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

The description discloses behavior well beyond the annotations: files are rendered by the appdesigns editor in the user's browser (the same pixels its Export saves), open_url produces them, and get_export with the returned export_id yields a download command. It also spells out the auth requirement in detail for asset_id (sign-in via /mcp, `claude mcp login`, or `codex mcp login`) versus no sign-in for handle. This is rich, actionable context for a non-idempotent operation.

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?

The content is front-loaded with the primary use case, but it is delivered as one dense paragraph of nested parentheticals, which makes the open_url/get_export workflow hard to parse. The information is mostly justified by the tool's multi-step nature, yet the structure could be split into clearer sentences without losing content.

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?

There is no output schema, so the description carries the burden of explaining the return flow, and it does so by pointing to open_url (generation) and get_export (download command). Auth requirements and the two input paths are covered. The one gap is that it never explicitly states what export_asset itself returns (e.g., an export_id/URL) beyond implying it through the follow-up call.

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 the schema already documents format, handle, and asset_id, including the enum and the handle/asset_id trade-off. The description reinforces the meaning of asset_id (something saved) and handle (something made in-conversation), but adds little syntax or format detail beyond what the schema provides, so the baseline 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 and resource: it exports the finished files (a PNG per screen, an MP4 for looping screens) of a saved asset or an in-conversation handle. It distinguishes itself from the get_export sibling by describing the two-step flow where open_url generates the files and get_export downloads them. The core purpose is clear, though it is buried inside a long narrative sentence rather than stated up front.

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 ("when the user wants the finished files... to upload to App Store Connect or the Play Console") and clearly separates the two input modes: asset_id for something saved vs handle for something made in-conversation and not yet saved. It does not name an explicit alternative tool to avoid, but the asset_id/handle routing is precise enough to select the right mode.

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