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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds value by explaining MMI scale, clamping behavior, and output fields (magnitude, depth, etc.), which go beyond what annotations provide.

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. It front-loads the source and purpose, then provides parameter guidance and output details. Every sentence contributes meaningful information.

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?

Given there is no output schema, the description fully covers the return fields (magnitude, depth, locality, felt intensity, coordinates) and ordering (newest first). It addresses the core query parameters and their behavior. For a read-only query tool, this is complete and self-sufficient.

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%, but the description adds significant context: it explains the MMI scale (e.g., '3 ≈ widely felt, 5 ≈ damaging'), specifies defaults (limit default 15, min_mmi default 3), mentions clamping for out-of-range values, and clarifies that -1 returns all quakes. This enriches the schema and helps the agent choose correct values.

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 it returns recent New Zealand earthquakes from GeoNet, filtered by MMI. It specifies the source (GNS Science), the filter parameter (MMI), and the output fields, making the purpose unambiguous and distinguishing it from sibling tools like 'get_quake' or 'volcano_alerts'.

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 tells when to use it (to get recent quakes filtered by MMI) and mentions it is 'Keyless', implying no authentication. It provides context on MMI thresholds. However, it does not explicitly state when not to use it or name alternatives, though sibling tool names provide implicit differentiation.

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