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

Annotations already declare readOnlyHint/idempotentHint/non-destructive, so the safety profile is covered. The description adds real value beyond that: it discloses that the token value is never returned, that latency cost is '1 request', and that the call doubles as a token validity check.

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?

Front-loaded with what is returned, followed by when to call it and a cost note. Dense but every clause earns its place; the long return-field enumeration is the only mild bloat, partially redundant with the output schema.

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 zero-parameter, read-only diagnostic with an output schema and full annotation coverage, nothing needed to invoke it correctly is missing — trigger conditions, cost, and the security guarantee on the token value are all present.

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 schema carries nothing to interpret and the baseline is 4. The description appropriately spends its words on returned fields rather than nonexistent inputs.

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+resource (get token info) and enumerates exactly what it returns: permission rules, plan limits, monthly usage counters. No sibling tool overlaps with this diagnostic scope, so an agent can distinguish it immediately.

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 explicit triggering conditions: 'Call it first when anything fails with an authentication or permission error, and before a large batch of writes.' This is when-to-use guidance tied to concrete failure modes, with no alternatives needed since no sibling covers this.

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