fda_substance

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

Annotations already declare readOnlyHint=true, so the description's 'Search' is consistent. The description adds useful context about the search query syntax and field formats but does not elaborate on other behavioral traits like pagination or rate limits. It adds value beyond annotations but does not cover deeper behavioral details.

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 very short, front-loaded with purpose, and uses bulleted examples efficiently. Every sentence adds value without redundancy.

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 the large number of sibling tools (many FDA-related), this description clearly differentiates the tool by focusing on substances and providing query examples. It covers essential aspects: data type, search fields, and syntax. The lack of output schema is acceptable for a search tool, and the description is complete enough for an AI agent to understand its use.

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?

Both parameters are fully described in the input schema (100% coverage). The description reinforces the schema by showing concrete field names and formats in examples, but it does not add new meaning beyond what the schema already provides. 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 explicitly states 'Search FDA substance data — molecular-level ingredient information' and provides specific search examples (by name, CAS code, UNII, molecular formula). This clearly distinguishes it from sibling FDA tools like fda_approved_drugs or fda_drug_labels, which deal with drugs rather than substances.

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 gives concrete example queries for different search fields, indicating when to use this tool (e.g., when you need molecular-level ingredient info). It does not explicitly state when not to use it or mention alternatives, but the examples and context of sibling tools provide sufficient differentiation.

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