Automatic Retries & Circuit Breakers

When your agent calls an external API and it fails, what happens? Most agent code either crashes, retries infinitely, or silently drops the request. All three are wrong.

Hexel Tool Gateway gives you production-grade reliability primitives out of the box:

Exponential Backoff with Jitter

Failed requests are retried with increasing delays (1s, 2s, 4s) plus random jitter to prevent thundering herd. Configurable per-tool: max_retries defaults to 3.

Circuit Breakers (3-State)

Each backend has an independent circuit breaker: - **Closed** (normal): requests pass through - **Open** (failing): requests are immediately rejected with a clear error — no wasted time waiting for timeouts - **Half-Open** (probing): a single request passes to check recovery

When Salesforce is down, your Gmail tool calls still work. One failing API never cascades.

Request Deduplication

Two layers of protection against double-sends: 1. **Idempotency keys** (24h TTL): if your agent retries with the same key, the gateway returns the cached result 2. **Content-hash dedup**: for non-side-effecting tools, identical inputs within a window return cached results

What this means for your agents:

Your agent asked to "send an email to alice@acme.com" and the network hiccuped mid-response? The gateway knows it already executed successfully and returns the cached result. No duplicate email. No confused customer.

Before: 60-100 lines of retry logic, timeout handling, and dedup guards per integration.

After: Zero lines. It's built into the execution layer.