browser_fetch

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It discloses that the request inherits session/cookies, CORS constraints, the return contents (status, headers, parsed body), and that it appears in the browser_debug network log. This is substantial context, though it does not cover error handling, timeout behavior, or side effects of non-GET methods.

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 three sentences, front-loaded with the primary purpose, followed by key behavioral details. Every sentence adds value: purpose, session/CORS behavior, and return/logging info. No redundant words 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?

Given the tool has 5 parameters, no output schema, and no annotations, the description covers the essential usage context: authentication, CORS, return value, and integration with the debug log. It does not elaborate on error conditions or partial success, but the schema fills in parameter defaults. Overall, it is sufficiently complete for selection and invocation.

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 input schema covers 100% of parameters with descriptive field descriptions (e.g., 'auto-JSON-encoded if object', 'Response parse mode'). The tool description does not add meaning beyond the schema's parameter descriptions, so it earns the baseline score of 3 for this dimension.

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 'Execute an authenticated fetch() request inside the page context,' which clearly states the action and target. It distinguishes itself from sibling tools like browser_navigate (navigation) and browser_eval (script evaluation) by specifying it is a fetch request, not a navigation or UI interaction.

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 context for usage: it inherits the page's cookies and session, making it appropriate for authenticated requests. It also notes same-origin works automatically and cross-origin requires CORS, giving a practical condition. However, it does not explicitly name alternative tools or state when not to use it, so it lacks explicit exclusions.

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