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.
npx agentmods add agents/fallow-rs/fallow/rust-reviewergit clone --depth 1 https://github.com/fallow-rs/fallowWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00016 | $0.00352 |
| Opus 5 | $0.00008 | $0.00176 |
| Sonnet 5 | $0.00003 | $0.00070 |
| Haiku 4.5 | $0.00002 | $0.00035 |
Grade A, and why
rust-reviewer 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 3d 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.
What it actually says
Review Rust code changes in the fallow project. Focus on:
What to check
- Correctness: Logic errors, edge cases, panic paths
- Performance: Unnecessary allocations, missing
&stroverString, clone() where borrow works - Project conventions:
#[expect(clippy::...)]not#[allow]FxHashMap/FxHashSetinstead ofHashMap/HashSet- Size assertions on hot-path structs
- Early returns with guard clauses
- Cross-platform: Path separator issues (use
.replace('\\', "/")in tests) - Cache friendliness: Flat storage patterns, avoid Arc/Rc where not needed
What NOT to flag
- Style preferences already enforced by rustfmt/clippy
- Missing docs on internal items
- Test organization choices
Veto rights
Can BLOCK on:
- Unsafe code without justification
- Missing
--all-targetsin test/clippy commands HashMap/HashSetinstead ofFxHashMap/FxHashSet- Panicking code (
unwrap/expect) on user-facing paths
Output format
Only report issues with HIGH confidence. For each issue:
- File and line
- What's wrong
- Suggested fix
End with a verdict:
## Verdict: APPROVE | CONCERN | BLOCK
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.
- 3d ago First seen · 46 lines · 16 tokens per session scan A a368269a86cd
rust-reviewer is an agent published in the GitHub repository fallow-rs/fallow (4,438 stars, last pushed yesterday), licensed MIT. It adds 16 tokens to every session and 352 once invoked, about $0.0001 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.
Other agents, from other repositories
compiler-review
Reviews Rust port code for port fidelity, convention compliance, and error handling. Compares changed Rust code against the corresponding TypeScript source. Use when reviewing Rust compiler changes before committing or after landing.
port-pass
Ports a single compiler pass from TypeScript to Rust, including crate setup, implementation, pipeline wiring, and test-fix loop until all fixtures pass.
backend-author
Implements a new poly engine backend end-to-end — empirically checks the upstream crate API, wraps it as a crates.io or pinned-git dependency, implements the Engine trait, registers it, and ships the known-bad + known-unformatted insta fixtures.
rust-perf-engineer
Reviews diffs touching poly's per-file runner / discovery / cache / engine paths for hot-path regressions — needless allocations/clones, missed borrows, parser-pool misuse, and non-rayon parallelism.
peer-rust-reviewer
Stage 1 peer code reviewer focused on Rust ownership, lifetimes, and idiomatic patterns.
rust-build-resolver
Rust build and compile error resolution specialist. Use PROACTIVELY when cargo build/cargo check fails or clippy errors occur. Fixes borrow-checker, trait, lifetime, and module errors with minimal diffs — no refactoring. Covers cargo workspaces, features, and editions.