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

Annotations already provide read-only, idempotent, and non-destructive hints. The description adds useful behavioral detail beyond those hints: a required-filter constraint despite schema-optional parameters, and a hard cap of 100 returned organizations. There is 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?

The description is short, front-loaded with the action and filter options, and every sentence earns its place: required-filter condition, use case, and result cap. There is no redundant filler.

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?

For a simple filtered lookup with strong annotations, the description covers the essential constraints: required filters, location dimensions, purpose, and maximum result count. It is not fully complete because it does not name sibling alternatives or describe the returned organization fields, but neither is critical for basic 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 schema already documents every parameter. The description only restates the location filter types and the requirement for at least one filter; it does not add new parameter-level semantics beyond what the schema provides.

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?

The description states a specific verb ('Find'), a resource ('tax-exempt organizations'), and a specific dimension ('by location: city, state, and/or 5-digit ZIP'). It is clearly different from siblings like nonprofit_search_name, though it does not explicitly name that sibling.

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 description explicitly states the key usage condition ('At least one filter is required') and gives a concrete use case ('discovering charities, churches, and foundations in an area'). It does not reference alternative tools such as nonprofit_search_name or nonprofit_lookup_ein, so exclusions are absent.

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