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

Annotations only give the safety profile (readOnly=false, idempotent=true, destructive=false); the description adds the substantive behavior: where the asset lands (named project, project_id/same_project_as, else a new project), that no link needs opening, the returned asset_id/revision/open_url, the auth requirement, and the exact failure+recovery path per agent. That is rich disclosure beyond the structured fields.

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?

Usage is front-loaded and most content earns its place, but it is delivered as one sprawling run-on sentence with deeply nested parentheses, and the per-client sign-in instructions (/mcp, claude mcp login, codex mcp login) add bulk that is tangential to calling the tool.

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?

With no output schema, the description correctly compensates by describing the return values (asset_id, revision, open_url) and covers the auth requirement and failure mode. It is slightly undercut by naming parameters absent from the schema, which leaves a small ambiguity about what the call actually accepts.

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 100% for the single 'handle' parameter, so the baseline is 3. The description adds placement logic but does so by referencing 'project_id' and 'same_project_as', which do not exist in the provided schema — that mismatched parameter vocabulary can mislead an agent rather than clarify.

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: it saves a finished set straight into the user's appdesigns library, with no link to open and nothing to press. It names the upstream siblings (finish_project/update_project, create_design/update_design) that must precede it, so an agent can place it precisely in the workflow.

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 the triggering condition ('when the user is signed in and a set you made is ready ... once the previews look right') and names the exact prerequisite tools. It also states the when-not path: a call without sign-in fails and must be followed by an authentication step.

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