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

The annotations already declare this as read-only, idempotent, non-destructive, and closed-world. The description adds useful behavioral context beyond those annotations, including cost ('Free'), the returned status fields, and the resume workflow.

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?

The description is two tight sentences with no wasted language, front-loading cost and returned fields before the resume workflow. Every sentence contributes directly to correct invocation.

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?

There is no output schema, so the description must explain return values; it does so by enumerating state, completedParts, missingParts, and bytesReceived. For a one-parameter status tool, that is complete enough to support the resume workflow it describes.

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 100%, and fileId is already documented as coming from create_multipart_upload. The description references create_multipart_upload URLs but does not add meaningful semantics for the single parameter beyond the schema.

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 states the specific resource and returned information: state, completedParts, missingParts, and bytesReceived for a multipart upload. It also distinguishes the tool's role by tying it to resuming interrupted uploads and naming create_multipart_upload and complete_upload.

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?

It explicitly scopes usage to resuming an interrupted upload and gives the next steps: PUT only missing parts using the same URLs then call complete_upload. It does not state when not to use this tool or explicitly contrast it with abort_upload.

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