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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so safety is covered. The description adds genuine non-annotation behavior: footnote codes (W, E, NA, '>50') are preserved verbatim and never coerced, and the tool is keyless (no auth needed). It does not describe return shape or result limits.

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?

One dense, front-loaded paragraph that leads with what is returned and follows with accepted inputs and output caveats. The parenthetical defining net import reliance is slightly redundant but earns its place by preventing misreading of a domain-specific term.

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?

No output schema exists, so the description correctly carries return-value detail: the 5-year window, the field list (production, imports, exports, consumption, price, employment, import reliance), and the raw-footnote caveat. For a keyless 1-parameter read tool this is complete.

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% (baseline 3), and the description still adds meaning beyond the schema: it confirms 'MCS code' is an accepted form and gives examples ('rare earths', 'platinum group metals') that broaden the schema's own example list, clarifying the identifier space.

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?

Names a specific verb+resource: 'U.S. salient statistics for one mineral commodity from the USGS Mineral Commodity Summaries.' The scope word 'one' implicitly distinguishes it from sibling mcs_list_commodities and mcs_country_comparison, though neither sibling is named explicitly.

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 input flexibility ('common name or the MCS code' with examples) but never states when to choose this over mcs_list_commodities or mcs_country_comparison, and offers no when-not guidance. Usage is only implied by the 'one commodity' scoping.

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