tv-eval

tv-eval is a skill for Claude Code, Codex from specula-org/SysMoBench. It costs 69 tokens per session (190 once invoked), scanned A, original, Apache-2.0.

A method for testing how closely a TLA+ specification models a real system. TLA+ is a language for describing and checking how systems behave over time.

In plain words
What is it for?
For instrumenting a real system, comparing its behavior with a TLA+ model, running TLC model checks, and interpreting transition-validation scores.
Why use it?
It produces action-by-action pass rates with explanations, making the accuracy of an AI-generated specification easier to assess.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit For instrumenting a real system, comparing its behavior with a TLA+ model, running TLC model checks, and interpreting transition-validation scores.

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Install with agentmods
npx agentmods add skills/specula-org/sysmobench/tv-eval
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 specula-org/SysMoBench --skill tv-eval
Clone the repo
git clone --depth 1 https://github.com/specula-org/SysMoBench

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 tv-eval

README.md
[![agentmods](https://agentmods.dev/badge/skills/specula-org/sysmobench/tv-eval/github.svg)](https://agentmods.dev/skills/specula-org/sysmobench/tv-eval)
Your own site
<a href="https://agentmods.dev/skills/specula-org/sysmobench/tv-eval"><img src="https://agentmods.dev/badge/skills/specula-org/sysmobench/tv-eval/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 tv-eval

Your own site · 80×15
<a href="https://agentmods.dev/skills/specula-org/sysmobench/tv-eval"><img src="https://agentmods.dev/badge/skills/specula-org/sysmobench/tv-eval.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 190 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 $0.00069 $0.00190
Opus 5.5 $0.00028 $0.00076
Sonnet 5.5 $0.00014 $0.00038
Haiku 4.5 $0.00007 $0.00019

Measured 2mo ago against content hash fc3515f72cbc, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

tv-eval 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 2mo ago.

The scan reads SKILL.md. This mod also ships 9 executable files (examples/etcd/ai_spec_1/make_windows.py, examples/etcd/ai_spec_1/run_tv.py, examples/etcd/ai_spec_2/make_windows.py, …), 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.

tla_eval/skills/tv-eval/SKILL.md · 16 lines

What it actually says

Read guide.md for the full workflow.

Reference docs:

  • references/canonical_window_format.md — the one true window file schema
  • references/tv_module_template.md — how to write TV_.tla
  • references/score_interpretation.md — how to explain pass rates

Worked examples:

  • examples/spin/ — simple case (spinlock), 1 aux variable
  • examples/etcd/ — complex case (etcd-raft), 4 aux variables, log abstraction
Files

What ships with it

55 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. 2mo ago First seen · 16 lines · 69 tokens per session scan A fc3515f72cbc

Subscribe to this mod's changes

tv-eval is a skill published in the GitHub repository specula-org/SysMoBench (26 stars, last pushed 18d ago), licensed Apache-2.0. It adds 69 tokens to every session and 190 once invoked, about $0.0003 per session on Opus 5.5. 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.