agentskills-langchain 0.2.2
LangChain integration for the Agent Skills format (https://agentskills.io)
License: MIT
Requires Python: <4.0,>=3.12

# agentskills-langchain

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> LangChain integration for the [Agent Skills SDK](../../README.md) - turn a skill registry into LangChain tools.

Generates a set of [LangChain](https://python.langchain.com/) `StructuredTool` instances from a `SkillRegistry`, ready to be passed to any LangChain agent.

## Installation

```bash
pip install agentskills-langchain
```

Requires Python 3.12+. Installs `agentskills-core` and `langchain-core` as dependencies.

## Usage

```python
from agentskills_core import SkillRegistry
from agentskills_fs import LocalFileSystemSkillProvider
from agentskills_langchain import get_tools, get_tools_usage_instructions

# Set up registry
provider = LocalFileSystemSkillProvider(Path("./skills"))
registry = SkillRegistry()
await registry.register("incident-response", provider)

# Build tools + system prompt
tools = get_tools(registry)
catalog = await registry.get_skills_catalog(format="xml")
instructions = get_tools_usage_instructions()
system_prompt = f"{catalog}\n\n{instructions}"
```

Pass `tools` to your LangChain agent and inject `system_prompt` into the system message. The catalog tells the agent *what* skills exist; the usage instructions tell it *how* to use the tools.

## Generated Tools

| Tool | Parameters | Description |
| --- | --- | --- |
| `get_skill_metadata` | `skill_id` | Get structured metadata (name, description, etc.) |
| `get_skill_body` | `skill_id` | Load the full markdown instructions |
| `get_skill_reference` | `skill_id`, `name` | Read a reference document |
| `get_skill_script` | `skill_id`, `name` | Read a script |
| `get_skill_asset` | `skill_id`, `name` | Read an asset |

All tools are async-compatible (`StructuredTool` with `coroutine`).

## API

### `get_tools(registry: SkillRegistry) -> list[StructuredTool]`

Returns a list of LangChain structured tools bound to the given registry.

### `get_tools_usage_instructions() -> str`

Returns a markdown string explaining the progressive-disclosure workflow - read metadata, then body, then fetch resources on demand. Designed for system-prompt injection alongside the skill catalog.

## Example

See [examples/langchain/](../../examples/langchain/) for a full working demo.

## Error Handling

| Scenario | Exception |
| --- | --- |
| Skill not found in registry | `SkillNotFoundError` |
| Resource not found in skill | `ResourceNotFoundError` |
| Provider errors (HTTP, filesystem) | `AgentSkillsError` |

All exceptions inherit from `AgentSkillsError` (from `agentskills-core`).

> **Note:** Binary content (scripts, assets, references) is decoded as UTF-8 with `errors="replace"`. Non-decodable bytes are replaced with the Unicode replacement character (�).

## License

MIT