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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds meaningful context beyond that: the data provenance (USGS MRData) and an explicit inventory of what the record contains, which is important given there is no output schema. It says nothing about failure behavior for an unknown id or about how sections filtering affects the payload.

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 leads with what the tool returns and follows with the field inventory. The enumeration is long but earns its place because no output schema exists to describe the return shape.

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 compensates by enumerating the returned fields (commodities, deposit type, production years, host rocks, bibliography), which is exactly the context an agent needs. It is thin only on edge cases such as an invalid or missing deposit id.

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%: dep_id carries an example and a pointer to mrdata_search_deposits, and sections is documented as a comma-separated keep-list. The description adds no syntax, format, or default information beyond what the schema already provides, so the baseline of 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 resource (full USGS MRDS record) and a precise scope (one deposit, by its deposit id), and the field inventory makes clear this is a detail fetch rather than a listing. It does not name mrdata_search_deposits as the sibling it contrasts with, so differentiation is implicit rather than explicit.

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 phrase 'for one mineral deposit by its deposit id' implies lookup-after-search usage, but the description never states when to use this versus mrdata_search_deposits or mrdata_commodities, nor any prerequisites or exclusions. The only routing hint ('Get one from mrdata_search_deposits') lives in the schema, not the description.

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