Plugin Lifecycle¶

The plugin framework includes CLI tools to help you create, test, and deploy your plugins.

Development Flow¶

The plugin development workflow follows a straightforward workflow that gets you from idea to running plugin quickly.

graph LR

    A["template"]
    B(["$> bootstrap"])
    C(["$> build"])
    D(["$> serve"])

    subgraph dev
        A -.-> B
    end

    subgraph deploy
        C --> D
    end

    B --> C

    subgraph CF["Context Forge"]
        E["gateway"]
        D o--"MCP<br>&nbsp;&nbsp;<small>tools/call <i>hook</i></small>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"--o E
    end

    style A stroke-dasharray: 3 3;

The process breaks down into these main steps:

Bootstrap: Start with a plugin template and run the bootstrap command to set up your project structure
Build: Compile and package your plugin code
Serve: Launch a local development server to test your plugin
Connect: Your served plugin automatically integrates with Context Forge's gateway via MCP (Model Context Protocol), using tool calls over standardized hooks for seamless communication

This streamlined approach lets developers focus on building functionality rather than wrestling with configuration, while ensuring plugins work smoothly within the broader Context Forge ecosystem.

Bootstrap¶

Creating a new plugin for Context Forge only takes a few minutes!

Using the mcpplugins tool (installed with Context Forge),

mcpplugins bootstrap --destination your/plugin/dir

The interactive prompt you guide you to enter plugin metadata, and will boostrap a complete plugin project for you including everything you need to kick the tires writing your new plugin.

For a full list of options, check:

mcpplugins bootstrap --help

Tip

When prompted for the choosing the plugin type, select `external` to create standalone plugins (with their own lock files and dependency trees).
Select `native` if you want to create a plugin that embeds and gets loaded directly into the gateway environment.

The examples under the plugins directory in the gateway repository serve as a guide of how to develop and test native plugins.

The following instructions apply to external plugins. First, change directory to work with your newly bootstrapped plugin:

cd your/plugin/dir
cp .env.template .env

Configuration¶

There are two main configuration files for your project.

./resources
    /plugins/config.yaml # configuration for your plugin and the plugin loader
    /runtime/config.yaml # configuration for the plugin server runtime

Inspect those two files and get familiar with them. There are many options you can customize, depending on your use case.

Dependencies¶

Plugins are Python packages with dependencies managed by uv. Just like the gateway, you can add, lock, lint, and ensure that best practices are followed when creating your plugins. To install dependencies with dev packages (required for linting and testing), run:

make install-dev

Alternatively, you can also install it in editable mode:

make install-editable

Test¶

To run all unit tests for your plugins:

make test

Build¶

To build a container image (runtime) containing a standardized plugin server, run:

make build

Serve¶

To start the plugin server:

make start

By default, this will start a Streamable HTTP MCP server on http://localhost:8000/mcp.

You can run mcp inspector to check your new server (note, it requires npm):

npx @modelcontextprotocol/inspector

Gateway Integration¶

Let's assume you have boostrapped the following plugin (resources/plugins/config.yaml) with default runtime (resources/runtime/config.yaml) options:

plugins:
  - name: "MyFilter"
    kind: "myfilter.plugin.MyFilter"
    description: "A filter plugin"
    version: "0.1.0"
    author: "Frederico Araujo"
    hooks: ["prompt_pre_fetch", "prompt_post_fetch", "tool_pre_invoke", "tool_post_invoke"]
    tags: ["plugin"]
    mode: "enforce"  # enforce | permissive | disabled
    priority: 150
    conditions:
      # Apply to specific tools/servers
      - server_ids: []  # Apply to all servers
        tenant_ids: []  # Apply to all tenants
    config:
      # Plugin config dict passed to the plugin constructor

# Plugin directories to scan
plugin_dirs:
  - "myfilter"

# Global plugin settings
plugin_settings:
  parallel_execution_within_band: true
  plugin_timeout: 30
  fail_on_plugin_error: false
  enable_plugin_api: true
  plugin_health_check_interval: 60

To integrate this plugin with the gateway, all you need to do is copying the following configuration under the plugins list in the gateway's plugins/config.yaml file:

plugins:
  # External Filter Plugin
  - name: "MyFilter"
    kind: "external"
    priority: 10 # adjust the priority
    mcp:
      proto: STREAMABLEHTTP
      url: http://localhost:8000/mcp

Then, start the gateway:

make serve

Note

`PLUGINS_ENABLED=true` should be set in your gateway `.env` file.