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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds concrete behavioral context beyond them: the possible status values, that error text is returned on failure, that a download URL appears only when ready, and that the call is free (cost signal not in any structured field).

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?

Three compact sentences, all front-loaded: purpose/provenance first, return values second, cost note last. No filler or repetition of the name.

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 does the work of describing the return payload (status enum, error text, download URL), which is well covered. Minor gap: no guidance on polling cadence or what to do while status is queued/running.

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 0% for the single jobId parameter, so the description must carry the burden. It provides indirect meaning by stating the job originates from pdf_merge/pdf_split/pdf_compress, implying the ID is the handle returned by those tools, but it never states format or how to obtain the value explicitly.

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 and resource ('Check the status of an asynchronous PDFLean job') and explicitly ties it to the sibling producer tools pdf_merge, pdf_split and pdf_compress. An agent can distinguish it from other pdf_* siblings without opening a schema.

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?

Clearly states the context in which the tool applies: after starting an async job via one of three named sibling tools. It does not state explicit exclusions (e.g. 'do not call for synchronous tools'), but the scope is unambiguous.

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