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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the bar is lower. The description adds value by disclosing data provenance (USGS MRData), the shape of the result (site count per commodity), and a dual mode where omitting bbox yields a symbol reference list.

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?

Three tight sentences, front-loaded with the core purpose and then the workflow relationship; every clause earns its place and nothing is 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?

With no output schema, the description does the work of explaining the return shape (counts per commodity) and the alternate reference-list mode. For a simple 2-optional-parameter read tool this is essentially complete; only pagination/size-of-result limits are unaddressed.

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 schema already documents bbox format, the omit-behavior, and sample_size defaults/limits. The description adds no format or constraint detail beyond the schema, making the baseline 3 correct.

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+resource ('Which commodities are recorded in USGS MRDS inside an area, with a site count per commodity') and differentiates itself from siblings by naming mrdata_search_deposits. An agent can distinguish this from mrdata_deposit and mrdata_search_deposits 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 a clear situational framing ('the "what is this region mined for" tool') and explicitly ties itself into a workflow as the symbol lookup that mrdata_search_deposits expects. No explicit when-not or exclusion guidance, so it stops 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.