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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds substantial behavioral context beyond them: restricted fields are listed as withheld rather than shown, links from other resolvers are refused not fetched, and no auth is required. That is exactly the extra context the annotations do not carry.

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 it does, then the identifier forms, then the critical disambiguation from verify_chip. Every sentence carries information, though the run is slightly long and could be tightened.

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 output schema, the description compensates by enumerating return contents (signed fields, version and date, recall status, item links) and by covering auth, refusal, and sandbox caveats. Nothing needed to call 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?

Schema description coverage is 100%, so all four parameters (date, dpp_id, version, digital_link) are already documented, including the dpp_id/date/version pairing rules. The description confirms the accepted identifier forms but adds little syntax beyond what the schema states; baseline 3 applies.

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 and resource ('Read the PUBLIC view of a published Digital Product Passport') plus the two accepted identifiers. It explicitly distinguishes itself from the sibling verifier ('use verify_chip... for that') and from verify_passport_credential territory, so an agent can select it without opening a schema.

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 when-to-use and when-not-to-use guidance: it reads the record only and does NOT prove the physical item, with a named alternative (verify_chip with a fresh chip tap). It also states the no-API-key condition and that sandbox org passports are not public in production.

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