Hermes Minimizer

A native Hermes Python plugin that adds simplest-complete-system guidance through PluginContext.register_system_prompt_section.

The plugin contributes static guidance. It does not intercept tools, edit conversation history, make network requests, add dependencies, or enforce outcomes.

Requirements

Hermes Agent 0.22.0 or newer
The native register_system_prompt_section plugin API

Older or incompatible Hermes versions fail plugin registration with an upgrade message. There is no monkeypatch fallback.

Install

hermes plugins install nosliwhtes/hermes-minimizer --enable

Start a new Hermes session or process after enabling. Existing persisted prompts can retain the section bytes with which they were created.

Verify

hermes plugins doctor hermes-minimizer --ci
hermes plugins list --enabled --plain

Doctor exercises Hermes' real manifest discovery, import, and registration contracts. The test suite additionally verifies native rendering and actual system-prompt assembly.

Disable or remove

hermes plugins disable hermes-minimizer
# Start a new Hermes process/session to remove the guidance from new prompts.

hermes plugins remove hermes-minimizer

Disabling is config-only in a running process. A prompt already persisted for a session may retain its frozen plugin section.

Upgrade and compatibility

hermes plugins update hermes-minimizer

Version 0.1.0 is tested against Hermes source commit e06df9c2eae6901f4c88f464e0ae6e753c0428b8. Compatibility is capability-based as well as version-gated: registration requires the native prompt-section method and fails visibly if it is absent.

Limits

Guidance influences model behavior but does not guarantee simplicity, correctness, safety, or test coverage.
It is not a sandbox, authorization layer, policy enforcement engine, or test runner.
System, user, and repository instructions remain higher priority.
Static guidance is deterministic, but model responses are not.
Changes take effect at Hermes' normal plugin/session lifecycle boundaries, not retroactively inside persisted prompts.

Development

Use the official Hermes source and lockfile as the test environment:

git clone https://github.com/NousResearch/hermes-agent.git ../hermes-agent
git -C ../hermes-agent checkout e06df9c2eae6901f4c88f464e0ae6e753c0428b8
uv sync --project ../hermes-agent --locked --python 3.14 --group dev

HERMES_SOURCE="$(cd ../hermes-agent && pwd)" \
  uv run --project ../hermes-agent pytest tests -q
uv run --project ../hermes-agent hermes plugins doctor . --ci
uv run --project ../hermes-agent hermes plugins validate .

See CONTRIBUTING.md for the change contract and THIRD_PARTY_NOTICES.md for provenance.

hermes-minimizer

README