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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety bar is low, but the description adds real context beyond them: the profile is derived from public videos or Reels only, YouTube profiles include subscriber and video counts, and the tool is explicitly not an analytics source for per-video views, last-video performance, or Instagram reach. That capability-boundary disclosure is exactly what prevents misinvocation.

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?

It is front-loaded with the core constraint ('only to read the user's own already-connected account') before the enumerations and exclusions. It runs long and repeats the 'not other people's channels' exclusion twice (once mid-text, once at the end), which costs some economy without adding information.

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?

There is no output schema, and the description compensates by describing the return payload (Tukey's profile with content pillars, formats, voice, hooks, audience, subscriber/video counts) and its data provenance. For a zero-parameter tool, nothing an agent needs in order to call it correctly or avoid calling it is missing.

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?

The tool takes zero parameters and the schema is an empty object, so there is nothing for the description to disambiguate. The description implicitly clarifies that the target account is fixed by the authenticated user's connection in Tukey, which is the only 'parameter-like' semantic that matters here.

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 a precise verb+resource+scope: read the user's OWN already-connected YouTube channel or public Instagram account, and states what the tool returns (Tukey's profile built from public videos/Reels, with subscriber and video counts). It explicitly distinguishes itself from identifying or comparing other creators' accounts, so an agent can separate it from siblings without opening a schema.

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?

It gives explicit when-to-use triggers (content pillars, formats, recurring series, voice, hooks, audience, subscriber/video counts, or pre-planning context for titling/pitching a video or Reel) and explicit when-NOT-to-use cases (someone else's channel, general YouTube/Instagram advice, per-video analytics, Instagram reach/audience data). It also names the alternative behavior for identification tasks ('look those up elsewhere').

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