R12.8: No unbounded collection growth

Short answer: Caches and registries specify TTL or LRU eviction. A cache with no limit grows for the life of the process.

Group: Memory and resource leaks. Status: stable. Generated from the rule definitions; do not edit by hand.

Playground: https://brevio.pro/tools/agent-guard-playground?rule=R12.8

What it catches

No unbounded collection growth: caches and registries specify TTL or LRU eviction.

Why

A cache with no limit grows for the life of the process.

A bad example

const cache = new Map();

A good example

const cache = new LRU({ max: 500, ttl: 60_000 });

How it is checked

Nothing yet. No scanner and no slice card checks it: it is a standing rule for authors and reviewers.

How to silence it

A person can silence one finding with brevio-core: ignore R12.8 -- reason on the line or the line above. Without the reason it does not count. An agent cannot silence it: the agent hook and the MCP tools never honour the comment, and a pull request that adds one is reported until a reviewer allows it. Fixing the code is still the better answer.

To change what the rule flags, edit its definition in dev_rules.py or code_rules/__init__.py. That is a code change and is reviewed like one.

R12.1 Event listener teardown
R12.2 Timer lifecycle cleanup
R12.3 Stream disposal hygiene
R12.4 WebSocket cleanup
Every rule