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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the 'Read-only, free' clause mostly restates them (though 'free' is new). The description earns credit for disclosing provenance and currency of the data (OSHA QuickCard 3491, 2024) and that a guide page link is included.

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?

A single front-loaded sentence that opens with the input contract before listing outputs. It is dense but every clause (input forms, returned fields, data source) carries information; only the trailing 'Read-only, free' is close to redundant.

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 lookup with no output schema, the description fully enumerates what comes back: meaning, hazard classes, OSHA HCS requirement, and a guide page. It omits behavior for unrecognized or ambiguous pictogram input, which is the only notable gap.

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 schema already documents the single parameter with examples, so the baseline is 3. The description adds only the explicit GHS01-GHS09 range and a couple of name-form examples, which is marginal value over the schema.

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?

States a specific verb and resource: given a GHS pictogram code or name, returns its meaning. The scope is unambiguous and clearly distinct from the SDS-search siblings, which deal with documents rather than pictogram semantics.

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?

Makes the triggering context clear (you have a pictogram code GHS01-GHS09 or a colloquial name and want its meaning), and enumerates accepted input forms. It stops short of naming when to use a sibling tool instead or what to do if the pictogram isn't valid, so it falls just short of a 5.

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