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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, covering the safety profile. The description adds value beyond these by stating the data source (geodiva.avo.alaska.edu), that no auth is required, and that the data is US Government public domain. It does not discuss rate limits or error behavior, but for a read-only single-record lookup the provided context is sufficient.

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?

The description is two sentences with no filler. The action and scope are front-loaded, the useful field list follows immediately, and the second sentence adds licensing/auth context that earns its place.

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 one fully documented required parameter, an output schema present, and annotations covering the read-only/idempotent behavior, the description provides all needed invocation context. It names accepted identifier forms, the data source, and access requirements, leaving no material gap for an agent to call the tool correctly.

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%, and the schema fully documents the single `id` parameter as accepting a volcano ID, VNUM, or name with examples. The description essentially restates this lookup flexibility without adding new semantic detail, so it does not meaningfully exceed the schema's baseline.

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?

The description opens with a specific verb and resource ('Get full detail for a single Alaska volcano') and enumerates concrete content fields: geology, composition, age, threat rating, and narrative. The word 'single' plus the lookup-by-ID/VNUM/name distinction separates it from sibling list/search tools like geodiva.geology.volcano_list and geodiva.geology.eruption_search.

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 description implies when to use the tool: when a user needs full detail for one volcano identified by ID, VNUM, or name. However, it never explicitly names alternatives such as volcano_list for browsing or eruption_search for eruption history, nor does it state conditions for not using this tool.

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