Proposition Checking

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 Failure Modes

• 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

For each paragraph, extract:

• The proposition being asserted.
• Whether it is legal, factual, procedural, evidential, or mixed.
• The citation or record reference offered in support.
• Any direct quotation.

Do not treat a string citation as support until the proposition it supposedly supports is identified.

2. Retrieve or read the source

Use supplied source text first:

• Case text, statute, regulation, pleading, exhibit, transcript, witness statement, expert report, or correspondence.
• Public sources or research tools only if available and approved.

If the source cannot be retrieved, classify the proposition as unverified, not unsupported.

For every source used, record the source type, URL or document identifier, access date, and pinpoint. Do not assess support from model memory.

Confidence Bands

• High: source text is available, pinpointed, and directly supports or contradicts the proposition.
• Medium: source text is available but the proposition depends on interpretation, context, admissibility, or legal characterization.
• Low: source unavailable, quote incomplete, conflicting sources, or needs_review / unverified_source_unavailable.

3. Compare proposition to source

Classify each proposition:

• supported - source directly supports the proposition.
• partially-supported - source supports part of it, but the draft overstates or omits a condition.
• unsupported - source does not support the proposition.
• contradicted - source cuts the other way.
• quote-inaccurate - direct quotation is materially wrong.
• unverified - source unavailable or insufficient.

For legal propositions, distinguish:

• Existence of authority.
• Accuracy of the holding.
• Applicability to the jurisdiction, court level, facts, and procedural posture.

For factual propositions, distinguish:

• The source says the fact.
• Whether admissibility, competence, hearsay, privilege, or procedural use appears to require lawyer review under the governing rules.
• The fact is disputed elsewhere in the supplied record.

4. Report with traceability

Output:

| Field | Meaning | |---|---| | paragraph | source paragraph or location | | proposition | claim being checked | | citation | authority or record cite | | status | support classification | | source_location | page, paragraph, Bates, section, exhibit, or other pinpoint | | source_excerpt | exact supporting or contradicting text | | problem | overstatement, mismatch, missing source, etc. | | suggested_fix | narrow, replace cite, add source, or remove |

Use short excerpts. The goal is fast lawyer verification, not a replacement brief.

5. Identify dependency risk

After checking individual propositions, summarize:

• Arguments that depend on unsupported propositions.
• Citations repeatedly misused for the same point.
• Facts contradicted by the record.
• Authorities that exist but are cited for the wrong doctrine.
• Unverified sources that need manual research.

Escalation

Stop and route to the responsible lawyer when a key proposition is contradicted, an authority appears fabricated, a quote is materially inaccurate, admissibility/privilege controls the answer, or the user asks for merits advice rather than source support.

Example

Check whether each cited authority in this draft actually supports the proposition it is cited for. Separate citation existence problems from misuse problems.

For a compact output pattern, see examples/output.md. For proposition types, support states, and argument dependency mapping, see references/proposition-checking-model.md.

Limitations

• A source may support a proposition legally only after jurisdiction-specific research.
• The skill cannot assess undisclosed record material.
• unverified is not a merits conclusion.
• Admissibility and evidential competence concerns should be flagged for lawyer review unless the user supplies the governing rule and enough context to apply it.
• Privileged or sealed materials require an approved processing environment.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: LegalQuants
• Source: LegalQuants/lq-skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.