Agent loops

Skill — Agent Loops

When this skill activates

Any task involving repeated automated execution, retry logic, autonomous pipelines, or self-repairing agent workflows. Also activates when implementing circuit breakers or provider-aware fallback chains.

Mandatory actions when this skill is active

Before implementation

1. Define the loop's termination condition explicitly. No infinite loops without escape.
2. Set a maximum iteration count (default: 10 for code changes, 50 for data processing).
3. Identify the checkpoint mechanism — how will state be preserved between iterations?

Loop Patterns

Sequential Pipeline:

Task 1 -> Task 2 -> Task 3 -> ... -> Complete

• Each task must succeed before the next starts
• On failure: log, checkpoint state, halt with context for resumption
• Use when: tasks have strict ordering dependencies

Circuit Breaker Pattern:

Attempt -> Success? -> Continue
            | No
         Failure count++
            |
         Count >= threshold?
            | Yes
         OPEN circuit -> wait -> half-open -> retry once

• Threshold: 3 consecutive failures opens the circuit
• Backoff: exponential (1s, 2s, 4s, 8s, max 60s)
• Half-open: after backoff, allow ONE request through
• If half-open succeeds: close circuit, resume normal operation
• If half-open fails: re-open circuit, double backoff

Provider-Aware Fallback Chain:

Primary Model -> Timeout/Error? -> Fallback Model -> Timeout/Error? -> Degrade gracefully

• Always try primary model first (respects cost-aware-routing tier)
• On timeout (>30s) or error: switch to fallback
• Fallback models: same tier or one tier down
• Log every fallback with reason in AUDIT
• Never silently degrade — always inform user of fallback

Self-Repair Loop:

Execute -> Verify -> Pass? -> Done
                    | No
                 Diagnose -> Fix -> Re-verify (max 3 attempts)

• After 3 failed self-repair attempts: STOP and escalate to user
• Each repair attempt must be DIFFERENT from the previous
• Log each diagnosis and attempted fix

During implementation

• Every loop MUST have: max iterations, checkpoint logic, escalation path
• Never catch-and-swallow errors in loop bodies — always log with context
• Track iteration count in AUDIT entries
• Use SHARED_TASK_NOTES.md for cross-iteration context (see cross-iteration-bridge.md)

After implementation

• Verify the loop terminates under all test conditions
• Verify the circuit breaker opens and closes correctly
• Confirm escalation path works (simulate max-retries-exceeded)

Self-check before task completion

• Did I define explicit termination conditions for every loop?
• Did I set maximum iteration limits (no unbounded loops)?
• Did I implement checkpoint/state persistence between iterations?
• Did I verify the escalation path works when max retries are exceeded?