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Run npx -y cc-safety-net@latest install --hermes-agent. It writes a managed Python plugin into plugins/cc-safety-net/ inside the Hermes home directory and enables it with the hermes CLI. Then restart Hermes to load the plugin. The plugin fails closed, which means Hermes blocks the tool call when the analysis cannot finish. This integration runs on macOS and Linux only.

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Install CC Safety Net in Hermes Agent

1

Run the installer

2

Restart Hermes

Restart Hermes. Do the same after every update or uninstall.
3

Confirm the plugin is active

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What the Hermes Agent install changes

  • The installer writes two managed files, __init__.py and plugin.yaml, to <Hermes home>/plugins/cc-safety-net/.
  • It then runs hermes plugins enable cc-safety-net --no-allow-tool-override. Hermes loads a user plugin only when its config lists it as enabled.
The Hermes home is HERMES_HOME, or ~/.hermes when that is unset. When that directory’s active_profile file names a profile, the home is profiles/<name> inside it, the same profile the hermes CLI uses. When HERMES_HOME already points into a profiles directory, CC Safety Net uses it as written.

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What the Hermes Agent plugin checks

On each pre_tool_call event, the plugin sends the tool call to npx -y cc-safety-net hook --hermes-agent with a 30-second timeout. It checks the terminal, read_file, write_file, and patch tools, each in the directory Hermes would run it in.

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What happens when the Hermes Agent check fails

The plugin fails closed. When npx is missing, or the analysis cannot start, times out, exits non-zero, or returns unreadable output, the plugin blocks the tool call with an explicit message. When it cannot read the tool’s directory from Hermes, it blocks the call with:
For a terminal call, the message says session in place of file tool.

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Hermes Agent coverage limits

  • Other tools. Calls from any Hermes tool other than the four above get no decision.
  • Commands you type. A !command you type yourself does not raise pre_tool_call, so Hermes’ own command guard handles it. CC Safety Net sees only the tool calls the model makes.
  • A plugin Hermes never loads. If Hermes does not load the plugin, CC Safety Net blocks nothing. doctor reads the plugin files and the Hermes config but cannot ask a running Hermes, so restart Hermes and test again after a change.
  • Windows. The install writes the plugin to a POSIX path that Hermes on Windows does not read.

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Uninstall CC Safety Net from Hermes Agent

Uninstall runs hermes plugins disable cc-safety-net, then removes the plugin files. If the hermes CLI fails or is missing, it still removes the files and warns that the Hermes config may still list cc-safety-net. Restart Hermes afterward.

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Troubleshoot Hermes Agent

  • Install or uninstall refuses to touch a path. The plugin directory or a managed file is a symlink, is not a regular file or directory, or lacks the CC Safety Net managed header. Move or remove that path yourself and run the command again.
  • Invalid Hermes profile name "<profile>" in <root>/active_profile. The active_profile file names a profile that is not a valid Hermes profile id. Run hermes profile use <name> with a valid profile. Install and uninstall stop at this error, and doctor reports it on the Hermes Agent row.
Last modified on October 22, 2026