browser_fetch

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

With no annotations, the description carries the full burden. It discloses that the request runs fetch() in the page context, inheriting cookies and auth tokens, and that it returns the response body. It doesn't mention potential CORS restrictions, redirect handling, or error behavior, but the core mechanism is transparent enough for basic understanding.

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?

Three concise sentences that immediately convey what the tool does, how it works, and what it returns. Zero waste, well-structured.

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 fetch tool with full schema coverage and no output schema, the description is reasonably complete. It covers the execution model (fetch in page context, auth inheritance) and return value. It lacks discussion of edge cases like tab-not-found or CORS, but these are not critical for core usage.

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%, so parameters are already well-documented. The description adds minimal parameter-specific insight beyond noting that the tab is matched by domain, which aligns with the 'tab' parameter's existing description. It doesn't add syntax or format details beyond the schema.

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 it makes authenticated HTTP requests through a browser tab's session, using fetch() inside the page context and inheriting cookies/auth tokens. This distinguishes it from a plain HTTP request tool and specifies the resource (browser session) and action (fetch).

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 implies the primary use case—accessing resources with the logged-in user's session and cookies—by explicitly mentioning 'authenticated' and 'inheriting all cookies and auth tokens.' However, it does not explicitly name alternatives like browser_fetch_auth or state when not to use this tool, 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.