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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. Because there is no output schema, the description adds genuine value by disclosing the returned status vocabulary and the conditional transmission-report link after delivery, though it omits error behavior for an unknown fax_id.

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 front-loaded sentence that states the resource first, then the status vocabulary, then the conditional report link. The parenthetical enumeration is long but every item earns its place by telling the agent which states to expect.

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?

With no output schema, the description carries the burden of describing return values and does so reasonably well (statuses plus report link). Somewhat thin on failure/edge behavior for an invalid fax_id and on the link's format, but sufficient for a simple idempotent read tool.

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?

There is a single parameter with 100% schema description coverage, so the schema already documents fax_id adequately. The description adds nothing about the parameter beyond what the schema states, which matches the baseline 3 for high coverage.

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?

States a specific verb (returns) and resource (fax status), and enumerates the six possible status values so an agent knows exactly what this tool reports. It is clearly distinct from the siblings send_fax, get_fax_price and create_upload_link, which perform write, pricing and file-handling tasks respectively.

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 contains no when-to-use, prerequisite, or alternative-selection guidance; it only says what the tool returns. The workflow hint (fax_id comes from send_fax) lives in the schema, not the description, so the description itself gives the agent no routing information.

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