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

Annotations already declare readOnlyHint=true. The description adds meaningful behavior beyond that: it scopes results to the user's own phone and only to texts that have not yet gone out, and discloses that each result includes the task_id needed for cancellation. This goes beyond a generic read-only list.

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?

A single well-structured sentence that front-loads the main action, then adds the critical scope condition and the most useful output field. No wasted words 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 zero-parameter read-only list tool, the description is complete: it states what is listed, to whom the texts belong, their status, and the key output element (task_id). No separate output schema exists, but the description covers what an agent needs.

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?

The tool has zero parameters, and schema description coverage is 100%, so there is no parameter meaning for the description to add. The baseline of 4 applies because no parameter documentation gap exists.

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 specific verb and resource: 'List the texts scheduled to be sent to the user's own phone'. It adds precise scope ('that have not gone out yet') and the key output detail ('task_id needed to cancel each one'), clearly distinguishing this from the sibling cancel_scheduled_text.

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 makes the context clear: use this to see pending scheduled texts with their cancellation IDs. It implies the workflow of listing then cancelling via the task_id, but it does not explicitly name cancel_scheduled_text as the alternative.

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