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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world behavior, so safety is covered. The description adds useful behavioral context by enumerating the returned hotline set and noting the ordering of the Veterans Crisis Line first.

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 front-loaded with the resource identity but then spends most of its length enumerating hotline names. The critical 'Use when someone is in crisis' guidance is buried near the end, and the list of specific hotlines may be more verbose than necessary for tool selection.

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 no output schema, the description usefully identifies the returned hotline directory and filtering options. It is complete enough for a simple, annotation-covered read tool, though it could clarify behavior when no filters are supplied.

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 coverage is 100%, so both optional parameters are already documented in the schema. The description repeats the audience and language filters but omits several enum values (transgender, youth_25_and_under, service_provider), adding little beyond the structured schema.

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 identifies the resource (crisis hotline directory) and scopes it as 'beyond 988,' then lists the returned hotlines. It is specific but does not distinguish itself from the sibling veteran_crisis_resources, so it stops short of a 5.

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?

It gives a clear usage trigger ('Use when someone is in crisis'), which is better than implied guidance. However, it offers no when-not guidance and does not mention the overlapping sibling veteran_crisis_resources, leaving the agent to infer which crisis tool to call.

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