Fetch in browser session

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and network reach are covered structurally. The description adds two useful traits — the session is "stealthy" and options do not persist across calls — but says nothing about failure behavior for the 17 options (timeout, cloudflare solving, blocked domains) or what happens when the session is stale.

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 short sentences, front-loaded with the action and with zero filler. The brevity is efficient; the only cost is that the second sentence is doing very little work for a tool with 17 parameters.

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?

The output schema covers return values and annotations cover read-only/open-world, so those burdens are lifted. Still, for a 17-parameter tool with 2 required fields, the description should state the session-lifecycle constraint and the distinction from browser_fetch_once; "options apply only to this request" only partly covers that.

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 every parameter including wait, network_idle, pierce_shadow and extraction_type is already documented. The description adds no parameter meaning beyond "options apply only to this request", so the baseline 3 applies.

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 and resource ("Fetch a URL") and scopes it to an existing browser session, which separates it from browser_open. However it never names browser_fetch_once or browser_extract, so the sibling with the near-identical name is not disambiguated from the text alone.

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?

"In an open stealthy browser session" implies a prerequisite (session_id from browser_open, as the schema notes) and "Options apply only to this request" hints at per-call vs persistent state. There is no explicit when-to-use/when-not guidance against browser_fetch_once, browser_extract, or make_request.

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