Hermes Agent

Install the hooks

After installing Edge and Hermes:

kastra-edge login
kastra-edge install-hermes --dry-run
kastra-edge install-hermes

The installer targets $HERMES_HOME/config.yaml, defaulting to ~/.hermes/config.yaml, while preserving existing hooks. It wires pre_tool_call and post_tool_call.

Complete Hermes consent

Writing configuration is only half of setup. Hermes requires consent for each shell-hook event/command pair. Start Hermes interactively and complete its hook approval, then inspect:

hermes hooks list
hermes hooks doctor
kastra-edge doctor

A non-interactive gateway or scheduled run can skip an unapproved hook even when the configuration is present. Do not enable a blanket hook auto-accept setting just to hide this requirement.

Coverage and failure behavior

pre_tool_call is the blocking hook. post_tool_call is audit-only; Hermes ignores block directives on other events. Both native and MCP tool calls exposed by those hooks can be evaluated. Chat-model traffic requires a separate proxy integration.

The installer detects Hermes support for fail_closed and reports configuration drift. Older versions can ignore that setting; verify the version and doctor output instead of inferring protection from the YAML key.

Verify and remove

Test a harmless allow, deny, and approval with actual hook execution. Review Windows-specific limitations before rollout. Remove only the managed integration with kastra-edge uninstall-hermes when needed.