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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real domain behavior beyond them: the survey vintage, the bookmobile exclusion rule, the straight-line distance caveat, and that card eligibility is reported separately rather than used as a filter. It does not cover pagination behavior (cursor/limit) or what 'partial coverage' and the strict flag actually mean, which are the notable remaining gaps.

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?

Two tight sentences with the scoping caveats front-loaded before the attribution boilerplate; nothing is redundant. The trailing 'Served by Profullstack' line is filler for tool selection but is brief and clearly separated.

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, zero-required tool with no output schema, the description is adequate on scope but silent on the response shape (what a branch record contains, how next_cursor/paging works) and on what the strict flag's 'partial coverage' failure mode means. An agent can invoke it, but cannot predict the result structure.

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 every one of the 15 parameters is already documented in the schema, establishing the baseline of 3. The description adds only marginal semantic value, notably that radius_miles refers to straight-line distance and that the type filter is the lever for including bookmobiles.

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 first sentence names a specific verb-implied resource (public library branches) plus the scope (within a radius) and data provenance (IMLS FY2024 survey), which is far more concrete than the title alone. It does not explicitly contrast itself with neighboring dataset tools such as education_search or loc_search, so it stops short of a 5.

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?

It discloses useful selection rules — bookmobiles are excluded unless 'bookmobile' is in type — but never states the precondition for calling it, e.g. that a location anchor (lat+lng, zip, or city+state) is needed. An agent must infer from parameter names which input combinations are valid, so guidance is implied rather than stated.

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