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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds real value beyond them by disclosing the free-plan rate-limit quirk (limits halved for API/agent access), which materially affects how an agent interprets returned usage numbers.

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 short sentences with zero waste: identity/return contents first, then the call-ordering cue, then the plan caveat. Every sentence earns its place and it is front-loaded.

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 parameters, no output schema, and annotations already covering the safety profile, the description fully covers what the tool returns and the one counterintuitive caveat about plan limits. Nothing needed to invoke it correctly 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 input schema has zero parameters, so the baseline is 4. There is nothing to disambiguate and the description correctly implies a no-argument call.

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 resource and enumerates its contents: token owner, plan, credit balance, and current-month usage against limits. Among siblings that are all action-oriented (transcribe, export, checkout), this is clearly the read-only account-status tool.

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?

Gives an explicit call-ordering directive: 'Call first: it tells you what is allowed before you spend anything,' which tells the agent when this tool is valuable. It does not name alternatives or when-not-to-use, but no sibling competes for this role.

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