The Repair Loop

Attempt 1 → LLM returns output
           → Boundary validates (schema + rules)
           → Fails: "tier is hot but score is 25"
           → Failure classified as INVARIANT_ERROR
           → Repair message generated from violation

Attempt 2 → LLM receives original prompt + repair context
           → Returns corrected output
           → Boundary validates again
           → All rules pass → ACCEPTED

const result = await contract.accept(async (attempt) => {
  // attempt.repairs is empty on first try
  // on retries, it contains targeted fix instructions
  const res = await openai.responses.create({
    model: "gpt-4.1",
    input: [
      "Score this lead",
      ...attempt.repairs,  // ← violations from prior failure
    ],
  });
  return res.output_text;
});

const contract = defineContract({
  schema,
  rules,
  retry: {
    maxAttempts: 3,              // default: 3
    backoff: "none",             // "none" | "linear" | "exponential"
    baseMs: 200,                 // delay base in milliseconds
  },
});

const contract = defineContract({
  schema,
  rules,
  repairs: {
    // Don't retry on refusal — the model won't change its mind
    REFUSAL: false,

    // Custom repair for validation errors
    VALIDATION_ERROR: (detail) => [
      {
        role: "user",
        content: `Your output didn't match the schema. Issues: ${detail.issues.join(", ")}. Please fix.`,
      },
    ],
  },
});

if (!result.ok) {
  // result.error.message — human-readable summary
  // result.error.attempts — every failed attempt with details
  console.log(`Failed after ${result.error.attempts.length} attempts`);
  console.log(result.error.message);
}