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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the tool is clearly safe. The description adds behavioral context by specifying that it returns passages with citations and does not generate answers, and it details the sources covered (A1C articles and NCCIH monographs), which goes beyond 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 two sentences long, front-loads the core purpose, and adds clarifying scope and behavioral notes without any extraneous words. Every sentence earns its place.

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?

Given there is no output schema, the description adequately explains that the tool returns 'matching source passages with citations' and 'retrieved text for the caller to reason over'. This is sufficient for an agent to understand the tool's output without additional detail.

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 both parameters are already documented. The description adds extra guidance for the 'query' parameter: 'Pass the substantive question only — do not include conversation history or anything about who is asking'. This improves parameter usage beyond the schema's basic description.

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 clearly states the verb 'search', the resource 'Sally's preventive and metabolic health library', and what is returned: 'matching source passages with citations'. It distinguishes the tool from siblings by specifying the library's scope (clinical articles and NCCIH monographs), which differentiates it from other health tools like 'lookup_food' or 'analyze_lab_result'.

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 explicitly states that the tool returns text for the caller to reason over and does not write an answer or give medical advice, which guides appropriate usage. However, it does not explicitly list when not to use it or suggest alternative tools, though the sibling list provides implicit context.

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