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

The readOnlyHint and destructiveHint annotations already indicate a non-read-only, non-destructive write. The description adds useful scope context ('on the current page') and clarifies that it may overwrite an existing cookie, which is transparent about the behavior.

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 a single, concise sentence that fully captures the tool's purpose without extraneous detail. It is appropriately sized for a simple operation.

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?

There is no output schema, so no return value explanation is needed. The description adequately conveys the operation and scope, but does not mention potential error conditions or prerequisites, which are likely implied by the browser context.

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 100% with each parameter having a basic description (e.g., 'Cookie name', 'Cookie value'). The tool description does not add further meaning beyond the schema, so a baseline score 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?

The description clearly states the action (create or overwrite) and the resource (cookie on the current page). It distinguishes from sibling cookie operations like get, list, and delete by explicitly mentioning creation/overwrite.

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 does not mention when to use this tool versus alternatives such as browser_cookie_get or browser_cookie_delete. No explicit usage conditions or comparisons to sibling tools are provided.

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