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

Annotations only cover the safety profile (readOnly/idempotent/non-destructive), and the description goes well beyond that with the ranking model: giving volume toward the requested cause and region, tie-breaks by name then slug, and explicit deprioritization of single-recipient givers, related-organization funders and pass-through donation platforms. That ranking behavior is not derivable from the schema or annotations and materially affects how an agent should present results.

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?

Four sentences, each doing distinct work: purpose, ranking and tie-break logic, scope limitation, and handoff. Front-loaded with the capability before the ordering detail, with no restatement of the name or title.

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?

An output schema exists so return values need not be described, and the description covers the remaining unknowns an agent needs: how results are ordered, what that ordering does and does not mean, and how to continue into funder_profile. Nothing required to call or interpret the tool correctly 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?

Schema coverage is 100%, so the baseline is 3, but the description adds non-obvious semantics: cause_area and region_code do not merely filter, they drive the relevance ordering. It does not clarify that all six parameters are optional and that omitting them yields an unfiltered ranked list, which would have earned a 5.

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?

Opens with a specific verb and resource plus the exact filter dimensions ('Find funders by jurisdiction, cause area, size band and region'), which immediately separates it from funder_profile and opportunity_search. The closing sentence makes the sibling relationship explicit by naming funder_profile as the retrieval step.

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?

Clear on when to use it (filtering the funder corpus) and explicitly bounds interpretation with 'it is not a fit assessment for any organization', plus a concrete next step via funder_profile with the returned slug. No guidance on how it relates to opportunity_search or why one would pick it over a profile lookup, so it stops short of full alternative routing.

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