#Telemetry

A3S Code exposes runtime evidence through events, traces, verification reports, and result metadata.

#Result metadata

let result = session.send("Run release checks", None).await?;

println!("{}", result.usage.prompt_tokens);
println!("{}", result.usage.completion_tokens);
println!("{}", result.usage.total_tokens);
println!("{}", result.tool_calls_count);
println!("{:?}", result.verification_summary().status);
println!("{}", result.verification_summary_text());

const result = await session.send('Run release checks');

console.log(result.promptTokens);
console.log(result.completionTokens);
console.log(result.totalTokens);
console.log(result.toolCallsCount);
console.log(result.verificationStatus);
console.log(result.verificationSummaryText);

result = session.send('Run release checks')

print(result.prompt_tokens)
print(result.completion_tokens)
print(result.total_tokens)
print(result.tool_calls_count)
print(result.verification_status)
print(result.verification_summary_text)

result, err := session.Run(ctx, "Run release checks")
if err != nil {
	return err
}

fmt.Println(result.Usage.PromptTokens)
fmt.Println(result.Usage.CompletionTokens)
fmt.Println(result.Usage.TotalTokens)
fmt.Println(result.ToolCallsCount)
fmt.Println(result.VerificationSummary.Status)
fmt.Println(result.VerificationSummaryText)

#Traces and verification

let trace = session.trace_events();
let reports = session.verification_reports();
let summary = session.verification_summary();
let text = session.verification_summary_text();

const trace = session.traceEvents();
const reports = session.verificationReports();
const summary = session.verificationSummary();
const text = session.verificationSummaryText();

trace = session.trace_events()
reports = session.verification_reports()
summary = session.verification_summary()
text = session.verification_summary_text()

trace, traceErr := session.TraceEvents(ctx)
reports, reportsErr := session.VerificationReports(ctx)
summary, summaryErr := session.VerificationSummary(ctx)
text, textErr := session.VerificationSummaryText(ctx)

The Go methods cross the native bridge and therefore return an error; Rust, Node.js, and Python expose these in-process observation getters synchronously.

#Streaming events

Streaming returns versioned AgentEvent envelopes. version, type, payload, and optional metadata are the stable lossless fields; text, tool names, tool output, errors, token totals, and verification summaries are convenience projections. Unknown future type values and their payloads remain available to hosts.

#OpenTelemetry export

Rust hosts can export spans over OTLP by enabling the telemetry Cargo feature of a3s-code-core (included in the server and full profiles). The exporter lives in core/src/telemetry_otel.rs:

use a3s_code_core::telemetry_otel::TelemetryConfig;

let guard = TelemetryConfig::new("http://localhost:4317")
    .with_service_name("my-agent")
    .init()?;

// ... run sessions ...

guard.shutdown();

The default transport is gRPC; with_otlp_http() switches to OTLP/HTTP. Exports are bounded so an unreachable collector does not hold a coding turn or process shutdown. The Node.js, Python, and Go SDK crates do not declare a telemetry feature, so no published package includes the exporter; OTLP export is available only to Rust embedders. The opentelemetry entry returned by sdkCapabilities() is an advanced, host-owned capability that states this Core feature requirement.

#Logging

For product telemetry, prefer structured trace events and verification reports over scraping console output.