Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so safety is covered. The description adds that parsing yields components and that close-code decoding is optional, but says nothing about behavior on an invalid URL (error vs. result) or the meaning of 'components'.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single well-formed sentence that front-loads the primary operation and appends the optional secondary capability. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be described. Both parameters are acknowledged and the operation is fully stated, though the absence of invalid-input behavior and close-code semantics leaves minor gaps for a two-parameter validation tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With schema description coverage at 0%, the description must compensate. It clarifies the second parameter's purpose ('optionally decode a WebSocket close code') and hints at the URL format (ws:// or wss://), but gives no guidance on the valid close-code range (1000-4999) or URL syntax details.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb pair (validate and parse) plus a tightly-scoped resource (ws:// or wss:// URLs), with an additional capability (decode close code) called out. The ws/wss restriction inherently distinguishes it from generic siblings like url_codec and validate_sitemap.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the narrow scope but never stated explicitly. There is no 'use this when...' guidance and no routing to url_codec for non-WebSocket URLs, leaving the agent to infer when this is the right tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.