MCP Tool Output Schema
Industry Definition Set • Entity Resolution Path: /glossary/mcp-tool-output-schema
Quick Answer / TL;DR
The JSON Schema that defines the expected structure of an MCP tool's successful result.
Key Takeaways
- Describes the structure of a tool's successful result.
- Optional but recommended for complex results.
- Helps clients and models understand output structure.
- Follows JSON Schema Draft 7.
Definitive Statement: The JSON Schema that defines the expected structure of an MCP tool's successful result.
Technical Context & Protocol Usage
- Detailed Explanation
- While less commonly enforced than input schemas, output schemas describe what a tool returns on success. This helps clients and models understand the result structure and enables automated documentation generation. Output schemas are optional but recommended for complex tool results.
Format & Payload Metadata
Format: JSON Schema Draft 7
Latency: No overhead; documentation and validation aid
Real-World Implementation Use Case
A `database_query` tool declares an output schema describing an array of row objects with typed columns.
Cite This Page
MLA Style:
MCPserver.in Engineering. "MCP Tool Output Schema." MCPserver.in Knowledge Hub, 20 July 2026, mcpserver.in/glossary/mcp-tool-output-schema.
Related Terms
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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)
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