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

Annotations already cover readOnlyHint=false, destructiveHint=false, and openWorldHint=false. The description adds non-obvious behavior the annotations cannot express: the ticket has a 5-minute validity window and is issued per-file. It does not describe failure modes or auth requirements, keeping it short of a 5.

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 short sentences: purpose, return/validity, and the routing exclusion. Front-loaded and every sentence carries distinct information with no repetition of the schema.

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. Combined with full schema coverage on the only parameter and explicit routing, an agent has everything needed to call it correctly or defer to open_upload_widget.

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% for the single workspaceId parameter, with rich guidance about defaults and cross-workspace id semantics, so the description correctly defers. It adds no parameter detail beyond the schema, which is the baseline-3 case.

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 (authorize storing a file, returning an upload ticket) and ties it to a named sibling mechanism (the upload box shown by open_upload_widget). An agent can distinguish it from get_upload_urls and upload_media without opening schemas.

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?

Explicitly states when-not: 'Do not call this yourself; call open_upload_widget instead.' It also specifies the call cadence ('once per file'), removing ambiguity about batching or looping.

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