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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful context beyond that: output structure (confidence tiers, ranked funders, amounts, grant counts, filing years), the historical-evidence limitation, and the quota note that it does not count toward monthly searches. No contradiction with annotations.

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 with no filler; the core purpose is front-loaded and each subsequent sentence adds a distinct piece of useful information (output details, exclusions, quota impact). Dense but efficient, with the only minor issue being one long sentence that packs many return details together.

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?

Given no output schema, the description does a good job explaining what results look like and what the data does and does not represent. It covers data source, confidence tiers, ranking, filing years, exclusions, and quota. It does not explicitly walk through pagination or state filtering, but those are documented in the schema, so the description is sufficiently complete for invocation.

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%, so the baseline is 3. The description reinforces the organization-name matching idea but does not materially add detail beyond what the schema already documents for page, limit, state, or organization. It earns the baseline rather than exceeding it.

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 ('Find') and a precise object: private foundations whose covered 990-PF filings name a given organization as a grant recipient. This clearly distinguishes the tool from siblings like search_foundations or funders_for_cause by describing the exact data source and relationship being searched.

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?

Provides an explicit use case: researching who funds peer organizations doing work like the user's. It also includes important exclusions ('NOT an open call, a current interest statement, or an eligibility signal'), though it does not name specific alternative sibling tools or conditions for choosing them.

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