Retry Mechanisms

Introduction

Agent steps fail — tools time out, JSON breaks, LLMs hallucinate. Retries turn a flaky world into a stable agent. Three patterns: simple retry, exponential back-off, retry-with-feedback.

Beginner analogy: the elevator button — pressing again often works; pressing harder doesn't.

Understanding the topic

Core concepts:

• Simple retry: try again same args.
• Back-off: wait 1s, 2s, 4s …
• Retry-with-feedback: tell the LLM what went wrong.
• Cap retries (3-5) and fail loudly.
• Idempotency keys prevent double-effects on retry.

Syntax reference

Visual workflow / architecture:

call ── fail ──► wait ── retry (with feedback)
                          │
                          ▼
                       success ─► continue
                          │
                          fail (max) ─► escalate

Real-world use

Every production agent retries tool calls; reflection loops are 'smart retries'.

Best practices

• Always cap retries.
• Pass error messages back to the LLM for self-correction.

Common mistakes

• Infinite retries on permanent failures.
• Retrying non-idempotent calls without keys (double charges!).

Hands-on exercise

Interview preparation — practice these questions:

• Q1. Three retry strategies.
• Q2. Why idempotency matters in retries.
• Q3. Scenario: your billing tool was retried and charged twice. Root cause?