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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds the scoping constraint (pending requests for the calling user), which is useful for selection but does not disclose additional behavioral aspects like pagination, ordering, or return format beyond what the output schema presumably covers.

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, tight sentence with no filler. It front-loads the verb and resource and clearly states the filtering condition, making it easy for an agent to parse quickly.

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 no parameters and an output schema present, the description is complete. It clearly defines the input scope and result semantics. Minor missing details like pagination limits could be added but are not critical given the tool's simplicity and the presence of an output schema.

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 has zero parameters and the description correctly avoids repeating schema information. Since there are no params to explain, a baseline of 4 is appropriate; the description provides no additional parameter details because none are needed.

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 states the verb 'List', the resource 'friend requests', and the specific scope: 'directed at the calling user that have not yet been accepted or declined.' This precisely distinguishes it from sibling tools like play_list_my_friends (which lists all friends) and accept/decline/cancel actions.

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 description implies usage by specifying the pending status and target user, but it does not explicitly state when to use this tool versus alternatives (e.g., play_list_my_friends, play_accept_friend_request). No when-not or alternative guidance is provided beyond the inherent scope.

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