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

No annotations are provided, so the description carries the full burden. It discloses the 100,000 character output cap, the truncation notice appended at the limit, and the auto-page-selection behavior. For element selection it notes it returns null when no match. These are useful behavioral traits beyond the schema.

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?

Two sentences, tightly written with zero filler. Every clause carries informative value: retrieval mechanism (CDP), element-targeting capability, output cap with truncation notice, and auto-selection behavior. Front-loaded with the core purpose.

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?

Given there's no output schema, the description appropriately notes the output cap and truncation behavior, giving some sense of what to expect on return. The tool is moderately complex (4 params), and while no return-format specifics are given beyond cap/truncation, the behavior is adequately conveyed for an HTML-fetching tool.

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%, so the schema documents all four parameters. The description adds clarity on pageId auto-selection and selector returning outerHTML of first match or null, which enriches some params. However, the description largely restates what the schema already conveys for most parameters.

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 clearly states the tool gets the outer HTML of a page or CSS-selector-matched element via CDP, with a specific verb+resource. It doesn't explicitly distinguish from siblings like android_devtools_elements or device_page_source, but the scope (page or element outer HTML on device via CDP) is clear enough.

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 context on when to use it (via CDP for page/element HTML) and explains the pageId auto-selection behavior. However, it doesn't explicitly state when-not-to-use or name alternatives such as device_page_source or android_devtools_elements, though the distinction is reasonably implied.

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