P·01
Foundation
ReAct
Reason → act → observe → repeat. The base pattern. An LLM interleaves natural-language reasoning with tool calls; each observation feeds the next reasoning step.
Patterns
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The pattern library. Twelve shapes the loop can take.
Every major lab has converged on the same handful. Picking the wrong one is the most common reason production agents fail.
P·02
Foundation
Plan · Execute · Verify
Draft a plan up front, execute each step, verify the result against the goal. Separates strategy from tactics and gives a natural checkpoint before shipping.
P·03
Pattern
Reflection
The agent critiques its own output before moving on. A second pass catches obvious mistakes, but self-grading is weaker than an independent check.
P·04
Pattern
Evaluator–Optimizer
Two roles. A generator produces; a separate evaluator scores against fixed criteria and returns specific fixes. Cycle two to four times.
P·05
Pattern
Retry Loop
Re-run a step until it succeeds or a limit hits. Cheap and effective against transient failures — network hiccups, rate limits, non-deterministic parses.
P·06
Pattern
Ralph Loop
Run the same prompt on repeat, a fresh context each pass, letting every iteration nudge the work forward. Crude and surprisingly effective — state lives in the artifacts, not the chat.
P·07
Advanced
Multi-Agent Supervisor
A controller dispatches work to specialist workers running in parallel, then merges results. Powerful, expensive, coordination-heavy.
P·08
Advanced
Debate
Multiple agents with different priors argue; a judge synthesizes. Reduces confidently-wrong single-agent outputs on high-stakes calls.
P·09
Advanced
Best-of-N
Generate several candidates in parallel — different seeds, prompts, or angles — and let a judge pick the winner. Trades tokens for quality when one attempt won't do.
P·10
Production
Circuit Breaker
Trip after N consecutive failures. Stop hammering a broken tool or spinning on an unsatisfiable goal. Cool off, then decide to retry.
P·11
Production
Bounded Execution
Hard caps: max iterations, token budget, wallclock, dollar spend. Any breach ends the loop with a partial result rather than a runaway.
P·12
Production
Human-in-the-Loop
Pause and request human sign-off on irreversible or ambiguous steps. The escape hatch that makes autonomy safe to ship.