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

With only readOnlyHint=false in annotations, the description carries the behavioral burden and does well: it states the request carries no content, grants no permission, and explains idempotent retry behavior with denial retention for 24 hours. This adds meaningful behavior beyond the annotations, though it does not explain how 'opted-in' is determined.

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 sentences carry the action, exclusions, and retry behavior with no filler. The primary purpose is front-loaded and every clause earns its place.

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 single-parameter tool with an output schema and a minimal annotation set, the description covers the key behavioral nuance: no content, no permissions, and 24-hour retained retries. It leaves some context about recipient eligibility implicit, but not enough to block 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 0%, so the description must compensate. It adds the key semantic that recipient_id refers to an opted-in recipient, but it never explicitly maps the concept to the parameter name or discusses the ID format, which the schema already handles via pattern.

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 and resource: requesting that an opted-in recipient 'allow your mailbox.' It also sharpens the purpose by explicitly excluding message/task content and permission-granting, which separates it from send_task and allow_sender, though it does not name sibling tools directly.

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 the tool is only for opted-in recipients and that it is not for sending content or granting permissions, but it never states when to choose this tool over siblings like respond_connection_request or list_connection_requests. The usage context is inferable but not explicit.

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