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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description does not contradict them. It adds value beyond the annotations by disclosing the outcome vocabulary (working, delivered, failed), that failure includes a reason, and that refund state is tracked, which helps the agent anticipate the tool's observable behavior.

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 17-word sentence that front-loads the core purpose ('Delivery status and receipt') then packs the outcome states into the tail. Every word 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 low-complexity, single-parameter read tool with rich annotations and an output schema present, the description is nearly complete: it names the resource type, the outcome states, and refund context. The only notable gap is guidance on how this differs from the get_job sibling, which prevents a 5.

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 has 0% description coverage on job_id, so the description carries the burden. It partially compensates by clarifying that job_id refers to a send_fax job, linking it to send_fax's output. But it does not specify the expected format, provenance, or how to obtain the ID, so compensation is incomplete.

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 checks delivery status and receipt for a send_fax job, enumerating the specific states (working, delivered, failed) and the failure reason plus refund state. This is specific and actionable, but it does not explicitly differentiate itself from the get_job sibling, which likely covers generic job status, so it falls short of a 5.

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 phrase 'of a send_fax job' implies the usage context: call this after send_fax to check delivery. However, it does not explicitly state when to use this instead of get_job or get_batch, nor does it mention any exclusions or alternatives among the 26 siblings.

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