Academy → Developer guideOfficial documentation · clear explanation

Context Engine Plugins

Context Engine الإضافات

Developer14 minutes3 questions2026-08-09
The idea in one minute

Start with meaning, then move to detail.

This lesson explains Context Engine Plugins as part of Hermes internals and extension points. You will learn what it does, when it matters, and the smallest safe test that proves it works.

If you are new

If you are new, do not memorize names. Focus on three questions: what problem does this solve, what access does it need, and how can you verify the result?

For hands-on use

For practice, inspect the first example, identify its effects, run it on test data, and compare the result with the source claim.

For specialists

For advanced readers, inspect How it works, Directory structure, The ContextEngine ABC, then verify failure modes and version compatibility.

What do you need first?

Know Python, Git, and basic project structure before changing code.

What will you know?

A clear outcome before you read.

  • Understand Context Engine Plugins without assumed prior knowledge.
  • Separate the source description from what still needs testing in your environment.
  • Read the first command and identify its inputs and outputs before copying it.
Lesson terms

Short definitions before the details.

Tool
A structured action the agent can call to read or change something.
Official page description

How to build a context engine plugin that replaces the built-in ContextCompressor

Topic map

What does the source say, and in what order?

  1. 01
    How it works

    Start here to understand the core idea or structure.

  2. 02
    Directory structure

    Read this after the foundation, then connect it to the previous step.

  3. 03
    The ContextEngine ABC

    Read this after the foundation, then connect it to the previous step.

  4. 04
    Class attributes your engine must maintain

    Read this after the foundation, then connect it to the previous step.

  5. 05
    Optional methods

    Read this after the foundation, then connect it to the previous step.

  6. 06
    Per-turn context selection and observation

    Read this after the foundation, then connect it to the previous step.

  7. 07
    When to use these hooks — and when NOT to

    Read this after the foundation, then connect it to the previous step.

  8. 08
    Engine tools

    Read this after the foundation, then connect it to the previous step.

  9. 09
    Registration

    Read this after the foundation, then connect it to the previous step.

  10. 10
    Via directory (recommended)

    Finish here to verify the result and special cases.

Examples from the official page

Copy only after you understand the effect.

# config.yaml context: engine: "compressor" # default built-in engine: "lcm" # activates a plugin engine named "lcm"
plugins/context_engine/lcm/ ├── __init__.py # exports the ContextEngine subclass ├── plugin.yaml # metadata (name, description, version) └── ... # any other modules your engine needs
### Class attributes your engine must maintain The agent reads these directly for display and logging:
Try it now

Read the first command and identify its inputs and outputs before copying it.

Match every command to your installed Hermes version, review the files and accounts it can reach, and use non-sensitive data for the first test. If this explanation differs from the source, the official source wins.

Knowledge check

Three decisions before completion.

1. What is the source of truth when “Context Engine Plugins” changes?
2. What is the best way to apply this lesson?
3. What should happen before a step can modify files or an external account?