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

On top of annotations (destructiveHint=true, idempotentHint=false, openWorldHint=true), it discloses the key behavioral facts an agent could not infer: this re-sends an email to a third party, requires confirmation first, is throttled on an escalating cadence (60s then 24h), and is capped at 2 resends total.

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 dense sentences that lead with the action and scope, then the confirmation requirement, then the rate limits. No filler and no repetition of the title.

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 mutation with annotations and no output schema, the description covers actor scope, prerequisite lookup tool, user-confirmation gate, and rate-limit behavior. Nothing material is missing for correct invocation.

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 both parameters are already documented in the schema, making 3 the baseline. The description only restates the confirmation requirement and the origin of request_id, adding no new syntax or format detail beyond the schema.

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 a specific verb (resend) and resource (the notification email for an outgoing pending friend request), and narrows scope to YOUR OUTGOING requests identified by request_id. It also points to friend_requests_pending as the source of that id, which cleanly separates it from friend_request_send and friend_request_accept.

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 states the precondition (an existing outgoing pending request, id obtained from friend_requests_pending) and a required user-confirmation workflow before calling. It does not explicitly name an alternative tool or say when NOT to use this, but the throttle cap of 2 resends supplies a practical boundary.

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