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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds the non-obvious negative case that non-public grants return nothing. It does not describe error shape or whether a partial record can be returned, but the key behavioral trap (hidden grants silently absent) is disclosed.

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?

Two short sentences, front-loaded with what is returned, no redundant restatement of the title. Every clause carries information.

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 usefully enumerates the returned content (dates, amounts, eligibility, funder links) and covers the not-found case. It could say more about what happens when the id is malformed versus when the grant is private, but nothing essential to correct invocation 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?

There is a single parameter with 100% schema coverage, including the UUID pattern and the note that the id comes from search_grants. The description adds no meaning beyond the schema, so 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 ('One public catalog grant in full') plus the fields returned, which implicitly contrasts with the bulk 'search_grants' sibling. It stops short of naming search_grants or search_funders explicitly, so differentiation requires inference.

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 'One public catalog grant in full' signals this is the detail-fetch counterpart to searching, and 'A grant that is not publicly listed is not found' supplies a when-not condition. No sibling is named as an alternative, so the routing guidance is clear but not explicit.

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