List the shape of the browser's cookie jar, returning cookie names, domains, and attributes but never their values.
The shape of the cookie jar. Never a value.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral-disclosure burden. It does add one useful trait—'Never a value'—indicating it will not return cookie contents, but it omits authorization needs, mutation status, pagination, and return shape, leaving most behavioral context unstated.
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 extremely short and wastes no words, but its first sentence is metaphorical rather than action-oriented, and the caveat is not front-loaded. It is concise yet under-structured for reliable tool selection.
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?
Given an empty input schema, no annotations, and no output schema, the description must do all the explanatory work. It only states that the result is about the cookie jar's shape and excludes values, but it never says what the tool actually returns or when to invoke it, making the definition incomplete for a zero-parameter listing tool.
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?
The tool takes zero parameters, so there is no parameter information to document. Per the baseline for a parameterless tool, a 4 is appropriate; the description neither helps nor hurts because no parameters exist.
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 hints at returning cookie metadata rather than values, but it never states the action (e.g., 'list cookies') or what 'shape' concretely means. An agent can guess it is a non-destructive read of cookie structure, yet the purpose remains vague compared to a specific verb+resource statement.
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?
There is no guidance on when to use this tool versus alternatives such as cookie_delete or credential.list. The description provides no context, exclusions, or prerequisites, leaving selection entirely to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.