A skill that checks an execution through three stages: mechanical checks, meaning and goal checks, and optional agreement between multiple models. Mechanical checks include linting, builds, and tests.

Use it to evaluate an execution session, its artifact, or both, with checks for correctness, completeness, alignment, and drift.

It catches basic failures first, then checks whether the result actually meets the requested goal.

evaluate — Skill by Q00

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/q00/ouroboros/evaluate

Any agent

npx skills add Q00/ouroboros --skill evaluate

Clone the repo

git clone --depth 1 https://github.com/Q00/ouroboros

Made for: Claude Code, Codex.

Per session 9 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,884 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.

Model	Per session	Once invoked
Fable 5	$0.00009	$0.01884
Opus 5	$0.00005	$0.00942
Sonnet 5	$0.00002	$0.00377
Haiku 4.5	$0.00001	$0.00188

Measured 2d ago against content hash f3a8d30d5cf0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

evaluate 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.

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/evaluate/SKILL.md · 170 lines

How it starts

The opening of the file, as written. The whole thing — 170 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/ouroboros:evaluate

Evaluate an execution session using the three-stage verification pipeline.

Usage

/ouroboros:evaluate <session_id> [artifact]

Trigger keywords: "evaluate this", "3-stage check"

How It Works

The evaluation pipeline runs three progressive stages:

Stage 1: Mechanical Verification ($0 cost)
- Lint checks, build validation, test execution
- Static analysis, coverage measurement
- Fails fast if mechanical checks don't pass
Stage 2: Semantic Evaluation (Standard tier)
- AC compliance assessment
- Goal alignment scoring
- Drift measurement
- Reasoning explanation
Stage 3: Multi-Model Consensus (Frontier tier, optional)
- Multiple models vote on approval
- Only triggered by uncertainty or manual request
- Majority ratio determines outcome

Instructions

When the user invokes this skill:

Load MCP Tools (Required first)

The Ouroboros MCP tools are often registered as deferred tools that must be explicitly loaded before use. You MUST perform this step before proceeding.

Use the active runtime's tool-discovery capability to find and load the evaluate MCP tools:
```
tool discovery query: "+ouroboros evaluate"
```
The tool will typically be named mcp__plugin_ouroboros_ouroboros__ouroboros_start_evaluate (with a plugin prefix). After runtime tool discovery returns, the tool becomes callable.
If the tool is callable — already exposed, or loaded by discovery — proceed with the MCP-based evaluation below. An empty discovery result for an already-exposed tool is expected, not a failure. Skip to the Fallback section only if the tool is genuinely absent (no Ouroboros MCP server).

IMPORTANT: Do NOT skip this step. Do NOT assume MCP tools are unavailable just because they don't appear in your immediate tool list. They are almost always available as deferred tools that need to be loaded first.

CRITICAL — deferred-schema guard (prevents "Invalid tool parameters"): This skill can call ouroboros_start_evaluate after a fresh turn. A deferred tool's schema loaded on one turn is NOT guaranteed to still be loaded on the next. If you call it while its schema is not loaded in the current turn, the runtime rejects the call with "Invalid tool parameters" before it reaches the server. Therefore: immediately before EVERY ouroboros_start_evaluate call in this skill, re-run tool discovery query: "+ouroboros evaluate" (idempotent — a no-op when already loaded). If the load returns no matching tool (and the tool is not already callable — an empty load for an already-exposed tool is an expected no-op, not absence), switch to the documented fallback instead of retrying the failing call.

Read the full file on GitHub · 170 lines

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.

2d ago First seen · 170 lines · 9 tokens per session scan A f3a8d30d5cf0

Subscribe to this mod's changes

evaluate is a skill published in the GitHub repository Q00/ouroboros (5,747 stars, last pushed today), licensed MIT. It adds 9 tokens to every session and 1,884 once invoked, about $0.0000 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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