# Rate Limiter Plugin
> Author: Mihai Criveti
> Version: 0.1.0
Applies fixed-window, in-memory rate limits by user, tenant, and tool.
## Hooks
- prompt_pre_fetch
- tool_pre_invoke
## Config
```yaml
config:
by_user: "60/m"
by_tenant: "600/m"
by_tool:
search: "10/m"
```
## Design
- Fixed-window counters tracked in-process using second/minute/hour buckets based on rate unit.
- Separate buckets per user, tenant, and tool; all must be within limits for a request to pass.
- Returns violations in `enforce` mode; includes remaining and reset hints in metadata.
## Limitations
- In-memory only; not shared across processes/hosts and resets on restart.
- Fixed windows are susceptible to burst-at-boundary effects; not a sliding window.
- No Redis/distributed backend in this implementation.
## TODOs
- Add Redis backend for distributed rate limiting.
- Support sliding window or token-bucket algorithms for smoother throttling.
- Add per-route/per-prompt overrides and dynamic config reload.
