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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety and repeatability profile is fully covered. The description adds only that measurements are in millimeters and that DFM warnings/process fits are included, which is modest added context. It says nothing about error behavior for an unknown or stale part_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?

One tight, front-loaded sentence with no filler; every listed item is substantive. It loses a point only because the fragment form omits the verb, making the sentence slightly less self-contained than it could be at the same length.

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 simple one-parameter read tool, the structured fields carry most of the load: annotations cover the safety profile, the schema documents the ID, and an output schema exists so return values need not be restated. The description is therefore largely sufficient, with the only real gap being the absent statement of when this tool should be chosen over its upload/URL siblings.

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, and the schema already explains that part_id is a 'prt_...' value returned by upload_part or get_upload_url. The description contributes no additional parameter meaning, so the baseline of 3 applies.

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 enumerates the returned payload (status, geometry in mm, suggested units, DFM warnings, fit processes) but never states the action or that it is a lookup by part_id. The resource ('part') is identifiable from the name, yet the description alone reads as a field list rather than a verb+resource statement, and it makes no attempt to distinguish itself from siblings like upload_part, get_upload_url, or get_order.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternative tools. An agent must infer from the name and the schema's part_id note (that IDs come from upload_part or get_upload_url) that this is the follow-up read after an upload, which is the kind of routing the description should state explicitly.

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