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

With no annotations present, the description carries the full burden. It discloses key limitations: only non-HttpOnly cookies, only those visible to the current page origin, and that the result is 'NOT verified afterwards.' It also mentions it cannot touch HttpOnly cookies, which is exactly the kind of behavioral nuance an agent needs.

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 dense but front-loaded: it states the core action and scope first, then the crucial preference/alternative, then the return value. Every sentence earns its place; there is no fluff or repetition of schema content.

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 no output schema, the description covers the essential return shape, platform support, scope limits, and the reason to prefer a sibling. It also notes the verification gap, which is critical for correct use. Nothing an agent needs to call it correctly is missing.

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%, and every parameter (udid, pageId, socket, platformVersion) is already documented in the schema, including the fact that platformVersion is ignored. The description adds no parameter-level detail, so the baseline 3 applies.

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 opens with a specific verb and resource: 'Expire all NON-HttpOnly cookies visible to the current page origin' and adds the mechanism 'via document.cookie' plus platform scope. It explicitly distinguishes itself from webpage_clear_browsing_data by name, so an agent can tell them apart immediately.

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?

It gives an unambiguous when-to-use and when-not-to-use directive: 'PREFER webpage_clear_browsing_data' and explains why (reaches HttpOnly cookies, verifies result, clears other storage). It also clarifies this tool is for callers that specifically want document.cookie behavior, leaving no ambiguity about the intended context.

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