proposition-checking

proposition-checking is a skill for Claude Code, Codex from LegalQuants/lq-skills. It costs 55 tokens per session (1,334 once invoked), scanned A, original, Apache-2.0.

A checking method for testing whether statements in legal writing are actually supported by the cited cases, laws, exhibits, transcripts, emails, or pleadings. It checks support rather than predicting who will win a case.

In plain words
What is it for?
Use it to review briefs, motions, legal memoranda, advice notes, witness statements, and evidence summaries against their cited sources.
Why use it?
It helps catch citations that are irrelevant, overstated, misquoted, or otherwise do not support the proposition they follow. This reduces errors in drafts before lawyer review.

Skill for Claude CodeCodex

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

Good fit Use it to review briefs, motions, legal memoranda, advice notes, witness statements, and evidence summaries against their cited sources.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/legalquants/lq-skills/proposition-checking
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 LegalQuants/lq-skills --skill proposition-checking
Clone the repo
git clone --depth 1 https://github.com/LegalQuants/lq-skills

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 proposition-checking

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/legalquants/lq-skills/proposition-checking"><img src="https://agentmods.dev/badge/skills/legalquants/lq-skills/proposition-checking.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,334 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 $0.00055 $0.01334
Opus 5 $0.00028 $0.00667
Sonnet 5 $0.00011 $0.00267
Haiku 4.5 $0.00006 $0.00133

Measured 11d ago against content hash b50864876673, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

proposition-checking 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 11d 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/proposition-checking/SKILL.md · 144 lines

How it starts

The opening of the file, as written. The whole thing — 144 lines — stays where its author put it; the contents beside it link to each section on GitHub.

proposition-checking

When to Use

  • A brief, skeleton argument, motion, memo, advice note, or witness statement makes propositions tied to citations.
  • The user wants to know whether cited cases, statutes, exhibits, or witness evidence actually support the statement made.
  • A citation exists, but the concern is misuse rather than fabrication.
  • The user asks whether a quotation, paraphrase, or record reference is accurate.

This skill checks support. It does not predict who wins and does not replace legal judgment.

Audience and Work Shape

Audience: litigators, legal researchers, trainees, and paralegals checking draft arguments or evidence summaries for lawyer review.

Work shape: pattern-matched source checking with accretive judgment. The skill maps propositions to sources and grades support; it does not make the legal argument for the user.

  • Legal support, not legal advice: support classification is a verification aid, not a merits opinion.
  • Privilege/confidentiality: drafts, exhibits, transcripts, and advice notes may be privileged or confidential; use approved environments and mark source limitations.
  • Accountability: the responsible lawyer decides whether to keep, narrow, replace, or abandon the proposition.

Access Modes

This skill works in three modes:

  1. Live source mode - use browser, web search, MCP, API, or other configured access to retrieve authorities, statutes, rules, or public records.
  2. User-supplied source mode - use uploaded or pasted judgments, statutes, exhibits, pleadings, transcripts, correspondence, witness statements, or record bundles.
  3. No-source mode - extract propositions and citations, then prepare a verification queue. Do not classify support as supported, unsupported, or contradicted.

If the source cannot be retrieved or supplied, mark the proposition unverified-source-unavailable. Do not assess source support from model memory.

How It Works

1. Separate propositions from citations

Read the full file on GitHub · 144 lines

Files

What ships with it

5 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. 11d ago First seen · 144 lines · 55 tokens per session scan A b50864876673

Subscribe to this mod's changes

proposition-checking is a skill published in the GitHub repository LegalQuants/lq-skills (53 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 55 tokens to every session and 1,334 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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