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

Beyond the readOnlyHint annotation, the description discloses substantial runtime behavior: it never returns a bare empty result, explains the result_path values ('direct', 'broadened', 'redirected'), and reveals that entity_mode='exact' excludes off-genus rows and reports that exclusion count. This goes well beyond what annotations could convey.

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 average but every sentence adds either scope clarification, a concrete example, an edge-case guarantee, or a parameter-use caveat. It front-loads the core purpose before diving into behavioral details, though it could be lightly restructured into shorter logical blocks for even easier scanning.

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 9-parameter search tool, the description covers the key decision points: result_path semantics, pagination with offset, entity_mode disambiguation, snippet vs full notes, and archive filtering. Since an output schema exists, the agent has the remaining return-shape details, making this definition complete for correct 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 100%, and the schema already documents query, limit, offset, archive, year filters, n_results, entity_mode, and include_full with concrete examples. The description repeats some of this and adds extra illustrative match counts and behavior around paging, but the schema already carries the heavy lifting, so the baseline of 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 opens with a specific verb and resource ('Full-text keyword search across all archive colour names and notes') and enumerates the axes of search ('name fragment, material, cultural reference, pigment type, or historical period'). It also distinguishes itself from conceptual embedding search by stating it performs exact keyword matching, which is relevant given sibling tools like query_conceptual.

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 clearly says it complements conceptual embedding search, implying when exact keyword matching is preferred, and it explains when to switch entity_mode from 'text' to 'exact' for botanical identity. It does not explicitly name the sibling tools or state when NOT to use archive_search, but the context is strong enough for an agent to choose it appropriately.

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