HumanLayer provides an API and SDK for integrating human oversight into AI agent workflows, specifically for high-stakes function calls. It targets developers building agentic systems who need to ensure safety and reliability when AI agents interact with the real world, offering a mechanism for human approval and feedback.

How It Works

HumanLayer operates by instrumenting function calls within AI agent frameworks. It uses decorators like @hl.require_approval() to intercept calls to sensitive functions, routing them for human review via channels like Slack or email. Alternatively, hl.human_as_tool() allows agents to proactively solicit human input or feedback during execution. This approach deterministically guarantees human involvement, mitigating risks associated with LLM hallucinations or errors in critical operations.

Quick Start & Requirements

• Install via pip: pip install humanlayer
• Install via npm: npm install humanlayer
• Supports Python and TypeScript/JavaScript.
• Integrates with LLMs (OpenAI, Llama, Claude) and frameworks (LangChain, CrewAI, ControlFlow).
• Examples available for LangChain, CrewAI, ControlFlow, and raw OpenAI client.
• Official Docs: https://humanlayer.dev/docs/quickstart-python
• Discord: https://humanlayer.dev/discord

Highlighted Details

• @hl.require_approval() decorator for blocking function calls until human approval.
• hl.human_as_tool() for general human interaction within agent workflows.
• Omni-channel support for human contact (Slack, Email, Discord planned).
• Granular routing of approvals to specific teams or individuals.
• Framework-agnostic design, compatible with any LLM and tool-calling framework.

Maintenance & Community

• Active development with a roadmap indicating planned features like SMS/RCS approvals and LlamaIndex support.
• Open-source contributions are welcomed.
• Community support available via Discord.

Licensing & Compatibility

• Licensed under the Apache 2.0 License.
• Permissive license suitable for commercial use and integration into closed-source applications.

Limitations & Caveats

Some integrations, like GripTape and Controlflow, are currently in Alpha status. Features such as SMS/RCS approvals, Discord approvals, and composite contact channels are still in the planning stages.