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

With no annotations provided, the description fully explains behavior: what each status means, what happens on failed deliveries, that queued means retry later, and that message delivery to the poster only occurs after link click. This gives the agent enough behavioral context to act safely and accurately.

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 dense but every clause adds value: scoping, usage trigger, all four status meanings, and the limitation about click tracking. It is front-loaded with the core purpose and keeps related details compact.

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?

Despite having no output schema, the description effectively documents the important output semantics: statuses, failed reasons, and retry guidance. The single parameter is fully described, and the tool's limitation is stated, so an agent can handle a user's complaint end-to-end.

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 100%: status_key is already described as 'The status_key from a send_message result.' The description restates this and references how it is used, adding minor reinforcing context but no significant new parameter meaning 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 states a very specific operation: checking the delivery status of a confirmation email by status_key, and it is clearly distinct from all siblings such as send_message and create_post. It also clarifies what it does NOT report (whether the user clicked the link), removing ambiguity.

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 explicitly says to use this tool 'when the user says they have not received the confirmation email.' It also gives conditional follow-ups per status (e.g., wait for queued, call send_message again on failed), and explicitly excludes checking link clicks from this tool's responsibility.

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