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

Annotations are minimal (only a title), so the description carries the full burden. It discloses that it is not browser execution and that it checks HTML and SDK calls, implying a read-only static analysis. However, it does not explicitly state that it has no side effects, whether it requires authentication, or what the output format is. For a test tool, this is acceptable but not rich behavioral detail.

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 description is a single, well-structured sentence that front-loads the action, explains the method, and clarifies a key limitation. There is no fluff or redundancy; every clause adds value.

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 a tool with one parameter and no output schema, the description covers the purpose and method but omits what the result looks like (e.g., a report, pass/fail list). Since there is no output schema, the description should ideally indicate the return format to fully prepare an agent. This gap prevents a higher score.

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?

The schema covers the single parameter 'slug' with a description ('The app's URL slug'), and the tool description does not add any extra semantics beyond that. With 100% schema coverage, the baseline of 3 applies; the description adds no further parameter context.

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 states a specific verb ('Test an app'), identifies the resource, and explains the method (checking HTML and SDK calls). It also clarifies it is not browser execution, distinguishing it from browser_read/browser_shot and other apps_* tools. This gives an agent a clear sense of what the tool does and how it differs from siblings.

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?

The description implies usage for static testing without opening the app, but it does not explicitly name alternatives or state when to prefer this over apps_build, apps_buildstatus, or browser tools. The clarification 'this is not browser execution' hints at the boundary but does not provide explicit when-to-use/when-not-to-use guidance.

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