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

With no annotations, the description carries the full burden of behavioral disclosure. It transparently explains the fallback behavior to document.cookie (non-httpOnly only) when the CDP call is unavailable, which is a significant behavioral trait. It also describes auto-picking behavior for pageId. It does not mention error cases or permissions, but for a simple getter, this is adequate.

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 concise, consisting of three sentences that each serve a purpose: stating the action and fields, describing the fallback, and giving parameter guidance. It is front-loaded with the core purpose and avoids any redundant or extraneous information.

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 simple cookie-getter tool with no annotations and no output schema, the description is remarkably complete. It specifies the mechanism, lists the returned cookie fields, explains the fallback behavior and its limitation, and provides auto-picking guidance for pageId. The schema covers the parameter details, so the description fills the remaining gaps effectively.

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%, with rich descriptions for udid, pageId, and platformVersion. The tool description adds overall context but does not provide additional parameter-specific semantics beyond what the schema already provides. The pageId behavior is more detailed in the schema than in the description, so the description adds marginal value here.

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's function: getting cookies for a Safari page on an iOS device via the Web Inspector (Page.getCookies). It lists the specific cookie fields included and differentiates it from other cookie tools by the iOS Safari platform and CDP mechanism.

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 provides clear usage context, noting it is useful for debugging auth/session state and explaining the fallback to document.cookie. It gives explicit guidance on the pageId parameter (omit to auto-pick the active page). However, it does not explicitly mention when not to use this tool or name alternative tools for other platforms.

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