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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds useful provenance details beyond annotations: the record is signed, comes from gtinfetch.ai, and is read live from the A2A Grocery door. It does not cover auth requirements or rate limits.

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 description is fairly compact, but the opening clause 'hub layer: seat, market, claim, price, availability' is cryptic and not explained. The core purpose is present but not front-loaded with maximum clarity.

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 described, and annotations cover safety. However, the single input parameter remains underspecified, and the description's jargon around hubs, seats, markets, claims, and prices is not grounded enough for an agent to fully understand the result context.

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 schema has 0% description coverage for the single gtin parameter, so the description must compensate. It expands GTIN and says the tool checks whether it is well-formed, but it does not specify accepted formats, checksum rules, or examples.

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 states a specific action: confirm whether a GTIN is well-formed and exists on the grocery record with brand and maker. It names the resource and outcome clearly, though it does not differentiate this tool from sibling resolve_* or lookup tools.

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?

The phrase 'Confirm the product is real' implies the tool's use case, but there is no explicit guidance on when to choose this over alternatives or when not to use it. Usage is inferable rather than stated.

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