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

The description explains the surprising annotation profile: despite being a read, the first call 'issues version 1', which accounts for readOnlyHint=false, and the live-read-on-every-call semantics align with openWorldHint=true and idempotentHint=true. What it does not add is any auth, rate-limit, or failure behavior, but the core side-effect disclosure is genuinely useful beyond the annotations.

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 payload list are front-loaded in the first sentence, with the live-read caveat and parameter definitions following. Slightly dense and clause-heavy, but every sentence carries information an agent needs.

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 two-parameter tool with an output schema (so return shape needn't be restated), the description covers what the passport contains, that results are fetched live, and that the first call creates version 1. The one real gap is sibling disambiguation against verify_passport and list_passports.

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?

Schema description coverage is 0%, so the description carries the full burden and does: 'subject' is defined as a GTIN of 8–14 digits OR a market/banner string such as FR/Carrefour, and 'kind' is defined as gtin or banner and marked optional. This supplies format, allowed values, and optionality that the bare schema lacks.

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 gives a specific verb+resource ('the signed passport of a product ... or a retail banner') and enumerates the payload an agent gets back: hub ownership, record location, compliance records, listings, payment door. It neatly separates the GTIN case from the market/banner case, though it never names the siblings list_passports or verify_passport, so the agent must infer the distinction itself.

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?

There is no statement of when to call this versus list_passports or verify_passport, nor any prerequisite or exclusion. 'Read live from the GSC hubs on every call' describes runtime behavior rather than selection guidance, leaving the routing decision entirely to inference.

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