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

The readOnlyHint annotation is true, so the description does not need to declare safety. It adds context about the 'bounded related-event chain' and the requirement of an exact event ID, which is useful. However, it does not describe behavior like cross-type linking, depth semantics, or output format. Given the annotation covers the read-only nature, the description provides adequate but not rich additional context.

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, front-loaded with the purpose 'Free linked-disaster helper' and immediately states the core functionality and usage condition. Every sentence earns its place, with no fluff or repetition.

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 the tool's complexity (5 params, one required) and the absence of an output schema, the description provides enough context to select and invoke the tool correctly. It explains the input requirement and the scope of results. However, it doesn't explicitly describe what the output looks like, but the description and schema cover the essential usage semantics, making it largely complete.

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?

The input schema has 100% description coverage for all five parameters, so the schema already explains each parameter well. The description adds no extra parameter-level detail beyond what the schema provides, such as the meaning of 'depth' or 'cross_type_only'. Therefore, the baseline score of 3 is appropriate.

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 uses a specific verb+resource: 'Expands one exact disaster event id into a bounded related-event chain.' This clearly states the tool's function and scope, distinguishing it from search or catalog tools. It also specifies the exact input requirement, making the purpose 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 explicitly says 'Use this only when you already have an exact event id from a supported pack,' providing clear when-to-use guidance. It implies that this tool is not for searching or exploring without an exact ID, though it does not name specific alternative tools. The exclusion is clear enough for an agent to make a correct choice.

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