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

No annotations exist, so the description carries the full behavioral burden. It does disclose cost ('about $1.50 per 1,000 videos') and the free contact row per channel, which is genuine operational context, but it omits authentication needs, rate limits, or failure behavior for unreachable channels.

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?

Three compact sentences with the core purpose front-loaded and the billing note last. Minor redundancy in the return-field enumeration, but 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?

With no output schema, the description should clarify what a result row looks like; it partially does by naming returned fields and the contact row. However, for a tool whose name promises emails, it never clarifies how emails are surfaced or what happens when a channel has none.

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 coverage is 100%, so all five parameters are already documented in the schema, giving a baseline of 3. The description adds no parameter-level detail (e.g., the channel vs searchQueries mutual usage) beyond what the schema states.

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 and resource ('Resolve the contact email behind YouTube channels') and enumerates what is returned (videos, Shorts, views, likes, tags, publish dates). This clearly separates it from find_tiktok_creators and get_video_transcripts, though it never names those siblings explicitly.

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?

There is no guidance on when to choose this tool over find_tiktok_creators or get_video_transcripts, nor any preconditions or exclusions. Usage is only implied by the resource name and the list of returned fields.

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