roster-spec-formal

roster-spec-formal is a skill for Claude Code, Codex from mathiasbourgoin/roster. It costs 42 tokens per session (4,769 once invoked), scanned A, original, MIT.

A formal specification step that extends a software specification with a machine-readable model in Rocq or Quint.

In plain words
What is it for?
Use it after the specification phase when you need a Rocq (.v) or Quint (.qnt) artifact for further verification.
Why use it?
It gives critical behavior a precise form that can be checked with formal methods instead of relying only on informal descriptions.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; names the AskUserQuestion tool; mentions Claude Code.

Good fit Use it after the specification phase when you need a Rocq (.v) or Quint (.qnt) artifact for further verification.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mathiasbourgoin/roster/roster-spec-formal
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.

Any agent
npx skills add mathiasbourgoin/roster --skill roster-spec-formal
Clone the repo
git clone --depth 1 https://github.com/mathiasbourgoin/roster

Made for: Claude Code, Codex.

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 roster-spec-formal

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/mathiasbourgoin/roster/roster-spec-formal"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/roster-spec-formal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,769 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 $0.00042 $0.04769
Opus 5 $0.00021 $0.02384
Sonnet 5 $0.00008 $0.00954
Haiku 4.5 $0.00004 $0.00477

Measured 4d ago against content hash 124d7e077f21, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

roster-spec-formal 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 4d 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.

.agents/skills/roster-spec-formal/SKILL.md · 387 lines

How it starts

The opening of the file, as written. The whole thing — 387 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Roster Preamble

This preamble is injected into every roster skill that declares preamble: true. It encodes the non-negotiable principles that govern all skill runs.


Principles

Completeness

Do not defer tests, documentation, or robustness in the name of speed. A short-term shortcut is rarely faster than a complete solution. "We'll add tests in a follow-up" is not an acceptable decision — it is explicit debt, or it is not a decision at all.

Search Before Build

Before creating anything, verify what already exists:

  1. Local (current repo, harness, KB)
  2. Roster (index.json, roster GitHub)
  3. Web (if webfetch available)

A false positive (checking for something that didn't exist) costs seconds. A false negative (building something that already existed) costs hours and creates debt.

Anti-Sycophancy

Do not validate a direction if you have a grounded objection. Do not say "good idea" before verifying it is a good idea. If you spot a problem, say so — clearly, factually, without softening. State your recommendation, explain why, mention what context you might be missing, and ask.

User Sovereignty

When you and a sub-agent both agree to change the user's direction: → present the recommendation → explain why you both think it is better → state what context you might be missing → ask

Never act unilaterally in this case. The decision belongs to the user.

Escalation

If you are blocked, the situation is ambiguous, or the action exceeds the declared scope: → escalate to the human — do not deviate from scope, do not guess

Asking Questions

When you need to ask the user something, use your runtime's interactive input tool if one is available — do not ask via plain text output.

Known runtime tool names:

Runtime Tool name
Claude Code AskUserQuestion
Copilot CLI ask_user
Codex request_user_input
OpenCode question

Rules:

  • One question at a time — never bundle multiple questions into one message
  • Prefer multiple-choice options over open-ended when the answer space is predictable
  • If no interactive tool is available, output a clearly marked plain-text question and wait for the user's reply before proceeding

Read the full file on GitHub · 387 lines

Files

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.

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. 4d ago Changed · +61 lines 124d7e077f21
  2. 11d ago First seen · 326 lines · 42 tokens per session scan A 5e36359c2d88

Subscribe to this mod's changes

roster-spec-formal is a skill published in the GitHub repository mathiasbourgoin/roster (2 stars, last pushed 4d ago), licensed MIT. It adds 42 tokens to every session and 4,769 once invoked, about $0.0002 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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