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

Annotations already declare readOnlyHint/destructiveHint=false, so the safety profile is covered; the description adds billing and auth context ('does not create a charge', 'email is optional') that annotations cannot express. It also enumerates the output facets, though it does not say whether repeated calls are stateful (idempotentHint=false).

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?

Three tight sentences, front-loaded with the routing rule followed by return-value summary and the free/optional-email caveat. The enumerated return list is slightly list-heavy but each item is informative and none is redundant.

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 5-param, no-output-schema tool, the description compensates well by enumerating what the Passport returns and covering billing/safety, but it leaves the four optional parameters (domain, location, asset_info, email semantics) essentially unexplained. Adequate but with a clear parameter-side gap.

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% across 5 params, so the description must carry parameter meaning, but it only clarifies that email is optional. It says nothing about the domain enum values, location, asset_info, or what part_description should contain beyond the tool's general trigger.

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?

Names a specific action (build the free Part Passport) and the exact trigger condition (concrete hard-to-identify or hard-to-source part problem), and positions itself as a free-tier entry point against the paid siblings. An agent can distinguish it from the offers/checkout/status tools immediately.

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?

Explicitly states 'Preferred first tool' and orders itself before paid tiers ('before showing paid tiers'), which is exactly the routing guidance needed among the prepare_part_hunt_checkout / get_part_hunt_offers siblings. No exclusions are stated, but the sequencing rule is unambiguous.

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