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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so safety is covered. The description adds genuinely useful context by disclosing the breadth of the returned profile (priorities, language tips, mistakes, required documents, form questions, rounds), which is valuable since there is no output schema. It does not clarify error behavior for an unknown slug.

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?

One tight sentence with the resource scoped up front and the field enumeration after the colon; the trailing usage hint earns its place. The list is dense but every item is informative given the absent output schema.

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 carries the return-value burden and does so well by naming the profile sections. It stops short of stating error cases (invalid/missing slug) or whether the profile is cached, which would be the remaining gap for a single-param lookup tool.

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 100% and the single slug parameter is documented in the schema as coming from search_funders. The description only restates 'by slug' and adds no format, length, or validity nuance beyond what the schema provides, so the baseline of 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+resource ('Full profile for one funder by slug') and enumerates the payload contents, which clearly distinguishes it from siblings like search_funders or list_filters. An agent can tell this is the detail-fetch complement to the search tool 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?

Explicitly states the trigger: 'Use this before preparing or drafting an application.' It does not name sibling alternatives or when-not-to-use, but the search-then-fetch relationship is strongly implied by the slug parameter referencing search_funders.

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