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 safety profile is covered. The description adds genuinely useful coverage context by naming the specific national frameworks and databases held (HSE EH40, TRGS 900/GESTIS, INRS VLEP, OSHA Z-1, etc.), which is not derivable from annotations or the country enum alone.

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?

Purpose and exclusions are front-loaded, but the middle is a single sprawling sentence enumerating sixteen source documents, which is longer than selection requires. It is serviceable but not tight; a representative subset plus 'and other national OEL frameworks' would carry the same selection signal.

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?

An output schema exists, so return values need not be explained. The description covers scope, jurisdictional coverage, defaults and exclusions; only minor gaps remain, such as whether limits are returned in normalized units across jurisdictions.

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 the country enum, substance identifiers and limit_types defaults are already documented in the schema. The description adds only marginal parameter meaning via the limit acronyms in the title (MAC, STEL, AGW), which loosely maps to limit_types, so the baseline 3 applies.

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 ('looks up') and resource ('occupational exposure limits for a substance'), enumerates the limit-type acronyms it returns, and names the siblings it is not (search_regulations, get_ghs_hazard_classification). An agent can distinguish it from every sibling without opening a schema.

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?

Gives concrete use cases (SDS section 8, COSHH assessment, OSHA compliance check) and explicit exclusions: drinking water/ambient air/food limits route to regaffairs_search_regulations, hazard classification routes to regaffairs_get_ghs_hazard_classification. Both when-to-use and when-not are stated.

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