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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety bar is low. The description adds genuinely new context: the operation is 'Free' and its scope is explicitly bounded to structure, excluding text and field values. It still says nothing about cost/latency on large files or whether the PDF must be pre-uploaded.

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?

Front-loaded with the useful scope statement, but the second sentence redundantly re-lists nearly the same fields as the first (page count, sizes, rotations, encryption, form fields, annotations), padding the description without adding information.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile; the description supplies the remaining scope boundaries well. The one real gap is the unexplained artifact_id, which an agent must resolve before it can call the 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?

Only one required parameter with 0% schema description coverage, so the description carries the full burden — yet it merely restates the name ('Structural facts about artifact_id') without saying what an artifact_id is, how to obtain one, or that it is a UUID reference to an uploaded document.

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 (report/inspect) and resource (a PDF's structure) with an enumeration of exactly what is returned: page count, sizes, rotations, encryption, form fields, annotations. The closing 'No text, no field values' cleanly separates it from content-reading siblings such as read_form and verify_form.

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?

Gives clear selection context by contrasting structural facts with content extraction ('No text, no field values'), which implicitly routes content needs to other tools. It stops short of naming an explicit alternative (e.g. 'use read_form for field values') or stating prerequisites like needing a previously uploaded artifact.

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