What is a tool call in MCP?

In MCP (Model Context Protocol), a tool call is a JSON-RPC request the agent sends to a server using the tools/call method. The request names the tool, supplies arguments that match the tool's input schema (returned by tools/list), and the server responds with a structured result the agent treats as grounded data.

How is a tool call different from a REST request?

REST requests are written by human developers using documented endpoints. Tool calls are made by agents at runtime after discovering tool definitions via tools/list — the agent doesn't need to know the endpoint URL or response shape ahead of time. Tool definitions describe themselves to the agent.

What does Hive's tools/list return?

Hive's tools/list returns hundreds of tool definitions across 10 category-scoped MCP endpoints — each with a name, description, JSON Schema for arguments, and metadata about which upstream provider serves the tool. Agents call any of them via tools/call without per-tool integration.

What is a tool call? | MCP Tool Call Definition for AI Agents

A tool call is how an AI agent invokes a function — a structured request that names the tool, supplies arguments validated against the tool's schema, and returns a structured response the agent can reason over.

In MCP specifically

The Model Context Protocol formalizes tool calls as a JSON-RPC method:

tools/list — returns the catalog of available tools, each with a name, description, and input JSON Schema
tools/call — invokes one named tool with validated arguments
The agent never hand-codes a tool wrapper; the schema travels with the tool definition

This is the protocol-level difference between MCP and a raw REST API. With REST, every tool is a custom integration the agent's developer writes. With MCP, every tool is self-describing and discoverable at runtime.

Why tool calls matter for crypto agents

Without tool calls, an agent answering "is this token a honeypot?" has to either rely on its training data (stale, often wrong) or have a developer pre-wire a GoPlus integration, parse the response, and feed it back to the model. With tool calls, the agent calls get_token_security directly with the token address — Hive's MCP returns a structured grounded answer with fetched_at timestamps.

Hive's catalog includes hundreds of crypto tool calls across 10 categories — market data, DeFi, security, wallet, NFT, DEX, prediction markets, token contract, network, and search. See the Live Catalog for the full list.

In MCP specifically

Why tool calls matter for crypto agents

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