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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: data source (geodiva.avo.alaska.edu), no authentication required, public domain status, and support for negative/BCE years. These details exceed the structured annotations without contradicting them.

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?

Two sentences with no filler. The first sentence states the core purpose and parameters; the second covers returns and provenance. Information is front-loaded and every word 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?

The description covers all essential aspects for a search tool: how to query, what is returned, and data provenance. A minor gap is that it does not specify behavior when no parameters are provided (e.g., returns all eruptions), which could be ambiguous. However, given the output schema exists and annotations cover safety, this is a minor omission.

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 baseline is 3. The description goes beyond the schema by clarifying that volcano_id comes from volcano_list, explaining that date ranges accept years or ISO dates including BCE, and indicating that fields returned include name, narrative, and start/end dates. This adds useful linkage and format context, elevating it above 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 clearly states the tool's purpose: searching documented eruptions for an Alaska volcano via volcano_id, eruption_id, or date range. It specifies the resource and differentiates from sibling tools like volcano_list and volcano_detail by focusing on eruption records. The verb 'Search' and resource 'eruptions' are unambiguous.

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 usage by listing accepted query methods (volcano_id, eruption_id, date range), but does not explicitly state when to use this tool versus alternatives such as volcano_detail or volcano_list. It provides clear context for invocation but lacks explicit exclusions or a 'when not to use' note.

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