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

Beyond the readOnlyHint/openWorldHint annotations the description adds the crucial non-obvious behavior: the tool surfaces a widget and then BLOCKS waiting for the user's follow-up message containing asset_ids. That interactive/asynchronous completion flow is real value the annotations don't convey. It does not contradict readOnlyHint (no server-side mutation).

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, front-loaded with the action, then the wait condition. The 'Then wait:' fragment is slightly terse but every sentence carries necessary information with no filler.

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?

For an interactive UI tool with annotations covering safety and no output schema, the description communicates the full call lifecycle (show widget -> user sends asset_ids). The only gap is the absence of any parameter detail, which the description leaves entirely to the schema.

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 coverage is only 50% (label documented, max_files not) and the description never mentions either parameter, so it adds no meaning about label text or the max_files/batch-size limit. With half the params undocumented in structured data, the description should have compensated but does not.

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 concrete action (show an inline upload widget) and its effect on the user (add local images), including a use-case hint ('ones they attached in chat'). It's distinguishable from sibling image tools, though it doesn't explicitly contrast with request_upload or show_images.

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?

Usage is implied by 'so the user can add local images (e.g. ones they attached in chat)', which tells the agent the triggering scenario. There is no explicit when-not or comparison against the similar siblings request_upload/show_images.

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