Ax Go Agent Observability

---
name: "ax-go-agent-observability"
description: "Use when writing Go code with `github.com/ax-llm/ax/packages/go` for agent tracing, centralized and multi-tenant usage accounting, action logs, runtime diagnostics, replay, and production debugging."
version: "25.1.0"
---
# AxAgent Observability For Go

This skill helps an agent write Go code with the generated Ax package `github.com/ax-llm/ax/packages/go`. Use the generated package API, examples, and manifests; do not import TypeScript-only APIs unless you are editing the TypeScript package.

## When To Use

- Inspect agent traces, runtime envelopes, usage, or action logs.
- Register the process-wide usage observer and attribute model calls by tenant, user, request, run, or feature.
- Attach callbacks for model/tool activity and runtime progress.
- Debug agent loops through generated package state and examples.

## Package Facts

- Language: Go.
- Package: `github.com/ax-llm/ax/packages/go`.
- Package API docs: `API.md` and `axir-api.json`.
- Capability manifest: `axir-capabilities.json`.
- Runnable examples: `examples/`.
- Real network support: yes.
- Scripted no-key transport support: yes.
- Runtime profiles: `javascript-goja`.

## Core Pattern

```go
helper := ax.NewAgent("question:string -> answer:string", nil)
out := helper.Forward(llm, map[string]ax.Value{"question": "How should I proceed?"}, nil)
```

## Centralized Usage Observer

Use the process-wide usage observer for application accounting across many agents, API routes, tenants, and users. Keep per-agent usage accessors for inspecting one agent instance after a run.

```go
axllm.SetUsageObserver(func(event axllm.AxUsageEvent) {
    usageQueue.Enqueue(event)
})
// Later: axllm.SetUsageObserver(nil)
```

- The observer receives one normalized event for each completed chat or embedding call that reports provider usage. A fully consumed stream emits once; an unconsumed or cancelled stream may not emit.
- Events include the operation, AI/provider name, model, normalized tokens, streaming flag, optional usage context, and available session or remote request IDs.
- Attach `usageContext` in AI service options for stable application or environment defaults. Attach it in call or agent-forward option maps for tenant, user, request, run, and feature attribution.
- Per-call context overrides service defaults. Nested `attributes` are shallow-merged.
- The observer is process-wide, best-effort, and fail-open. Registering again replaces the previous observer. Clear it during test teardown or shutdown when appropriate.
- The observer runs on the request path. Production callbacks should synchronously enqueue into a bounded concurrent queue and return immediately, then persist or aggregate out of band. Use a shared durable pipeline across processes or serverless instances.
- Keep identifiers opaque and attributes low-cardinality. Do not attach prompts, responses, secrets, or other sensitive payloads.
- Calculate currency cost downstream against a versioned provider/model pricing table.
- Runnable provider example: `src/examples/go/generation/usage_observer.go`.

## Relevant API Surface

- AxAI: `axllm.NewAI`, `axllm.Typesafe`, `axllm.AxAITypesafeClient`, `context.Context`, `axllm.AxAIServiceAbortedError`, `axllm.GetSupportedAIModels`, `axllm.AxCredentialRequest`, `axllm.AxCredentialProvider`, `AxOwnedClientFactory.OwnedWorkerFactory`, `axllm.AxChatSession`, `axllm.AxChatStream`, `axllm.OpenAICompatibleClient`, `axllm.OpenAIResponsesClient`, `axllm.GoogleGeminiClient`, `axllm.AnthropicClient`, `axllm.AxUsageContext`, `axllm.AxUsageEvent`, `axllm.AxUsageObserver`, `axllm.SetUsageObserver`, `axllm.AxRuntimeHooks`, `axllm.AxRateLimitInfo`, `axllm.AxRateLimiter`, `axllm.AxTracer`, `axllm.AxMeter`, `axllm.AxGlobals`, `axllm.SetRateLimiter`, `axllm.SetTracer`, `axllm.SetMeter`, `axllm.AxBalancer`, `axllm.AxBalancerAdaptiveStrategy`, `axllm.AxBalancerStatsStore`, `axllm.AxInMemoryBalancerStatsStore`, `axllm.CreateBalancerRouteStats`, `axllm.UpdateBalancerRouteStats`, `axllm.SampleBalancerRouteHealth`, `axllm.MultiServiceRouter`, `axllm.ProviderRouter`
- Agents And RLM: `axllm.NewAgent`, `axllm.AxAgent`, `AxAgent.AddChildAgent`, `AxAgent.StreamingForward`
- Runtime Profiles: `axllm.ProcessCodeRuntime`, `axllm.RuntimeCapabilities`, `axllm.RuntimeEnvelope`, `javascript-goja`

## Guardrails

- Start from package examples for exact native syntax before inventing a new call shape.
- Use `provider-api` examples only when the user explicitly has provider credentials available.
- Use `no-key` examples for deterministic local checks and provider request mapping.
- Treat AxIR as the source of generated package truth: if package docs disagree with source code, update the compiler and regenerate packages.
- Do not copy repo-maintainer skills from `tools/*/skills/` into user packages.