.

Invocation prompt

Trailing prompt: see ${CLAUDE_PLUGIN_ROOT}/references/command-prompts.md.

Return

One message to the user:

Read the full file on GitHub · 54 lines

Files

What ships with it

2 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. 10d ago First seen · 54 lines · 25 tokens per session scan A 22135086bf73

Subscribe to this mod's changes

metis-build-spec is a skill published in the GitHub repository gsaranti/pantheon (3 stars, last pushed 18d ago), licensed MIT. It adds 25 tokens to every session and 659 once invoked, about $0.0001 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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