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

Annotations already declare readOnlyHint=true, covering the safety profile. The description adds useful behavioral context by specifying the approval condition and the uniqueness of sensitive data, but it does not discuss pagination, ordering, or response shape. This is acceptable given the annotations but not deeply transparent.

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 tight sentences with no filler. The primary function is stated first, and the important uniqueness caveat is second. Every word earns its place.

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 simple read-only list operation with one optional parameter, the description covers what the tool returns conceptually (approved introductions with names and contact details) and the key scoping condition. It does not detail response structure, but the absence of an output schema and the simplicity of the tool make this 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?

There is only one optional parameter, api_key, and the schema describes it thoroughly, including when to pass it versus using the bearer token. Schema description coverage is 100%, so the description need not add parameter-level detail. The baseline of 3 applies.

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 ('List') with a clear resource (introductions) and a concrete inclusion criterion ('where both humans approved'). It also adds the unique property that this is 'the only place names and contact details ever appear,' which clearly differentiates it from sibling tools like get_candidates or get_invites.

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 statement 'This is the only place names and contact details ever appear' gives a strong reason to use this tool when contact information is needed. It does not explicitly name sibling alternatives or state when not to use it, but the uniqueness claim provides clear contextual routing.

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