ghost-param-sync

ghost-param-sync is a cursor rule for Cursor from briangmilnes/APAS-VERUS. It costs 308 tokens per session, scanned A, original, MIT.

A Verus rule for updating calls when a Rust trait method gains a Ghost parameter, which carries specification-only information.

In plain words
What is it for?
It helps synchronize trait method calls with current signatures, especially when verification functions are added.
Why use it?
It prevents argument-count and missing-method errors caused by callers using an outdated signature.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit It helps synchronize trait method calls with current signatures, especially when verification functions are added.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/briangmilnes/apas-verus/ghost-param-sync
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 ghost-param-sync

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

Your own site · 80×15
<a href="https://agentmods.dev/rules/briangmilnes/apas-verus/ghost-param-sync"><img src="https://agentmods.dev/badge/rules/briangmilnes/apas-verus/ghost-param-sync.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 308 This file is loaded in full into every session.
When invoked 308 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 $0.00308 $0.00308
Opus 5 $0.00154 $0.00154
Sonnet 5 $0.00062 $0.00062
Haiku 4.5 $0.00031 $0.00031

Measured 5d ago against content hash 327acf579e3f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

ghost-param-sync 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 5d 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/ghost-param-sync.mdc · 36 lines

What it actually says

Ghost Parameter Sync

When a trait method signature includes a Ghost(...) parameter (e.g., Ghost(spec_f): Ghost<spec_fn(T, T) -> T>) and a call site in a later chapter omits it, update the call site to pass the Ghost argument.

Detection

If compilation fails with "cannot find method" or argument-count mismatch on a trait method that exists, check whether the trait added a Ghost(...) parameter that the caller doesn't supply.

Fix

Add the missing Ghost(...) argument at the call site. Example:

// ❌ Old call (before Ghost was added to trait)
<ArraySeqMtEphS<i32> as ArraySeqMtEphBaseTrait<i32>>::scan(a, &|x, y| x + y, 0)

// ✅ Updated call (matches current trait signature)
<ArraySeqMtEphS<i32> as ArraySeqMtEphBaseTrait<i32>>::scan(
    a,
    &|x, y| x + y,
    Ghost(|x: i32, y: i32| -> i32 { (x + y) as i32 }),
    0,
)

Rule

  • The trait signature is the source of truth.
  • Never remove or skip the Ghost parameter in the trait to accommodate old callers.
  • Always update the caller to match the trait.
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. 5d ago First seen · 36 lines · 308 tokens per session scan A 327acf579e3f

Subscribe to this mod's changes

ghost-param-sync is a cursor rule published in the GitHub repository briangmilnes/APAS-VERUS (10 stars, last pushed 1mo ago), licensed MIT. It adds 308 tokens to every session, about $0.0015 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.