Wait for an email to arrive

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

With no annotations provided, the description carries full behavioral disclosure. It clearly states the timeout limit ('up to 55 seconds'), the return behavior ('Returns the message summary, or reports that nothing arrived'), and the critical nuance that a missing email is not an error. The retry semantic 'calling this again continues waiting' goes beyond what the schema conveys and is highly valuable for an agent.

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 four sentences, each serving a distinct purpose: action, usage context, return value, and error semantics. It is front-loaded with the core behavior and avoids redundant restatements of the title or schema. Every sentence 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 simple two-parameter tool with no output schema, this description is complete. It covers what the tool does, when to use it, what it returns, and how to interpret the empty result. An agent can invoke it correctly and know how to proceed on no result, which is the main uncertainty for a wait operation.

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 the baseline is 3. The description adds context that the timeout is used after signup/password reset flows, but it does not add significant meaning beyond the schema's parameter descriptions. The schema already documents address as 'The inbox address to watch' and timeout with default and maximum values.

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 tool's function: 'Wait for the next email to arrive at an inbox, up to 55 seconds.' The verb 'wait' and resource 'email at an inbox' make the action unambiguous, and the 'arrive' distinction separates it from siblings like list_messages and read_message that handle existing messages. The signup/password reset context reinforces the specific scenario.

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 when to use the tool: 'Use this straight after triggering a signup or password reset.' It also explains retry behavior with 'calling this again continues waiting.' However, it does not mention alternatives or when not to use it, such as when the email may already have arrived and list_messages would be appropriate, so it stops short of full exclusions.

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