---
id: improve.work-evolve
title: Work with External Agents
summary: Copy a benchmark-scoped task for your coding agent to implement and evaluate in your real application repository.
kind: task
product_area: improve
status: stable
updated: 2026-10-30
canonical: /docs/improve/external-agents
---

# Work with External Agents

External Agents gives your coding agent a concrete improvement task grounded in the selected Benchmark Version. The agent works in your real repository; Teammately supplies the applicable Cases, Policies, Rubrics and recorded results.

## Prerequisites

- A selectable Benchmark Version.
- Access to the application repository and authorization for the intended changes.
- A coding agent connected through the setup supplied with the task.
- An optional reference Run that genuinely represents the application starting point.

## Steps

1. Open **Harness improvement → External Agents**.
2. Select the Benchmark Version. Changing it clears local criterion and reference-Run selections.
3. Focus on the whole Benchmark or choose up to 20 approved and applicable Policy and Rubric Versions.
4. Optionally select one individual reference Run. No Run is silently selected.
5. Choose the allowed improvement direction: supported practices, prompt only, model only, the same model family, or model configuration only.
6. Copy the task, including setup instructions when needed, into your coding-agent conversation.
7. Have the agent inspect the actual repository, retrieve the pinned criteria and Run context, implement the change and evaluate it.
8. Inspect resulting Runs through ordinary Benchmark Evaluations.

The copied task includes the Project Agent Brief when present. Credentials do not belong in that text.

## Execution choices

A Teammately Harness and source upload are optional. Customer-executed responses are the default path for the agent's real application. Managed Harness execution requires a deliberate choice.

The product data MCP supplies read-only context, instructions, results and comparisons. The CLI owns local files and submission operations. The documentation MCP only retrieves these manuals.

Start with [CLI authentication](/docs/cli/authentication) and [product MCP setup](/docs/cli/mcp), then follow [external output submission](/docs/cli/external-outputs) or the optional [managed Harness workflow](/docs/cli/managed-harness).

## Object and state changes

The composer keeps selections locally and copies text. It creates no hosted agent Session, transcript, durable handoff object, automatic code adoption or Harness activation. Later submitted responses or managed execution create their own ordinary Run records.

## Success criteria

- The task preserves the intended Benchmark Version and criteria.
- A selected reference Run is checked against actual code.
- Implementation and comparison use actual pre-change and post-change behavior.
- Accepted responses and candidate identity remain attributable.

## Common failure modes

- Stopping after tool setup or context retrieval.
- Assuming a Harness upload is mandatory.
- Treating copied text as an executed Session.
- Using a reference Run from unrelated code.
- Claiming private agent work before returned artifacts or results exist.
## Related reference pages

{% related-card-grid title="Related reference pages" %}
- [Harness Improvement](/docs/improve)
- [Import External Evaluation Outputs](/docs/benchmark-evaluations/output-mapping)
- [Evaluation Results](/docs/benchmark-evaluations/results)
- [Project Context](/docs/agent-setup/project-context)
{% /related-card-grid %}

## Related troubleshooting pages

{% related-card-grid title="Related troubleshooting pages" %}
- [Output mapping troubleshooting](/docs/troubleshooting/output-mapping)
- [Permissions troubleshooting](/docs/troubleshooting/permissions)
{% /related-card-grid %}