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

Annotations already declare read-only, idempotent, non-destructive, and closed-world behavior. The description adds valuable context beyond that: the CDP fallback to document.cookie (which limits results to non-httpOnly cookies) and the specific cookie attributes returned.

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 compact sentences with no wasted words. The purpose is front-loaded, followed by fallback behavior and parameter hint, all of which earn their 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 read-only tool with full schema coverage, safety annotations, and no output schema, the description provides sufficient context: what it returns (cookie fields), how it retrieves them, fallback behavior, and parameter defaulting. Nothing critical for correct invocation 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%, so the schema already documents all parameters. The description adds a useful clarification that omitting pageId auto-selects the visible/active page, which is more specific than the schema's 'auto-picked when omitted'.

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 'Get' and resource 'cookies' with scope 'for a page on the device via CDP', and names the exact CDP method. It is clearly distinguishable from sibling devtools tools like android_devtools_capture_network or android_devtools_console_logs.

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 a use case ('useful for debugging auth/session state') but does not name alternatives or conditions when this tool should not be used. The parameter hint about pageId omission is more about parameter semantics than usage guidance.

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