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Instructions define always-on agent behavior. They form the core of the agent’s system prompt.
Managed Deep Agents is in public beta and available on LangSmith Cloud in the US region only.
Put the instructions for your agent into instructions.md at the project root:
For the full project layout, see Project structure.

Add instructions

Create or modify instructions.md to define the agent’s role, behavior, constraints, and guidance for using its tools:
instructions.md
MDA inserts instructions into the agent’s system prompt on every run. The agent cannot modify these instructions at runtime.

Deployment

When you run mda deploy, MDA syncs instructions.md to the agent’s Context Hub. You can then edit the instructions in the LangSmith UI and have those changes apply to the agent. It is best to keep the instructions.md file in the repo as the source of truth for lasting changes, as later deployments sync the project copy again. For what syncs, what does not, and how to open the repo from a deployment, see Context Hub.

When to use instructions

For more information, see Project structure.