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

With no annotations, the description carries the full burden; it does disclose the two most surprising traits — it mutates the page by typing, and it withholds the code from the caller. It says nothing about timeout behavior (though a timeout_seconds param exists), what happens if no email arrives, or how 'matching page' is resolved among multiple tabs.

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 tight sentences, front-loaded with the action and ending on the critical caveat about the return value. Nothing is padded, though the brevity comes at the cost of the missing detail noted elsewhere.

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?

Five parameters at 20% coverage, no annotations, and no output schema: the description would need to explain the CDP target, page-matching inputs, and timeout semantics to be callable with confidence, and it explains none of them. An agent knows roughly what happens but not how to parameterize or interpret failure.

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 only 20% — four of five parameters (site, cdp_url, selector, timeout_seconds) have no schema description, and the description compensates for none of them. 'Matching page' vaguely gestures at site/selector but gives no meaning, and cdp_url — the sole required parameter — is never explained.

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 chain (wait for a code, type it into a page over CDP) and the resource (email code), which clearly separates it from read-only siblings like get_email_code. It stops short of naming which sibling to use instead, so differentiation is inferential rather than explicit.

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 clause 'The code is not returned' implicitly routes agents that need the code value to get_email_code or wait_for_email_code, and the CDP/page framing hints at the browser-driving context. But no sentence states when to prefer this over fill_code or wait_for_email_code, and no prerequisites (open CDP session, an email already triggered) are given.

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