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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is fully covered and the bar is lower. The description contributes that the profile is 'public' and includes aggregate rating/review counts plus recent reviews, but says nothing about behavior for unknown slugs, pagination of reviews, or caching.

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?

A single front-loaded sentence with the action and identifier first, followed by the returned fields. The trailing field list is slightly enumerative but every item tells the agent something it would otherwise have to guess, so nothing is wasted.

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 correctly spends its words describing the returned profile contents, and the single parameter is fully documented in the schema. Only the failure case (slug not found) is left unaddressed, which is a small gap for a read-only lookup.

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% and the slug parameter's schema text already gives the example format and the source (search_funders or the fundingtracker.app URL). The description only repeats the lookup key as 'slug' and adds no syntax or format detail 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 ('Get one funder's public profile from the FundingTracker directory') and adds the lookup key ('by slug'), which cleanly separates it from the sibling search_funders. It also enumerates what the profile contains, so an agent knows what it gets without opening the 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?

The phrase 'by slug' implies this is a follow-up detail fetch after a search, but the description never names search_funders or states an explicit when-to-use/when-not rule. Usage is inferable rather than stated, so it sits at the minimum-viable level.

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