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

Annotations already mark this as a write operation (readOnlyHint=false, destructiveHint=false). The description adds useful workflow nuance: it is the final registration step after a browser PUT, used by the composer UI, and is marked advanced. It does not go into idempotency or validation, but the annotations reduce that burden.

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?

Two sentences with no filler: the first states the operation and pairing, the second gives the precise invocation condition. Everything earns its place.

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?

The description is complete enough for an agent to know when and why to call this tool, especially with the fully described schema and sibling names available. It could mention result or post-condition behavior, but the absence is not a serious gap for this workflow.

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%, so all parameters are already explained in the schema. The description adds no parameter-specific meaning beyond the workflow context, 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 uses a specific verb and resource ('Record an uploaded R2 object as a media file') and anchors it to a concrete workflow: the browser PUT paired with create_media_upload. This clearly distinguishes it from related siblings like create_media_upload, upload_media, and complete_multipart_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 gives an explicit trigger condition ('Use this when a presigned direct upload finished') and identifies its pairing with create_media_upload. It does not explicitly rule out alternatives like upload_media or complete_multipart_upload, but the direct-upload context is strong enough to guide selection.

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