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

With readOnlyHint: true provided in annotations, the description does not need to restate the read-only nature. It adds useful behavioral context by describing the chain as 'bounded' and requiring an exact event id, which implies deterministic expansion. It does not describe return format or pagination, but this is somewhat covered by annotations and the bounded nature. No contradictions found.

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 three sentences, but the first sentence 'Free linked-disaster helper' is vague and adds little value. The remaining sentences are efficient and clearly state the primary purpose and usage condition. Slight waste in the opening phrase prevents a 5.

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 the core behavior and usage condition, and with readOnlyHint and full parameter schema, the tool is well-specified. No output schema exists, but the description hints at the chain outcome. It is complete for a simple read-only helper, though mentioning the depth limit (already in schema) could add clarity.

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 the baseline is 3. The description reinforces that event_id must be exact and mentions supported packs, aligning with pack_id. It does not add significant new semantics beyond the schema, but the context of 'bounded chain' implicitly relates to depth. A 3 is appropriate since the schema carries the load.

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 action: 'Expands one exact disaster event id into a bounded related-event chain.' It specifies the resource (exact disaster event id) and scope (bounded chain). It also distinguishes from siblings by noting the requirement for an exact event id and listing supported packs, which differentiates it from search-based tools like search_disaster_links.

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 provides explicit usage guidance: 'Use this only when you already have an exact event id from a supported pack,' which sets a clear precondition and names the supported packs. However, it does not explicitly name alternative tools or say when not to use it, so it does not fully address the 'vs alternatives' aspect required for a 5.

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