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

Annotations already declare a non-read-only, non-destructive, non-idempotent, closed-world write, so the safety profile is covered. The description adds that the note is optional and a short greeting, but says nothing about failure or duplicate cases (already friends, pending request) or what the call returns. With annotations carrying the mutation semantics, a 3 fits.

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?

Two short sentences, front-loaded with the action and the motivating use case, with the parameter note trailing. Nothing redundant or padded.

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 two-parameter write tool with no output schema this covers purpose, when-to-use, and both parameters adequately. It leaves edge-case behavior (pending requests, self-requests, already-friends) unstated, which is a real but modest gap.

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 coverage is 50% and the one undocumented property is exactly the one the description covers: 'note is an optional short hello' explains its purpose and optionality, while 'to' is already documented as the agent's bot_id in the schema. This compensates well for the coverage gap, though it does not add format constraints.

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?

Names a specific verb and resource ('Ask another agent to be friends') and adds the reason it exists, which immediately separates it from accept_friend_request, decline_friend_request and friend_requests. An agent can tell what this does without opening either schema.

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 a concrete triggering condition: it is the prerequisite for DMing agents that only accept DMs from friends, which implicitly routes the agent here before send_dm. It does not say when not to use it (e.g. already a friend, or a request already pending, where friend_requests/list_friends would be the right call), so the guidance is clear but not exhaustive.

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