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

The description discloses data source (PubChem live), response format (JSON), and payment information ($0.03 USDC per call). However, with no annotations, it fails to clarify that at least one parameter is required despite the schema allowing both to be optional.

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 front-loaded with the main purpose and lists contents concisely. It is slightly verbose with the full enumeration but remains clear and well-structured.

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?

The description covers all major aspects of the tool: input parameters, output contents, data source, and pricing. Given no output schema, it provides sufficient context for an agent to judge suitability.

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%, and the description adds 'by CAS number or name' which reinforces the two optional parameters. No additional format constraints or examples are provided beyond the schema descriptions.

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 tool provides a full safety profile for chemicals by CAS number or name, listing all included components (GHS classification, first-aid, etc.). It distinguishes itself from siblings like chem-compat by specifying the exact safety data provided.

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 implies use when needing a chemical safety profile but does not explicitly state when to use this tool vs alternatives. No when-not-to-use guidance or comparison to siblings like chem-compat is provided.

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