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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description goes beyond this by revealing fuzzy name matching behavior, the NCUA call report data source, the specific fields returned, and that the API is keyless. This adds meaningful operational context without contradicting the 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 slightly longer than necessary but front-loads the core purpose and includes valuable examples and example calls. Every component—fuzzy matching, return fields, natural-language intents, and keyless access—earns its place, with only minor redundancy in repeating the search examples.

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, optional-parameter search tool with no output schema, the description enumerates return fields and gives multiple call examples plus parameter semantics. It is largely complete; the only minor gap is not clarifying whether name, city, and state are combinable or whether filters are mutually exclusive.

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 adds value beyond the schema by explaining that name matching is fuzzy, connecting the parameters to natural-language intents, and demonstrating combination examples such as { state: "OH", limit: 25 }, which helps an agent select and format parameters correctly.

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 opens with a specific verb and resource: "Find US credit unions by name, city or state" and further specifies the data source (NCUA call report data). It also gives concrete natural-language questions it answers and concrete examples, making the tool's purpose unmistakable and distinct from most NCUA sibling tools.

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 provides clear example use cases and query patterns such as "credit unions in Austin Texas" and nickname-style searches like "navy fed". However, it does not explicitly state when to prefer this tool over the many NCUA siblings, such as ncua_branches, ncua_credit_union_profile, or ncua_compare_credit_unions, nor does it state exclusions.

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