fast_browser_open

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

With no annotations, the description carries the burden. It discloses that a browser session is initialized or reused, and a snapshot is stored. However, it does not explain what 'initialize' means, what happens on invalid URLs or sessionIds, browser type, or snapshot content. Some behavioral aspects are hinted but not fully transparent.

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 sentence that is front-loaded and contains no fluff. It covers the key actions efficiently. However, it could be slightly more structured by separating the URL opening from session management, but overall it is appropriately concise.

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 tool is relatively simple with only 2 parameters and no output schema. The description adequately explains the core function, but it lacks context about how the snapshot is used by sibling tools or what constitutes a 'session'. For a tool that initiates browser automation, it could provide more context about subsequent steps.

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 0%, so the description must add meaning. It mentions 'Open a URL' for the url parameter, which is clear but doesn't specify the URI format (covered by schema). For sessionId, it implies the parameter via 'initialize/reuse a browser session', but does not explicitly map sessionId to that behavior. The description provides minimal added value over the raw 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 the action (open a URL), the resource (URL), and additional actions (initialize/reuse session, store snapshot). It distinguishes itself from sibling tools like fast_browser_act and fast_browser_snapshot by being the entry point. However, the phrase 'initialize/reuse' could be more explicit about session management.

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. It does not specify that this is the first tool to call before using other browser tools, nor does it explain when to use a sessionId (e.g., existing session vs. new). Sibling tools exist for actions, diffs, etc., so usage context is missing.

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