MCP Tool Input Schema
Industry Definition Set • Entity Resolution Path: /glossary/mcp-tool-input-schema
Quick Answer / TL;DR
The JSON Schema that defines the valid parameters for an MCP tool, including types, required fields, and descriptions.
Key Takeaways
- Defines valid parameters for a tool.
- Used for client-side validation and model guidance.
- Should include types, descriptions, and required fields.
- Follows JSON Schema Draft 7.
Definitive Statement: The JSON Schema that defines the valid parameters for an MCP tool, including types, required fields, and descriptions.
Technical Context & Protocol Usage
- Detailed Explanation
- Every MCP tool must declare an `inputSchema` object describing its expected parameters. This schema is used by clients to validate arguments before sending them to the server, and by models to understand what values to provide. A well-defined input schema reduces errors and improves the quality of tool calls.
Format & Payload Metadata
Format: JSON Schema Draft 7
Latency: Validation is client-side and fast
Real-World Implementation Use Case
A `weather_lookup` tool defines its input schema with a required `city` string parameter and an optional `unit` enum.
Cite This Page
MLA Style:
MCPserver.in Engineering. "MCP Tool Input Schema." MCPserver.in Knowledge Hub, 20 July 2026, mcpserver.in/glossary/mcp-tool-input-schema.
Related Terms
Model Context Protocol (MCP)
An open, secure protocol that standardizes how artificial intelligence agents and large language models (LLMs) exchange context, tools, prompts, and data resources with external servers.
JSON-RPC 2.0
A lightweight, stateless remote procedure call (RPC) protocol defined in JSON that utilizes request, response, and notification message frames.
Stdio Transport (Standard Input/Output)
A local-only transport mechanism where the AI client spawns the MCP server as a child process and communicates via standard input (stdin) and standard output (stdout) channels.
SSE Transport (Server-Sent Events)
A lightweight, unidirectional HTTP-based streaming protocol used by remote MCP servers to push messages to AI clients, with client-to-server writes sent over standard POST requests.
Deploy Secure MCP Clusters
Run remote SSE Model Context Protocol servers in highly secure, fully-managed environment located inside India (Mumbai/Bengaluru).
Deploy Node Now