Observability

Observability records the full execution path of an agent so you can understand its internal behavior, debug issues, analyze performance, and keep optimizing. VeADK’s built-in tracing captures each request — from receiving user input, through model inference, tool calls, memory and knowledge-base reads/writes, to producing a response — as structured span data, and reports it to Volcengine or third-party platforms through exporters. VeADK tracing follows the OpenTelemetry generative-AI semantic conventions, with field names aligned to standard span attributes. Trace data can therefore be imported directly into any OpenTelemetry-compatible system for analysis and visualization. Runtime logs use Python’s standard logging package. See Application logging for levels, formatting, and trace correlation.

Core concepts

span

A span is a traceable unit of execution that records a name, start/end times, attributes, and parent-child relationships. VeADK builds a tree of spans for each request, covering nodes such as agent runs, model calls, and tool executions, and annotates them per the generative-AI semantic conventions with attributes like gen_ai.operation.name and gen_ai.span.kind.

The tracer `OpentelemetryTracer`

OpentelemetryTracer is the unified tracing entry point. It holds a list of exporters, wires each one into the tracing pipeline on initialization, and automatically attaches an in-memory exporter for local retention and dumping.

exporter

An exporter sends span data to a specific backend platform. Each exporter targets one backend and can be used alone or combined. VeADK ships the following exporters:

Exporter	Class	Target platform	Docs
APMPlus	`APMPlusExporter`	Volcengine APMPlus, traces and metrics	APMPlus
Cozeloop	`CozeloopExporter`	Cozeloop, trace observation and evaluation	Cozeloop
TLS	`TLSExporter`	Volcengine TLS log service	TLS
In-memory	`InMemoryExporter`	In-process memory, local debugging and dumping	In-memory exporter

Attaching a tracer to an agent

Tracing is wired in through the tracers field of Agent. Construct an exporter for the target backend, hand it to OpentelemetryTracer, then attach the tracer to the agent:

import asyncio

from veadk import Agent, Runner
from veadk.memory.short_term_memory import ShortTermMemory
from veadk.tools.demo_tools import get_city_weather
from veadk.tracing.telemetry.exporters.apmplus_exporter import APMPlusExporter
from veadk.tracing.telemetry.opentelemetry_tracer import OpentelemetryTracer

exporters = [APMPlusExporter()]
tracer = OpentelemetryTracer(exporters=exporters)

agent = Agent(tools=[get_city_weather], tracers=[tracer])

runner = Runner(agent=agent, short_term_memory=ShortTermMemory())

asyncio.run(runner.run(messages="How is the weather in Beijing?", session_id="session_id_demo"))

A single tracer can hold multiple exporters, reporting the same spans to several platforms:

from veadk.tracing.telemetry.exporters.apmplus_exporter import APMPlusExporter
from veadk.tracing.telemetry.exporters.cozeloop_exporter import CozeloopExporter
from veadk.tracing.telemetry.exporters.tls_exporter import TLSExporter
from veadk.tracing.telemetry.opentelemetry_tracer import OpentelemetryTracer

tracer = OpentelemetryTracer(
    exporters=[APMPlusExporter(), CozeloopExporter(), TLSExporter()]
)

Tracer parameters

OpentelemetryTracer accepts the following fields:

Parameter	Type	Default	Description
`name`	`str`	`veadk_opentelemetry_tracer`	Tracer identifier, used for logging and naming dump files.
`exporters`	`list[BaseExporter]`	`[]`	List of exporters. `InMemoryExporter` may not be added explicitly, or validation fails; the in-memory exporter is attached automatically.
`apmplus_managed_externally`	`bool`	—	Read-only property. Whether a global `TracerProvider` already existed at initialization. When `True`, VeADK reuses the external provider instead of overriding it and automatically removes `APMPlusExporter`.

InMemoryExporter is managed automatically by OpentelemetryTracer and records every span. Do not add it to the exporters list manually, or initialization fails.

Reusing a preconfigured global TracerProvider

By default, OpentelemetryTracer creates and sets the global TracerProvider during initialization. If a global TracerProvider already exists at that point (for example, set by another library or the application itself), VeADK reuses it instead of overriding it. In this case VeADK automatically removes APMPlusExporter from the exporters list, because the existing provider is assumed to be responsible for APMPlus trace reporting. Other exporters (such as CozeloopExporter and TLSExporter) are still registered with that provider. The VeADK in-memory exporter is also attached as usual.

This behavior also applies when ENABLE_APMPLUS=true auto-creates the exporter: if a global TracerProvider already exists, the auto-created APMPlusExporter is also removed.

You can check the apmplus_managed_externally property to determine whether the tracer detected an external provider:

tracer = OpentelemetryTracer(exporters=[APMPlusExporter()])
if tracer.apmplus_managed_externally:
    # VeADK reused an existing global TracerProvider; APMPlusExporter was removed
    pass

Enabling exporters via environment variables

Besides constructing exporters explicitly, Agent attaches the matching exporter at runtime based on the following environment variables (enabled when set to true). If the agent provides no tracers, an OpentelemetryTracer is created automatically:

Environment variable	Exporter enabled
`ENABLE_APMPLUS`	`APMPlusExporter`
`ENABLE_COZELOOP`	`CozeloopExporter`
`ENABLE_TLS`	`TLSExporter`

When all three variables are false (the default), Agent creates no tracer. To trace in that case, construct an OpentelemetryTracer explicitly and pass it via tracers.

Content tracing

By default, spans record the input and output content of the agent, model, and tools. In scenarios involving sensitive data, you can disable content capture and keep only the non-content span structure and timing. This is controlled by OpenTelemetryConfig.trace_content.

Config	Environment variable	Type	Default	Description
`trace_content`	`OBSERVABILITY_OPENTELEMETRY_TRACE_CONTENT`	`bool`	`True`	Whether to write prompt, completion, and tool input/output content into spans. Set to `false` to keep only non-content trace information.

# Disable content capture
export OBSERVABILITY_OPENTELEMETRY_TRACE_CONTENT=false

Local dumping

The in-memory exporter built into OpentelemetryTracer retains spans by session_id. Call dump to export the current session’s spans to a local JSON file for offline analysis:

path = tracer.dump(user_id="user-1", session_id="session_id_demo")
print(f"trace written to {path}")

The exported JSON contains, for each span, its name, span_id, trace_id, start/end times, attributes, and parent span. See In-memory exporter for details.

Overview

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Core components

Extensions

Frontend

Security

Deployment

Observability

Core concepts

span

The tracer `OpentelemetryTracer`

exporter

Attaching a tracer to an agent

Tracer parameters

Reusing a preconfigured global TracerProvider

Enabling exporters via environment variables

Content tracing

Local dumping

​Core concepts

​span

​The tracer OpentelemetryTracer

​exporter

​Attaching a tracer to an agent

​Tracer parameters

​Reusing a preconfigured global TracerProvider

​Enabling exporters via environment variables

​Content tracing

​Local dumping

Core concepts

span

The tracer `OpentelemetryTracer`

exporter

Attaching a tracer to an agent

Tracer parameters

Reusing a preconfigured global TracerProvider

Enabling exporters via environment variables

Content tracing

Local dumping