---
plan_id: "03-01"
status: complete
commits:
  - "657f308 feat(rate-limiter): convert ceiling to AtomicU32 + add set_ceiling()"
  - "39e28ec test(rate-limiter): add test_set_ceiling_updates_limit"
requirements_completed:
  - PARA-03
tests_passed: 16
tests_added: 1
---

# Summary 03-01: Rate Limiter Dynamic Ceiling

## What Changed

**File**: `crates/opendeviationbar-providers/src/binance/rate_limiter.rs`

1. `ceiling: u32` converted to `ceiling: AtomicU32` — safe for concurrent reads from `acquire()` and writes from `set_ceiling()`
2. `new()` and `new_with_ceiling()` constructors use `AtomicU32::new()`
3. `usable_budget()` reads ceiling via `.load(Ordering::Relaxed)`
4. New `pub fn set_ceiling(&self, new_ceiling: u32)` — atomic swap with tracing debug log
5. New test `test_set_ceiling_updates_limit` — verifies 3000 -> 4800 -> 3000 -> 0 transitions

## Verification

- `cargo check -p opendeviationbar-providers` passes
- All 16 rate_limiter tests pass (including CAS concurrency test and parallel fetch integration)
- Zero API changes to existing consumers — `new()`, `new_with_ceiling()`, `usable_budget()` signatures unchanged
