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

With no annotations provided, the description carries the transparency burden. It discloses the return value (W3C VC or a self-registration next step) and the offline verification mechanism. It does not cover permissions or side effects, but for a read-oriented credential fetch, it is largely transparent.

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 front-loaded with the core purpose and provides use-case context, examples, and edge-case behavior. It is slightly dense but every sentence adds value; no filler or redundancy.

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 single-parameter tool with an output schema, the description covers the parameter format, expected output, error/edge case (unregistered identity), and usage context. It is complete enough for an agent to select and invoke the tool correctly.

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 coverage is 0%, so the description must explain the parameter. It does so thoroughly: agent_id accepts either a Guild agent_id or a registered W3C did, and it provides concrete examples (agent_9x, did:key:z6Mk...). This adds significant meaning beyond the bare string schema.

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 with a specific verb and resource: 'Get a portable, Guild-signed Agent Passport'. It clearly distinguishes this tool from siblings by explaining the passport is for carrying to counterparties and pointing to guild_verify for verifying others' passports.

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?

It explicitly states when to use the tool ('Show YOUR passport to agents you want to work with') and names the alternative for the reciprocal action ('verify THEIRS with guild_verify'). It also handles the unregistered-identity case with a self-registration next step, which is clear usage guidance.

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