CaptureMode

CaptureMode is an opt-in, zero-configuration toggle that transparently enables deeper data collection across the entire agent execution pipeline — LLM conversations, tool I/O, memory operations, and delegation chains — without requiring any changes to your agents, tasks, or tools.

Capture levels

Level	What is captured	Trace size
OFF (default)	Prompts, tool arguments and results, timing, token counts	Minimal
STANDARD	Everything in OFF plus: full LLM message history per iteration, memory operation counts	Moderate
FULL	Everything in STANDARD plus: auto-export to ./traces/, enriched tool I/O with parsed JSON arguments	Larger

CaptureMode.OFF has zero performance impact beyond the base trace infrastructure that is always active. CaptureMode is orthogonal to verbose (logging) and traceExporter (export destination); all three can be combined independently.

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Activating CaptureMode

There are three ways to activate CaptureMode. They are resolved in the following order — the first match wins:

1. Programmatic (highest priority)

Ensemble ensemble = Ensemble.builder()
    .agent(researcher)
    .agent(writer)
    .task(researchTask)
    .task(writeTask)
    .captureMode(CaptureMode.FULL)
    .build();

EnsembleOutput output = ensemble.run();

// Export trace manually if needed
output.getTrace().toJson(Path.of("run-trace.json"));

2. JVM system property (zero code change)

java -Dagentensemble.captureMode=FULL -jar my-agent-app.jar

This activates FULL capture on every run without modifying application code. Useful for debugging in staging or investigating a specific production incident.

3. Environment variable (zero code change)

AGENTENSEMBLE_CAPTURE_MODE=STANDARD java -jar my-agent-app.jar

Useful for containerised deployments where you want to toggle capture without rebuilding the image.

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What STANDARD captures

Full LLM message history per iteration

At STANDARD, every LlmInteraction records the complete message list that was sent to the LLM for that iteration. This is available via LlmInteraction.getMessages() as a List<CapturedMessage>.

ExecutionTrace trace = output.getTrace();
TaskTrace taskTrace = trace.getTaskTraces().get(0);

for (LlmInteraction interaction : taskTrace.getLlmInteractions()) {
    System.out.println("Iteration " + interaction.getIterationIndex());
    for (CapturedMessage msg : interaction.getMessages()) {
        System.out.printf("  [%s] %s%n", msg.getRole(),
            msg.getContent() != null ? msg.getContent().substring(0, Math.min(80, msg.getContent().length())) : "(tool calls)");
    }
}

CapturedMessage fields:

Field	Populated for	Description
role	All messages	"system", "user", "assistant", or "tool"
content	system, user, assistant (final answer), tool	The text content
toolCalls	assistant (tool call request)	List of {name, arguments} maps
toolName	tool (result)	Name of the tool that produced the result

This enables replay of the exact conversation the LLM had, step by step.

Memory operation counts wired

At OFF, MemoryOperationCounts on TaskMetrics always has zero values because the counters are never incremented. At STANDARD, a MemoryOperationListener is wired into MemoryContext so that every STM write, LTM store, LTM retrieval, and entity lookup is counted:

TaskMetrics metrics = taskOutput.getMetrics();
MemoryOperationCounts memOps = metrics.getMemoryOperations();
System.out.println("STM writes:       " + memOps.getShortTermEntriesWritten());
System.out.println("LTM stores:       " + memOps.getLongTermStores());
System.out.println("LTM retrievals:   " + memOps.getLongTermRetrievals());
System.out.println("Entity lookups:   " + memOps.getEntityLookups());
System.out.println("Memory time:      " + metrics.getMemoryRetrievalTime());

Memory operations are only populated when memory is actually configured on the ensemble.

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What FULL adds

Auto-export to ./traces/

When captureMode == FULL and no explicit traceExporter has been registered, a JsonTraceExporter writing to ./traces/ is automatically activated. Each run writes a file named traces/{ensembleId}.json.

This is equivalent to:

Ensemble.builder()
    .captureMode(CaptureMode.FULL)
    .traceExporter(new JsonTraceExporter(Path.of("./traces/")))
    .build();

You can provide an explicit traceExporter to write to a different location and still benefit from the rest of FULL capture:

Ensemble.builder()
    .captureMode(CaptureMode.FULL)
    .traceExporter(new JsonTraceExporter(Path.of("/var/log/agents/traces/")))
    .build();

Enriched tool I/O

At FULL, each ToolCallTrace includes a parsedInput field — the tool’s JSON arguments parsed into a Map<String, Object>:

for (LlmInteraction interaction : taskTrace.getLlmInteractions()) {
    for (ToolCallTrace toolCall : interaction.getToolCalls()) {
        System.out.println("Tool: " + toolCall.getToolName());
        System.out.println("Arguments (raw): " + toolCall.getArguments());
        if (toolCall.getParsedInput() != null) {
            System.out.println("Arguments (parsed): " + toolCall.getParsedInput());
        }
    }
}

parsedInput is null at OFF and STANDARD. At FULL, it is null only when the arguments string cannot be parsed as a JSON object (e.g., malformed input from the LLM).

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CaptureMode and the trace schema

The ExecutionTrace carries a captureMode field so trace consumers can determine what depth of data to expect without inspecting individual interactions:

ExecutionTrace trace = output.getTrace();
System.out.println("Schema version: " + trace.getSchemaVersion()); // "1.1"
System.out.println("Capture mode:   " + trace.getCaptureMode());   // OFF / STANDARD / FULL

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Performance notes

Mode	Overhead vs base trace
OFF	None — same as not having CaptureMode at all
STANDARD	Memory proportional to conversation length (one CapturedMessage per message per iteration). For agents with many tool calls, this can be significant.
FULL	STANDARD overhead plus JSON parsing of every tool argument string (fast, but non-zero for very high throughput scenarios).

Document trade-offs in your team runbook when enabling STANDARD or FULL in production.

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Example: debugging a run without code changes

You have a deployed application and want to inspect what the LLM was sending and receiving during a specific run:

# Start the app with FULL capture (auto-exports to ./traces/)
java -Dagentensemble.captureMode=FULL -jar my-agent-app.jar

After the run completes, open traces/{run-id}.json in any JSON viewer. The trace contains:

• The complete message history the LLM saw in each iteration
• Every tool call with its input (raw and parsed) and output
• Token counts and latency per LLM call
• Memory operation counts if memory is configured

No redeployment required.