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

Beyond the readOnlyHint and openWorldHint annotations, the description explains the meaning of each status value and gives expected timing behavior. This is valuable operational context that helps the agent interpret results and decide how to poll.

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 compact and front-loaded, starting with the primary purpose before explaining statuses and polling. Every sentence earns its place, with no filler or redundancy.

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 read-only status tool with no output schema, the description supplies all necessary operational details: status values, their meanings, expected timing, and polling guidance. An agent has enough information to call the tool and interpret the result correctly.

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 schema already fully describes fax_id as 'The fax_id returned by send_fax,' so the description adds little beyond reinforcing the link to send_fax. With 100% schema coverage, the baseline applies; no extra parameter semantics are needed.

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 identifies the tool as checking fax delivery status and explicitly ties it to faxes sent via send_fax. It distinguishes this tool from siblings because it is the only one focused on status checking for already-sent faxes.

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 gives concrete usage context: it is for faxes sent with send_fax, and it even advises polling every 30 seconds with expected delivery times. It does not explicitly name alternatives or state when not to use it, but the context is clear enough for an agent to select this tool appropriately.

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