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

Annotations already declare readOnly/idempotent/openWorld, so the safety profile is covered. The description adds genuinely useful behavior beyond that: fuzzy tolerance to word reordering and spelling, and ranked output with named fields (EIN, location, IRC subsection). It does not discuss result caps beyond the schema's limit param.

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 short sentences, all front-loaded with the core purpose first, then matching behavior, then return contents, then the next-step pointer. Nothing is redundant or padded.

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 three-parameter read-only search with no output schema, the description covers purpose, matching behavior, returned fields, and follow-up tools. Combined with annotations that carry the safety profile, nothing an agent needs to call it 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 description coverage is 100%, so name, limit, and state are already documented in the schema. The description only restates the state filter at a high level and adds no syntax or format detail beyond what the schema provides, matching the baseline for a fully-covered schema.

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 (fuzzy-search tax-exempt organizations by name) with scope, and its 'by name' focus distinguishes it from the sibling nonprofit_search_location which searches by location. An agent can route between the two without opening either 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?

Explicitly routes the agent onward ('Use the returned EIN with nonprofit_details or nonprofit_lookup_ein') and explains the optional state filter. It lacks an explicit when-not statement (e.g., when to prefer location search), so it stops short of a full 5.

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