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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is covered. The description adds essentially no behavioral context beyond the annotations — it does not explain what the passport contains, whether it accumulates over time, or what zones mean.

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 a single short sentence with no padding, so it is not verbose. However, the first clause is wasted on restating the title, and brevity here reflects under-specification rather than disciplined conciseness.

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?

An output schema exists so return values need not be explained, but the description still fails to convey what this tool semantically does or when to invoke it. For a tool whose whole concept is a metaphor, more grounding is required.

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?

There is only one optional parameter (api_key), fully documented by the schema at 100% coverage, and the description adds nothing about it. This matches the baseline of 3 when the schema does the heavy lifting.

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 by restating the title ('Your passport:'), which is close to tautology. The second clause ('stamps from each zone you have used') hints that it returns accumulated stamps, but no verb or resource is stated clearly and there is no differentiation from siblings like whoami or my_points — an agent cannot tell what a 'stamp' or a 'zone' concretely is.

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?

No indication of when to use this tool, when not to, or which sibling (whoami, my_points, tower_view) is the alternative. The agent must infer usage entirely from the metaphorical name.

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