---
id: concepts.lemon-code
title: Lemon Code
summary: Develop a Harness through a conversation connected to its draft, relevant context, and proposed file changes.
kind: concept
product_area: introduction
status: stable
updated: 2026-11-06
canonical: /docs/concepts/lemon-code
---

# Lemon Code

Work with Lemon Code on the code, context, and instructions around your model. The conversation stays connected to the Harness draft, so you can investigate behavior and develop changes where the implementation lives.

## Definition

Open a Harness under **Assets → Harnesses**. Describe the behavior you want to understand or change and bring the relevant context into the conversation. Lemon Code can examine the implementation and propose file changes.

Inspect the proposed diff, refine the approach through discussion, and decide which changes to apply to the draft. Publishing preserves an exact saved Harness Version for subsequent execution.

## Decision checkpoint

| Your question | Work with | Useful result |
| --- | --- | --- |
| Why does this Harness behave this way? | Lemon Code and the current source | An explanation connected to the implementation |
| How should this intervention be implemented? | Lemon Code and selected context | A proposed change for review |
| Does the saved candidate behave better? | Trialground | Recorded responses and rubric results |
| Which competing approach should we investigate? | Lemon Goal | Candidates tested against a benchmark objective |

## Develop a focused change

Explain the observed problem and the desired outcome. Attach the relevant policy, reference material, or benchmark context when it helps establish what the change should achieve.

Read the proposal as an implementation decision. Check the affected files, the intended behavior, and the constraints your team needs to preserve. Continue the conversation when the approach needs refinement.

## Take the candidate into evaluation

Apply the changes you choose and publish the draft as a saved Version. Use a debug run to try supplied inputs, then run the candidate against the intended Benchmark Version in Trialground.

Inspect gains and regressions against the same criteria that motivated the edit. Your engineers decide which ideas to integrate into the production system.

{% example-demo title="Resolve conflicting-document answers" %}
A benchmark exposes unsupported blends of current and superseded documents. In the Harness editor, ask Lemon Code to examine source selection and propose an intervention. Review the file diff, publish the candidate, and compare its grounding and uncertainty results in Trialground.
{% /example-demo %}

## Related workflows

{% related-card-grid title="Develop and assess a Harness" %}
- [Harnesses](/docs/assets/harnesses)
- [Run a Benchmark Evaluation](/docs/benchmark-evaluations/run-evaluation)
- [Start a Lemon Goal Session](/docs/improve/start-improvement-session)
{% /related-card-grid %}

## Related reference pages

{% related-card-grid title="Supply useful context" %}
- [Working with Lemon](/docs/concepts/lemon)
- [Reference Materials](/docs/agent-setup/reference-materials)
- [Rubrics and Policies](/docs/correctness-governance/policies-and-rubrics)
{% /related-card-grid %}