Harness

This docs was updated at: 2026-03-21

com.paragon.harness.Harness  ·  Class

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Cohesive builder that composes all harness features around any Interactable.

A Harness wires together self-correction, lifecycle hooks, progress logging, artifact storage, and run reporting in a single fluent API — without requiring changes to the underlying agent.

Example:

ArtifactStore store = FilesystemArtifactStore.create(Path.of("./artifacts"));
ProgressLog log = ProgressLog.create();
Interactable harnessedAgent = Harness.builder()
    .selfCorrection(SelfCorrectionConfig.builder().maxRetries(3).build())
    .hooks(HookRegistry.of(new LoggingHook(), new CostTrackingHook()))
    .artifactStore(store)
    .progressLog(log)
    .reportExporter(RunReportExporter.create(Path.of("./reports")))
    .wrap(myAgent);
AgentResult result = harnessedAgent.interact("Build the feature");

Since: 1.0

Methods

builder

public static @NonNull Builder builder()

Returns a new Harness builder.

Returns

a new builder

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wrap

public @NonNull Interactable wrap(@NonNull Interactable agent)

Wraps the given agent with all configured harness policies.

Parameters

Name	Description
agent	the agent to wrap

Returns

an Interactable that enforces all harness policies

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asStreaming

public com.paragon.agents.Interactable.@NonNull Streaming asStreaming()

Returns a streaming view backed by the delegate's streaming, with harness hooks applied.

Fires beforeRun before the stream starts and afterRun when onComplete or onError fires. Tool-level hooks are covered by the agent's own HookRegistry (wired in com.paragon.agents.AgentStream).

Returns

an com.paragon.agents.Interactable.Streaming backed by the delegate

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selfCorrection

public @NonNull Builder selfCorrection(@NonNull SelfCorrectionConfig config)

Enables self-correction with the given configuration.

Parameters

Name	Description
config	the self-correction config

Returns

this builder

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selfCorrection

public @NonNull Builder selfCorrection()

Enables self-correction with default settings (3 retries, retry on error).

Returns

this builder

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hooks

public @NonNull Builder hooks(@NonNull HookRegistry registry)

Sets the hook registry.

Parameters

Name	Description
registry	the hook registry

Returns

this builder

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addHook

public @NonNull Builder addHook(@NonNull AgentHook hook)

Adds a single hook to the registry.

Parameters

Name	Description
hook	the hook to add

Returns

this builder

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artifactStore

public @NonNull Builder artifactStore(@NonNull ArtifactStore store)

Attaches an artifact store and exposes it as tools to the agent.

Parameters

Name	Description
store	the artifact store

Returns

this builder

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progressLog

public @NonNull Builder progressLog(@NonNull ProgressLog log)

Attaches a progress log and exposes it as tools to the agent.

Parameters

Name	Description
log	the progress log

Returns

this builder

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reportExporter

public @NonNull Builder reportExporter(@NonNull RunReportExporter exporter)

Attaches a run report exporter so each run is automatically recorded.

Parameters

Name	Description
exporter	the exporter

Returns

this builder

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wrap

public @NonNull Interactable wrap(@NonNull Interactable agent)

Wraps the given agent immediately and returns the harnessed interactable.

Parameters

Name	Description
agent	the agent to wrap

Returns

the harnessed interactable

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build

public @NonNull Harness build()

Builds the Harness (without wrapping an agent yet).