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

Goes well beyond the annotations: it discloses the operation is asynchronous and slow ('takes a few minutes'), that it returns an id immediately, that progress is tracked via app_status, that publish is a separate step via deploy_app, and that the user can watch the build through a link. Annotations only cover safety/open-world hints; this adds the latency and workflow behavior an agent needs.

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?

Front-loads the trigger and scope, then packs the async workflow and the sibling exclusion into a compact set of sentences. No filler; every clause adds actionable 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?

Despite an async, multi-step operation, the description fully covers initiation, immediate return, progress polling, and publishing, and an output schema already exists for return shape. Nothing an agent needs to call it correctly is missing.

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 all three parameters are documented in the schema, so the description adds little parameter-level meaning beyond echoing the 'idea' concept. Baseline 3 is appropriate when the schema carries the parameter detail.

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+resource ('build a working web (or mobile) app') with concrete example domains, and explicitly distinguishes itself from the sibling open_app_builder. An agent can tell what this does and what it is not without reading the schema.

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?

Gives the trigger condition ('when the user wants a working app built'), names the alternative tool and the condition that selects it ('to only open the builder with an idea, use open_app_builder'), and lays out the follow-on flow (app_status, then deploy_app). Explicit when/when-not/alternatives.

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