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

readOnlyHint=true already establishes this is a safe, non-mutating call, so the bar is lower. The description usefully adds that it is a static, argument-free retrieval of specific emergency contacts, though it does not describe the response shape (e.g., how numbers are returned).

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?

Three tightly front-loaded lines: role marker, what it returns, when to use, and a call example. Every sentence earns its place with no filler.

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?

For a zero-parameter static resource lookup with no output schema, the description supplies everything needed: the returned resources, the trigger condition, and a concrete invocation example.

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?

Zero parameters, so the baseline is 4. The example call get_crisis_resources({}) reinforces that no arguments are needed, leaving nothing ambiguous for the agent.

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?

States a specific verb and resource ('Returns 911, the 988 ... Lifeline and the Crisis Text Line') and names the audience ('a child or teen in danger now'). It is clearly distinguishable from sibling tools like search_care_resources or get_availability, which serve non-emergency lookups.

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?

Gives an explicit trigger ('Any mention of self-harm, suicidal thoughts, or someone in immediate danger') and positions itself as 'Step 1 of crisis', so the agent knows both when to call it and that it precedes other crisis handling.

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