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

The annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, covering the safety profile fully. The description adds no behavioral context beyond what the annotations provide: it does not mention pagination, ordering, result limits, permissions, or any other operational trait. With annotations doing the heavy lifting and no extra disclosure, this is a minimal score.

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 short sentences with no waste. It front-loads the usage scenario and then states the operation, and the included example is compact and useful rather than redundant.

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-list tool with one fully documented parameter, rich annotations, and an output schema, the description covers when to invoke it and what it does. It does not explicitly clarify how it relates to sibling tools like relationships.types.list, but no critical invocation information is missing.

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 single parameter contact_id is fully documented in the schema as 'The contact's API id.' The description does not add any format, constraint, or meaning beyond that baseline, so a 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 states a specific verb and resource: it lists a contact's relationships to other contacts. This clearly distinguishes it from siblings like relationships.create, relationships.delete, and relationships.types.list, which handle creation, deletion, and relationship types rather than a contact's own relationships.

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 an explicit usage trigger with a concrete example: 'When the user asks how someone is connected to others, like "how does Sarah know James?"'. However, it does not name alternatives (e.g., relationships.types.list) or state when not to use this tool, so it falls short of a full 5.

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