search_records

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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower, yet the description still adds value: it warns that results are leads needing verification, and describes the return shape (total matches plus page of summaries with NAID, hierarchy, holding unit, image count). It does not repeat the annotations but adds practical caution about trusting hits.

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?

Front-loaded with the core action, then usage guidance, then return format and sibling routing across three short paragraphs. Every sentence carries distinct information with no padding.

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?

With no output schema, the description compensates by describing the return value (match count plus page of summaries with key fields). Combined with the 100%-covered input schema, the annotation safety profile, and explicit sibling routing, an agent has everything needed to call and interpret this tool.

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 coverage is 100%, so the baseline is 3, but the description adds strategic meaning beyond the schema: it advises starting with `title` and a specific phrase and frames `query` as the fallback when a title search fails. That semantic framing of when to prefer one parameter over the other is not present in the 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 ('Search the National Archives Catalog for records') and explicitly differentiates itself from the sibling search_records_advanced by naming the conditions that select the other tool. An agent can tell the two search tools apart without opening schemas.

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?

Gives concrete when-to-use guidance ('Start with title and a specific phrase'), warns that a broad query buries hits, and names the alternative (search_records_advanced) with the exact triggers for switching (dates, record group, M-number, digitised-only). This is explicit routing rather than implied context.

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