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

Annotations already cover readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond those: it promises to return a confidence level, a PDF link, and, crucially, says it will 'say so plainly rather than guessing' when identification fails. That transparency about failure mode is useful behavioral information not available from 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 compact and front-loaded: what it does, what it returns, the failure behavior, and the use case all appear in a natural order in three sentences. Every sentence carries distinct information, and there is no filler or repetition of the title.

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 single-parameter, read-like tool with no output schema, the description is complete. It names the input concept, the output fields, the confidence signal, the failure behavior, and access requirements ('Free, no signup'). An agent has enough information to call it correctly and interpret the result even without seeing the output schema.

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%, with a clear required 'product' property and examples like 'acetone' and 'Clorox disinfecting wipes.' The description only adds minor semantic context by emphasizing lookup 'by name,' which matches the schema. Since the schema already carries the parameter meaning, the descriptions contribution is baseline.

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: 'Look up the manufacturer safety data sheet (SDS/MSDS) for a workplace chemical or product by name.' It also lists the concrete return fields, making the function unmistakable. This is clearly distinct from the sibling tool check_hazcom_readiness, which implies a compliance-checking purpose rather than document lookup.

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 an explicit trigger: 'Use it when someone needs hazard or handling information, or the SDS, for a chemical they keep on site.' It does not, however, state when not to use it or explicitly route the agent to check_hazcom_readiness as an alternative, so it stops short of full exclusion guidance.

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