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

No annotations are provided, so the description carries the burden of behavioral disclosure. It discloses the return shape (`{ closed, pageId }`) and reconciles the failure case (`closed:false if no such page`). However, it doesn't mention side effects like whether closing a page terminates the browser or affects other tabs, nor does it mention any permission or session requirements. A 3 is fair since it covers outcome but not potential side effects.

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?

Three sentences, compact and front-loaded with the core action in the first sentence. The CDP implementation detail, use case, source reference, and return shape are all packed efficiently. Minor redundancy between 'close' in the first sentence and 'clean up stale tabs' — but this adds context rather than waste. Very tight and effective.

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?

The tool is a simple close operation with 3 params, no output schema, and no nested objects. The description covers purpose, usage context, source of the key parameter, and return shape including the failure case. For a simple closure tool this is essentially complete — the only gap is side-effect disclosure (e.g., whether it crashes the browser context).

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 all three parameters (udid, pageId, socket). The description adds context for pageId ('from android_devtools_list_pages') which slightly augments the schema's phrasing. Baseline 3 is appropriate when the schema handles parameter documentation; the description's added value is marginal.

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 has a specific verb+resource: 'Close a debuggable tab/page on the device by pageId'. It clearly states the mechanism (CDP /json/close) and the use case ('clean up stale tabs'). It distinguishes from siblings like android_devtools_list_pages by explicitly referencing it as the source of pageId, and android_devtools_navigate is clearly a different operation.

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 gives clear when-to-use guidance: 'Use to clean up stale tabs that accumulate across sessions'. It also points to the prerequisite source of pageId via android_devtools_list_pages. It doesn't explicitly state when NOT to use it (e.g., which alternatives like navigate exist for closing pages), but the context is sufficiently clear.

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