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 that it reads visible text (not hidden/DOM) and is desktop-only, which is valuable. However, it does not mention return format, error behavior, or whether it waits for page load. For a read-only tool these gaps are moderate, hence a 3.

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 with zero fluff. The core action and scope are front-loaded, and the device exclusion is given immediately after the main purpose. Every word earns its place.

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 low-complexity read tool with fully documented parameters and no output schema, the description covers the essentials: what it does, when to use it, and how it differs from device-specific alternatives. Minor omissions like return format or load-wait behavior are acceptable given the simple nature of the operation.

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% — both pageId and selector are already documented in the schema, including the pageId source and selector omission rule. The description adds minimal new meaning (repeats 'by pageId'), so baseline 3 is appropriate.

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?

Clearly states the verb (read), resource (visible text from the desktop grid browser), and scope (one element or whole page). It explicitly differentiates from webpage_get_text by device type, and frames its primary use case ('ASSERT on what is actually on screen'), making its purpose unambiguous.

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?

Provides explicit when-to-use guidance ('This is how you ASSERT on what is actually on screen') and names the exact alternative for phone/tablet (webpage_get_text) with the parameter that selects it (udid). No confusion about when to choose this tool.

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