@agentskit/observability — for agents

#Install

npm install @agentskit/observability

#Primary exports

#Loggers / tracers

• consoleLogger(config?) — local dev logging.
• langsmith(config) — LangSmith observer.
• opentelemetry(config) — OTel observer.
• createTraceTracker({ onSpanStart, onSpanEnd }) — low-level span lifecycle.

#Sinks (batch HTTP exporters)

• datadogSink(config) — Datadog Logs intake.
• axiomSink(config) — Axiom dataset ingest.
• newRelicSink(config) — New Relic Log API.

#Guards + counters

• costGuard(options) — dollar ceiling per run.
• multiTenantCostGuard(options) — per-tenant cost cap with shared bookkeeping.
• createAdvancedCostGuard({ budgets, caps, mode, disableRuntime, alertSinks }) — production-grade guard with warn / reject / kill modes, rolling window caps (perMinute / perDay / perMonth / custom), 50/80/100 % threshold alerts, linear forecast alerts, and pluggable sinks.
• consoleAlertSink(), webhookAlertSink({ url, headers }), throttle(sink, windowMs) — built-in alert sinks.
• chargebackReport(samples, { groupBy, from, to }) + chargebackReportToCsv(report) — pure cost-attribution exporter for finance / per-tenant invoicing.
• priceFor, computeCost, DEFAULT_PRICES.
• approximateCounter, countTokens, countTokensDetailed, createProviderCounter.

#PII redaction

• wrapObserverWithRedaction(observer, { rules, mode?, vault?, allowedRoles? }) — redact (or tokenize via @agentskit/core/security) string content fields in the AgentEvent stream (llm:end.content, tool:start.args, tool:end.result, agent:delegate:end.result, error.message) before they hit the underlying sink. Numeric / structural fields pass through unchanged so dashboards stay correct.

#Local trace viewer

• createFileTraceSink(dir), buildTraceReport, renderTraceViewerHtml. See Trace viewer.

#Devtools server

• createDevtoolsServer, toSseFrame. See Devtools server.
• createTopologyGraph — live multi-agent topology graph for the devtools UI.
• createControlSurface — production pause / step / replay control surface.

#SLO

• sloObserver(targets?), DEFAULT_SLO_TARGETS — emit SLO breach events from latency / error / cost windows.

#Signed audit log

• createSignedAuditLog, createInMemoryAuditStore. Hash-chain + HMAC. See Audit log.
• appendPiiAuditEvents(log, { actor, action, hits, subjectId?, reason? }) — append one signed entry per PII redaction hit to an existing SignedAuditLog. action is pii:redact, pii:reveal, or pii:reveal-denied; each payload records rule id, counts, and match offset/length only (no raw spans), for tamper-evident audit evidence alongside the hash chain.

#Minimal example

import { consoleLogger, costGuard } from '@agentskit/observability'
import { createRuntime } from '@agentskit/runtime'

const runtime = createRuntime({
  adapter,
  observers: [consoleLogger(), costGuard({ maxUsd: 0.5 })],
})

#Related

• @agentskit/observability-langfuse — Langfuse logger backend.
• @agentskit/eval
• @agentskit/runtime
• @agentskit/core/security — vault / tokenization used by wrapObserverWithRedaction.

#Source

• npm: https://www.npmjs.com/package/@agentskit/observability
• repo: https://github.com/AgentsKit-io/agentskit/tree/main/packages/observability