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Tools let agents take actions, not just answer questions. When an agent has tools configured, it can call external APIs, query databases, send messages, and interact with any system that exposes an HTTP endpoint.

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How tool calling works

  1. The agent receives a user message.
  2. The LLM evaluates whether the message requires a tool call.
  3. The LLM generates a structured function call with the tool name and arguments.
  4. Lyzr executes the tool and returns the result to the LLM.
  5. The LLM incorporates the result into its final response.
Lyzr follows the OpenAI function-calling standard and handles execution, authentication, and retry logic so agents don’t require custom glue code.

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Types of tools

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Pre-built tools

A library of ready-to-use integrations. Navigate to Tools in the sidebar, select a tool, and authenticate with OAuth or an API key. Categories include: Email (Gmail, Outlook), Calendar, Slack, Notion, Salesforce, GitHub, Google Sheets, Jira, HubSpot, Discord, ClickUp, and more.

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Custom tools

You can define your own tools by providing an OpenAPI spec or a JSON schema for the function. Custom tools support three authentication modes:
  • API Key
  • OAuth 2.0 (with custom token and refresh URLs)
  • No authentication
Lyzr manages token storage, refresh cycles, and execution; you define the spec.

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MCP servers

Connect any Model Context Protocol (MCP) server by providing its URL. See the MCP integration guide.

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Tool auth in multi-user deployments

When an agent with tools is deployed to end users, you choose one of two auth modes: Shared auth means all users share the same tool credentials. The agent calls the tool using the account authenticated during setup. Use this for internal tools where all users should share a service account; for example, posting to a shared Slack channel. Per-user auth means each end user authenticates with the tool individually. The agent uses each user’s own credentials when it calls the tool. Use this for user-facing tools; for example, an agent that drafts and sends email from the user’s own Gmail account. Per-user auth works even when the end user is not a Lyzr Studio account holder. The OAuth flow is handled at inference time.

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Open-source tooling

Lyzr tooling is available open-source via ACI.dev. Enterprise on-premise deployments can self-host the tooling layer, keeping all OAuth tokens and credentials within their own infrastructure.

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Next steps