Hermes ACP Editor Integration

Agent Client Protocol mode lets an ACP-compatible editor run Hermes as an editor-native coding agent over standard input and output. It is useful when file edits, terminal work, progress, and approval requests should appear inside the development environment.

Official documentation: https://hermes-agent.nousresearch.com/docs/user-guide/features/acp

Curated editor surface

ACP mode uses a focused toolset for reading, writing, patching, searching, terminal commands, and tracked processes. Messaging delivery and cron management are intentionally excluded because they do not fit the normal editor interaction model.

Hermes reuses the active profile's model and provider configuration. The ACP extra must be installed, and the editor launches the hermes acp server over stdio. Logs go to standard error so protocol traffic on standard output remains clean.

Setup checklist

Configure and test the Hermes provider first.
Install the ACP dependency through the documented package extra.
Run the version and health checks outside the editor.
Point the editor at the intended Hermes profile.
Keep stdout reserved for protocol messages.
Install browser support only if the editor workflow needs it.
Review session-only and permanent approval choices carefully.
Start with a disposable repository and low-risk edit.

Approval behavior

Editor approval choices map to Hermes safety semantics. A session allowance should expire with the process; a permanent allowance changes the durable command policy. The editor UI must show enough context for the user to distinguish them.

Pitfalls

Installing Hermes without the ACP extra and debugging the editor first.
Launching the wrong profile from an editor configuration.
Writing logs to stdout and corrupting JSON-RPC transport.
Adding messaging or scheduler expectations to the editor toolset.
Treating “allow always” as a harmless convenience.
Assuming optional browser binaries ship inside the Python package.

Verification steps

Run hermes acp --version and hermes acp --check.
Start the ACP server manually and confirm it remains healthy.
Connect a disposable editor workspace.
Ask for a read-only project summary.
Apply one small reversible edit and inspect the diff.
Exercise a session-only approval and confirm it does not persist after restart.
Run the project test and verify the result appears in the editor transcript.