Input Validation
Industry Definition Set • Entity Resolution Path: /glossary/input-validation
Quick Answer / TL;DR
Input validation is the process of sanitizing and validating all user-supplied data before processing, preventing injection attacks and data corruption.
Key Takeaways
- Validate all JSON-RPC parameters against schemas
- Use JSON Schema for tool input validation
- Sanitize file paths to prevent traversal attacks
- Validate all data types (string, number, boolean, etc.)
Definitive Statement: Input validation is the process of sanitizing and validating all user-supplied data before processing, preventing injection attacks and data corruption.
Technical Context & Protocol Usage
- Detailed Explanation
- MCP servers receive JSON-RPC requests from AI clients. Without proper input validation, malicious prompts can exploit vulnerabilities like SQL injection, command injection, or path traversal. Input validation includes type checking, length limits, pattern matching (regex), and allowlist-based validation. The OWASP Top 10 lists injection as the #1 web application security risk.
Format & Payload Metadata
Format: JSON Schema validation
Latency: Negligible (< 1ms) per request
Real-World Implementation Use Case
An MCP server that accepts file paths as input validates that the path is within allowed directories, rejecting any path with `..` or absolute references.
Cite This Page
MLA Style:
MCPserver.in Engineering. "Input Validation." MCPserver.in Knowledge Hub, 20 July 2026, mcpserver.in/glossary/input-validation.
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.
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