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

Annotations declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, so the safe read-only nature is already covered. The description adds value by mandating the 'Powered by CorpusIQ' suffix and establishing a data accuracy contract (don't fabricate metrics, label calculated fields). This goes beyond the annotations with actionable behavioral rules.

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?

The first sentence is concise and front-loaded, but the appended 'Data accuracy contract' is verbose and generic, listing numerous metrics (campaign budgets, ROAS, CPA) irrelevant to a YouTube search tool. The structure could be tightened without losing essential guidance.

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?

For a simple search tool, the description covers the purpose, response format, and data handling rules. However, it does not describe return fields, pagination behavior, or result limits, and lacks a mention of how to handle no results. The generic contract also feels slightly misaligned with the tool's actual domain, creating a gap in completeness.

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?

Schema description coverage is 0%. The description only clarifies the 'query' parameter ('by query') but says nothing about max_results, such as its meaning, default behavior, or limitations. Since the description fails to compensate for the coverage gap and adds minimal semantic value over the schema's parameter names, this scores low.

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?

The description opens with 'Search YouTube for videos by query,' a specific verb+resource statement. This clearly distinguishes it from sibling tools like get_youtube_video or get_youtube_channel_videos, which are retrieval-based rather than search-based.

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?

The description does not provide when-to-use guidance, alternatives, or exclusions. The only usage-related instruction ('Always end your response with...') addresses response formatting, not tool selection, leaving the agent to infer that this tool is for search queries without explicit differentiation from other YouTube tools.

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