search-for-the-lemma

search-for-the-lemma is a cursor rule for Cursor from briangmilnes/APAS-VERUS. It costs 595 tokens per session, scanned A, original, MIT.

A search rule for finding existing Verus lemmas, which are proof functions that establish reusable mathematical facts about code. It uses a project search tool to look through the Verus standard library and related codebases.

In plain words
What is it for?
Use it before writing a new lemma or when a proof needs properties about sequences, sets, lengths, types, or related operations.
Why use it?
It reduces duplicate work and helps connect a failed proof to facts that may already be available.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Use it before writing a new lemma or when a proof needs properties about sequences, sets, lengths, types, or related operations.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/briangmilnes/apas-verus/search-for-the-lemma
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.

Clone the repo
git clone --depth 1 https://github.com/briangmilnes/APAS-VERUS

Made for: Cursor.

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 search-for-the-lemma

README.md
[![agentmods](https://agentmods.dev/badge/rules/briangmilnes/apas-verus/search-for-the-lemma/github.svg)](https://agentmods.dev/rules/briangmilnes/apas-verus/search-for-the-lemma)
Your own site
<a href="https://agentmods.dev/rules/briangmilnes/apas-verus/search-for-the-lemma"><img src="https://agentmods.dev/badge/rules/briangmilnes/apas-verus/search-for-the-lemma/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 search-for-the-lemma

Your own site · 80×15
<a href="https://agentmods.dev/rules/briangmilnes/apas-verus/search-for-the-lemma"><img src="https://agentmods.dev/badge/rules/briangmilnes/apas-verus/search-for-the-lemma.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 595 This file is loaded in full into every session.
When invoked 595 The same file — it is already loaded in full.
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 $0.00595 $0.00595
Opus 5 $0.00298 $0.00298
Sonnet 5 $0.00119 $0.00119
Haiku 4.5 $0.00060 $0.00060

Measured 8d ago against content hash d28a24040264, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

search-for-the-lemma 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 8d 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.

.cursor/rules/verus/search-for-the-lemma.mdc · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Search for the Lemma

When you think you need a lemma to complete a proof, you MUST search for it before assuming it doesn't exist or trying to write it yourself.

Use veracity-search (vstd is searched by default):

# Search for proof functions by name pattern
veracity-search 'proof fn .*len.*'

# Search for functions mentioning specific types
veracity-search 'fn _ types Seq'
veracity-search 'fn _ types Set'

# Search for functions with specific ensures clauses
veracity-search 'fn _ ensures .*no_duplicates.*'

# Combine type patterns
veracity-search 'fn _ types Seq.*Set'

# Search vstd + APAS-VERUS together
veracity-search -C ~/projects/APAS-VERUS 'proof fn lemma'

# Search with OR patterns
veracity-search 'fn \(to_set\|no_duplicates\)'
  • Before writing a new lemma
  • When a proof fails and you suspect a missing connection
  • When you need to relate two different views (e.g., Seq to Set)
  • When you need properties about sequence operations (take, push, subrange)

The Usual Suspects (search in order)

  1. veracity-search — vstd + APAS-VERUS function index
  2. vstd source~/projects/verus/source/vstd/
  3. Verus test suite~/projects/verus/source/rust_verify_test/tests/
  4. Verus examples~/projects/verus/examples/
  5. Verus community codebases~/projects/VerusCodebases/
  6. Verus Guidehttps://verus-lang.github.io/verus/guide/

Example Searches

Need Search Query
Sequence with no duplicates → set length 'proof fn _ ensures .*no_duplicates.*len.*'
Take + push equals take of next 'fn _ types Seq ensures .*take.*push.*'
Seq to Set conversions 'fn _ types Seq.*Set'
All lemmas about sets 'proof fn lemma.*set'

Only after searching and finding nothing relevant should you consider writing a new lemma.

Output Display

Always show the full output from veracity-search:

  • Always echo the output into your response text as a markdown code block - do not rely on the terminal widget which collapses output
  • Show all matches, not just summaries

Read the full file on GitHub · 78 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.

  1. 8d ago First seen · 78 lines · 595 tokens per session scan A d28a24040264

Subscribe to this mod's changes

search-for-the-lemma is a cursor rule published in the GitHub repository briangmilnes/APAS-VERUS (10 stars, last pushed 1mo ago), licensed MIT. It adds 595 tokens to every session, about $0.0030 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 2026-09-03.