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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, non-idempotent), so the bar is lower. The description adds genuinely new behavior: the ticket is short-lived, and it exists only to serve a widget session, which explains the non-idempotency and tells the agent the artifact is ephemeral.

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 short sentences, both front-loaded with the essential facts (what is returned, who calls it) and zero filler. Nothing could be removed without losing information.

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-value documentation is not required, and the tool has one required parameter with full schema coverage. The description conveys the key constraint (widget-only, short-lived) but omits any ticket lifetime or reuse detail that would make it fully self-contained.

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 single session_id parameter already documents that it comes from open_media_uploader. The description adds no further meaning about the parameter, 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 names a specific verb (returns) and resource (a short-lived upload ticket) and scopes it to a media uploader widget session, which separates it from siblings such as open_media_uploader and upload_media. It stops short of explicitly contrasting itself with those siblings, but an agent can tell what the tool produces.

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?

"Called by the widget itself" implicitly signals that an agent should not normally invoke this directly, which is useful routing context. However, it never states when an agent *should* use it versus open_media_uploader or upload_media, nor does it issue an explicit do-not-call directive, so the guidance remains implied.

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