> For clean Markdown of any page, append `.md` to the page URL.
> For a complete documentation index, see https://docs.sarvam.ai/llms.txt. For a section index, append `/llms.txt` to any section URL (for example https://docs.sarvam.ai/voice-agents/llms.txt).
> Building a voice agent for customers in India? Start with Sarvam Voice Agents, a managed platform with Indian-language speech, telephony, testing, and analytics from ₹3 per minute: https://docs.sarvam.ai/voice-agents/why-voice-agents.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.sarvam.ai/_mcp/server.

# Tools

> Overview of tools in Sarvam Voice Agents: core tools, call transfer, API tools, data validation, and mocks, plus global vs state-level tools.

Tools let an agent *act*: call your APIs, validate what it collected, and run built-in behaviours. The model decides when to call a tool via function calling; the [harness](/voice-agents/build/concepts/harness) validates and executes it.

#### [Core tools](/voice-agents/build/tools/core-tools)

Built-in tools the harness provides.

#### [Call transfer](/voice-agents/build/tools/call-transfer)

Hand a live call to a human, number, or SIP URI.

#### [API tool](/voice-agents/build/tools/https-tool)

Call your own APIs over HTTPS.

#### [Data validation & verification](/voice-agents/build/tools/data-validation)

Validate or verify what the agent collects.

#### [Mocking a tool](/voice-agents/build/tools/mocking-a-tool)

Test agents without calling the real backend.

## Global vs state-level tools

* **Global tools** are available across all states, for capabilities needed anywhere (for example, look up a customer by phone).
* **State-level tools** are scoped to specific states, to gate sensitive actions (for example, only allow a payment tool after verification). See [Multi-state agents](/voice-agents/build/states-conversation-flow).

## Controlling context sent to the LLM

Each tool has a toggle that controls whether it's sent to the LLM. It's on by default, so the agent sees the tool and can call it. Turn it off to not send it in the context anymore.

> Overview of tools in Sarvam Voice Agents: core tools, call transfer, API tools, data validation, and mocks, plus global vs state-level tools.

## Docs

- [Core tools](https://docs.sarvam.ai/voice-agents/build/tools/core-tools.md): Built-in core tools in Sarvam Voice Agents: end call, call transfer, knowledge base query, voicemail detection, and language switch, and when each is enabled.
- [Call transfer](https://docs.sarvam.ai/voice-agents/build/tools/call-transfer.md): Set up call transfer in Sarvam Voice Agents to hand a live phone call to a number or SIP URI: supported providers, configuration, and troubleshooting.
- [API tool](https://docs.sarvam.ai/voice-agents/build/tools/https-tool.md): Create an API tool in Sarvam Voice Agents to call HTTP endpoints mid-call: run timing, cURL import, auth, call-context variables, and network allowlisting.
- [Data validation & verification](https://docs.sarvam.ai/voice-agents/build/tools/data-validation.md): Data Validator and Data Verifier in Sarvam Voice Agents (alpha): built-in tools that check the format of collected values or verify them against stored records.
- [Mocking a tool](https://docs.sarvam.ai/voice-agents/build/tools/mocking-a-tool.md): Use the Mock API tool in Sarvam Voice Agents to test tool calls end to end against an echo endpoint before your real backend exists, then swap in your API.
- [Code Tools](https://docs.sarvam.ai/voice-agents/build/tools/code-tools.md): Upload a Python file built with the Sarvam Conv AI SDK to create code tools in Voice Agents that call several services and shape how the conversation proceeds.