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

Describes the tool as free and no-quota, which adds useful behavioral info. However, with no annotations, the description could explicitly state it is read-only or non-destructive, which is only implied by 'health probe.'

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?

Two sentences: first packs return fields, second gives usage guidance. No fluff, every word earns its place.

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?

Given low complexity (no params, no output schema), the description adequately covers purpose and usage. Listing return fields compensates for absence of output schema, though return format could be elaborated.

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 zero parameters, schema coverage is 100%, so the description need not add parameter details. The baseline of 4 applies as the description adds no confusion.

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 clearly states it is a health probe for YouTube, listing specific returned data (tier, usage, caps, etc.). It distinguishes itself from sibling YouTube tools that focus on finding opportunities, generating videos, etc.

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?

Explicitly advises use on every cold start, providing clear context for when to invoke. Does not mention when not to use or alternatives, but the guidance is direct and actionable.

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