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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description correctly does not need to restate safety. It adds meaningful behavioral context by describing the underlying IRS data source, the ~2M-org scope, and the exact recipient-side funding signals returned in each result. No contradiction with annotations is present.

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 longer than minimal, but every section earns its place: the opening defines scope, the middle explains result content, and the closing provides tool-selection guidance. It is structured with clear headings and front-loaded with the most important distinction (grantee vs. funder). Slightly verbose because of the inline code fields, but well organized.

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 15-parameter tool with an output schema, the description is complete: it explains the domain, the result payload, the key tool-routing decisions, and the likely downstream workflow. The schema covers the remaining parameter details, and the output schema handles return-value expectations. Nothing essential is missing for correct tool selection and 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 87%, so the schema already carries most parameter meaning. The description adds useful high-level context about the result fields (total_grants_received, funder_count, etc.) and mentions broad use cases, but it does not add per-parameter guidance beyond what the schema provides. Baseline 3 is appropriate.

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 action and subject ('Search the ~2M-org universe of US nonprofits (IRS Business Master File)') and explicitly positions it as the 'RECIPIENT / grantee side, distinct from search_funders'. This clearly differentiates it from its primary sibling tool, so an agent can identify what it does without ambiguity.

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 'CHOOSING THE RIGHT TOOL' section provides explicit conditional routing: use search_funders when the intent is to find funders to apply to, use search_nonprofits for recipient benchmarking, and use get_foundation_grants/search_funders after finding a well-funded peer. This is clear, actionable guidance with named alternatives.

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