spectre-prove

spectre-prove is a skill for Claude Code from joenandez/spectre. It costs 61 tokens per session (1,698 once invoked), scanned A, original, MIT.

An acceptance-proof workflow for checking completed work against its approved requirements using observable evidence such as screenshots, video, logs, or an HTML proof page.

In plain words
What is it for?
Use it after implementation to verify user journeys, collect evidence, review it, and publish an acceptance report.
Why use it?
It helps distinguish what the finished experience actually does from claims made by developers, tests, or reports.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Good fit Use it after implementation to verify user journeys, collect evidence, review it, and publish an acceptance report.

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Install with agentmods
npx agentmods add skills/joenandez/spectre/spectre-prove
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 joenandez/spectre --skill spectre-prove
Clone the repo
git clone --depth 1 https://github.com/joenandez/spectre

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 spectre-prove

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/joenandez/spectre/spectre-prove"><img src="https://agentmods.dev/badge/skills/joenandez/spectre/spectre-prove.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,698 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00061 $0.01698
Opus 5 $0.00030 $0.00849
Sonnet 5 $0.00012 $0.00340
Haiku 4.5 $0.00006 $0.00170

Measured 2d ago against content hash d1d31fbcb9ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

spectre-prove 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 2d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate-proof-html.mjs), 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/spectre-codex/skills/spectre-prove/SKILL.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

prove

Prove the completed experience against its approved contract. Reports, tests, assertions, and developer claims are leads; observable behavior and reviewed evidence decide.

Inputs

  • $ARGUMENTS - optional explicit feature name/root or descendant artifact, explicitly passed source-plan path, scope/UX/prototype/test-guide paths, journey hints, fresh inspected evidence to reuse, an authorized scope hash, and --orchestrated when a parent owns the next action.
  • Optional --profile focused, valid only with --orchestrated: use existing proof tools/scenarios only, run no tooling research or dependency-selection gate, and record unavailable proof capability as PARTIAL with limitation PROOF_TOOLING_UNAVAILABLE.
  • Resolve an explicit feature/root, descendant, or unambiguous thread artifact; otherwise derive a concise kebab name and proceed without a naming gate.
  • Reuse a managed FEATURE_ROOT only when explicit/current-thread evidence ties it to this work (physical directory wins; never branch/recency/lifecycle/scans); distinct work ignores ambient roots. Otherwise, including on collision, standalone MUST first load and follow Skill(spectre-feature-root) through DONE; orchestrated calls escalate. Keep writes beneath it and pass it unchanged.
  • Resolve acceptance truth in this order: current explicit user instruction; an explicitly passed source plan as an acceptance source; approved scope and UX/prototype; task acceptance criteria; test guide. Derivative execution evidence such as execution_state.md may focus proof but is not acceptance truth. Surface contradictions before proving against an invented interpretation.

This skill must work in a fresh session. Read canonical artifacts and live repository state instead of relying on prior conversation.

Each invocation is exactly one proof pass. Derive a candidate key from relevant product inputs, scope hash, and scenario/config definitions; record observed start/finish state excluding generated proof. If product state changes, mark affected rows PARTIAL with PROOF_STATE_CHANGED; never bind proof to a future candidate.

Read the full file on GitHub · 88 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. 2d ago Changed · +2 lines d1d31fbcb9ec
  2. 7d ago Changed ad3e76417761
  3. 12d ago First seen · 86 lines · 61 tokens per session scan A 23fe2f3072d9

Subscribe to this mod's changes

spectre-prove is a skill published in the GitHub repository joenandez/spectre (161 stars, last pushed 3d ago), licensed MIT. It adds 61 tokens to every session and 1,698 once invoked, about $0.0003 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 2026-08-30.

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