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

Annotations already declare this is a read-only, idempotent, non-destructive, closed-world operation, so the safety profile is covered. The description adds useful context about the payload contents and even a token-cost comparison to get_started, which is behavior beyond the annotations. It doesn't discuss auth or rate limits, but those are minor for a no-param read.

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 purpose and returned fields are front-loaded in the first sentence, with the sibling comparison second. The enumeration of fields is dense but each item maps to a real part of the payload; it is appropriately sized for a tool with no schema to explain the return shape.

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, so the description must convey what comes back, and it does so by enumerating plan status, video counts, renewal dates, quotas, voice, subscription, and locked features. That is substantially complete for a read-only account snapshot, though it doesn't describe the response structure or formatting.

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, so the baseline is 4 per the rubric. The description adds no parameter meaning because none exists, and nothing is missing.

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 the resource: the user's current plan, remaining videos, renewal/trial dates, project quotas, voice, subscription, and locked features with unlock paths. It distinguishes itself from get_started but does not clarify how it differs from the sibling get_plans. An agent can tell what it returns, though one sibling comparison is left ambiguous.

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 explicitly names an alternative ('Cheaper than get_started when you only need the plan'), giving a clear selection condition. It doesn't mention when to prefer get_plans or get_started instead, so the routing guidance is one-sided rather than complete.

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