Guarantees (validator + quota)

Two production-grade safety primitives ship in @agentskit/runtime:

• Validator guard — wraps any regenerable agent output with a validator chain. Retry, block, or fall back on failure.
• Per-tool quota — hard caps on tool calls per run and per sliding window. Survives runaway loops.

Both are auditable and adapter-agnostic.

#Validator guard

import { createValidatorGuard, isJson, denyPattern } from '@agentskit/runtime'

const guard = createValidatorGuard({
  validators: [
    { name: 'json-shape', check: ({ output }) => isJson(output), onFail: 'retry', maxRetries: 2 },
    { name: 'no-pii', check: ({ output }) => denyPattern(/\b\d{3}-\d{2}-\d{4}\b/)({ output, attempt: 0 }), onFail: 'fallback' },
  ],
  fallback: '{"error":"redacted"}',
  audit: (event) => myAuditSink.write(event),
})

const result = await guard.run({
  regenerate: (repair) => runtime.run(prompt + (repair ?? '')).then(r => r.content),
})
// result.output, result.accepted, result.attempts, result.failures

Each validator gets its own retry budget, so a flaky JSON gate does not burn the budget that a strict PII gate also needs. Three failure actions:

Built-ins: isJson, denyPattern(re), lengthRange(min, max). Bring your own for RAG citation, eval LLM-judge, or domain rules.

Use cases: JSON-shape contracts, "never emit PII" final gate, "must cite a source from the corpus", SOX / HIPAA / fair-housing rails.

#Per-tool quota

import { createQuotaTracker, withQuotas, createRuntime } from '@agentskit/runtime'

const tracker = createQuotaTracker({
  env: process.env.NODE_ENV,
  quotas: {
    send_email: { perRun: 50, perWindow: { count: 500, windowMs: 60_000 } },
    drop_table: { dryRunRequiredIn: ['production'] },
  },
  onExceeded: (event) => alert.fire(event),
})

const runtime = createRuntime({
  adapter,
  tools: withQuotas([sendEmail, dropTable], tracker),
})

Two limits per tool:

• perRun — counter resets on every runtime.run().
• perWindow — sliding window shared across runs.

Plus dryRunRequiredIn: [...envTags] — destructive tools throw before execute runs in matching environments.

Quota breaches raise ToolError(AK_TOOL_QUOTA_EXCEEDED) and emit a tool:quota:exceeded event so observers and cost-guards can react.

#Related

• Runtime
• Cost guard
• Audit log
• Rate limiting