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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds useful domain context by defining what counts as a friend, but it does not disclose ordering, pagination, or rate-limit behavior beyond the structured fields.

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 a single concise phrase with no filler, and the core definition is front-loaded. It is appropriately sized, though it reads as a fragment rather than a complete sentence.

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, read-only list operation with an output schema and rich annotations, the description supplies the one piece of domain meaning not covered elsewhere: who counts as a friend. Return values are handled by the output schema and safety by annotations, so the remaining gap is mostly usage guidance rather than missing invocation-critical information.

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?

The tool takes zero parameters, so there are no parameter semantics to explain. The empty schema and 100% schema coverage mean the baseline score of 4 is appropriate for a parameterless operation.

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 names the resource (friends) and defines it as people who exchanged a friend code, which clarifies the domain beyond the tool name. However, it does not explicitly state the list operation in the description itself and offers no sibling differentiation against alternatives like find_people or list_follow_requests.

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?

There is no guidance about when to use this tool versus alternatives such as find_people, list_follow_requests, or pling_friend. Usage is only implied by the tool name, and no exclusions or prerequisites are mentioned.

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