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

Annotations already declare readOnlyHint=false, destructiveHint=true and openWorldHint=true, so the mutation/world profile is covered structurally. The description adds genuinely new behavioral context: the ticket's 5-minute validity window and the fact that it is issued by an internal widget rather than the agent. It does not, however, explain what a ticket grants or what happens on expiry.

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, zero filler, with the operational constraint (who calls it) and the key return trait (5-minute validity) both front-loaded.

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 shape need not be described; the description supplies the one non-schema fact an agent needs (don't invoke directly, validity window). Complete for a single-parameter, non-agent-facing 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?

Schema description coverage is 100% and the sole workspaceId parameter is fully documented in the schema, including scoping rules and the current-workspace default. The description adds no parameter-level meaning, so the baseline 3 is correct.

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?

Names a specific verb and resource (authorize storing one file in media storage, return a ticket) and identifies the exact caller (the upload box shown by open_upload_widget). This cleanly distinguishes it from siblings like upload_media and open_upload_widget.

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 to use it and where to go instead: 'Do not call this yourself; call open_upload_widget instead.' It also gives the invocation cadence (once per file) via the described caller. Nothing is left to inference.

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