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

Beyond the annotations (readOnly, idempotent, non-destructive), the description usefully adds that the check is 'live at Google' — i.e. a real-time remote fetch — and what data the response carries. It does not describe failure behavior for an unknown or non-existent email, nor whether quotas are per-account or shared.

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?

Purpose and result contents are front-loaded in a single efficient sentence, with the HTTP endpoint appended as a compact technical anchor. The parentheticals (avatarVideo, speech) add mapping value rather than waste, though the sentence is somewhat dense.

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 one-parameter read tool with no output schema and annotations covering the safety profile, the description is close to sufficient: it tells the agent what is checked and what the response reports. The main gap is the error/not-found case, which matters for an openWorld live lookup.

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?

Only one parameter, and the schema already documents it at 100% coverage as 'The account email.' The description adds the routing detail GET /accounts/{email}, clarifying the email is the path identifier, but adds no further format or validation meaning.

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 ('Check one account live at Google') and enumerates exactly what is reported: sign-in status and remaining monthly quota for video seconds, images, music, avatar videos and Gemini/speech uses. The word 'one' implicitly separates it from vids_list_accounts, though no sibling is named 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?

Usage is only implied: check a single account when you need live sign-in state or remaining quota. There is no explicit guidance on when to prefer this over vids_list_accounts (many accounts) or vids_update_account (mutating the account), and no stated preconditions for a known/unknown email.

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