Gptme Plugin Development

Step-by-Step: Creating a Tool Plugin

1. Create pyproject.toml

[project]
name = "gptme-my-plugin"
version = "0.1.0"
description = "My custom gptme plugin"
requires-python = ">=3.10"
dependencies = [
    "gptme>=0.27.0",  # Required for ToolSpec, etc.
]

[project.optional-dependencies]
test = [
    "pytest>=8.0.0",
]

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

[tool.hatch.build.targets.wheel]
packages = ["src/gptme_my_plugin"]

2. Create Simple init.py

Keep it simple to avoid import issues:

# src/gptme_my_plugin/__init__.py
"""My gptme plugin description."""

__version__ = "0.1.0"

Important: Don't import hooks or complex gptme internals here - it can cause import errors in tests.

3. Create the Tool

# src/gptme_my_plugin/tools/__init__.py
"""My plugin tools."""

from gptme.tools.base import ToolSpec, ToolUse


def my_function(arg1: str, arg2: int = 10) -> str:
    """
    Do something useful.

    Args:
        arg1: Description of arg1
        arg2: Description of arg2 (default: 10)

    Returns:
        Result description
    """
    return f"Result: {arg1} x {arg2}"


def examples(tool_format):
    return f'''
### Example usage
User: Do the thing
Assistant: I'll use my_function.
{ToolUse("ipython", [], "my_function('test', 5)").to_output(tool_format)}
'''


tool = ToolSpec(
    name="my_plugin",
    desc="Short description for tool list",
    examples=examples,
    functions=[my_function],
)

__doc__ = tool.get_doc(__doc__)

4. Write Tests

# tests/test_my_plugin.py
"""Tests for my plugin."""

from gptme_my_plugin.tools import my_function


def test_my_function():
    """Test the main function."""
    result = my_function("hello", 3)
    assert "hello" in result
    assert "3" in result

5. Run Tests

# From plugin directory
cd plugins/my_plugin

# Using uv in workspace
uv run pytest tests/ -v

# Or install and test
uv pip install -e ".[test]"
uv run pytest tests/ -v

Adding Hooks

For lifecycle hooks (SESSION_START, TOOL_PRE_EXECUTE, etc.):

# src/gptme_my_plugin/hooks/__init__.py
from gptme.hooks import HookType, register_hook
from gptme.message import Message


def on_session_start(logdir, workspace, initial_msgs):
    """Hook called at session start."""
    yield Message("system", f"Plugin loaded in: {workspace}")


def register():
    """Register all hooks from this module."""
    register_hook(
        "my_plugin.session_start",
        HookType.SESSION_START,
        on_session_start,
        priority=0,
    )

Available Hook Types:

• SESSION_START, SESSION_END - Session lifecycle
• TOOL_PRE_EXECUTE, TOOL_POST_EXECUTE - Tool execution
• FILE_PRE_SAVE, FILE_POST_SAVE - File operations
• GENERATION_PRE, GENERATION_POST - LLM generation

Adding Commands

For custom /command handlers:

# src/gptme_my_plugin/commands/__init__.py
from gptme.commands import register_command, CommandContext
from gptme.message import Message


def my_command_handler(ctx: CommandContext):
    """Handle the /mycommand command."""
    args = ctx.full_args or "default"
    yield Message("system", f"Command executed with: {args}")


def register():
    register_command("mycommand", my_command_handler, aliases=["mc"])

Common Patterns

Optional Dependencies

For provider-specific features:

[project.optional-dependencies]
gemini = ["google-genai>=1.0.0"]
openai = ["openai>=1.0.0"]

Getting API Keys

def _get_api_key(env_var: str) -> str | None:
    """Get API key from gptme config first, then environment."""
    try:
        from gptme.config import get_config
        return get_config().get_env(env_var)
    except ImportError:
        import os
        return os.environ.get(env_var)

Fallback Imports

For standalone usage:

def _get_logs_dir():
    try:
        from gptme.dirs import get_logs_dir
        return get_logs_dir()
    except ImportError:
        from pathlib import Path
        return Path.home() / ".local" / "share" / "gptme" / "logs"

Testing with logs_dir Parameter

Make functions testable by adding optional parameters:

def my_stats(year: int | None = None, logs_dir: Path | None = None):
    if logs_dir is None:
        logs_dir = _get_logs_dir()
    # Use logs_dir...

Then in tests:

def test_my_stats(tmp_path):
    # Create test data in tmp_path
    result = my_stats(2025, logs_dir=tmp_path)
    assert result["year"] == 2025

Installation & Configuration

Configure plugins in gptme.toml at user-level (~/.config/gptme/config.toml) or project-level (gptme.toml in workspace root):

[plugins]
paths = ["~/.config/gptme/plugins", "/path/to/plugins"]
enabled = ["my_plugin"]  # Optional: limit which plugins load

See gptme Plugin Docs for full configuration details.

For Development

# Install in editable mode
uv pip install -e .

# Or in workspace
uv sync

Troubleshooting

Module Not Found in Tests

Problem: ModuleNotFoundError: No module named 'gptme_my_plugin'

Solution: Ensure you're running tests from the workspace environment:

cd /path/to/gptme-contrib
uv run pytest plugins/my_plugin/tests/ -v

Import Errors from init.py

Problem: Complex imports in __init__.py cause import failures

Solution: Keep __init__.py minimal:

# Bad
from gptme.plugins import hookimpl, PluginMetadata  # May fail

# Good
__version__ = "0.1.0"

Environment Mismatch

Problem: uv installs to different env than pytest runs from

Solution: Use uv run to ensure consistent environment:

uv run pytest tests/ -v

Examples in gptme-contrib

• wrapped: Analytics tool with tests
• imagen: Multi-provider image generation
• lsp: Language server integration
• consortium: Multi-model consensus
• example-hooks: Hook registration patterns

Related

• gptme Plugin Docs
• Custom Tools Guide
• Hooks System