open_url

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

With no annotations, the description carries the full behavioral burden. It usefully discloses the headless default and how to get a visible window, but says nothing about session persistence across sibling calls, whether existing pages are replaced, auth requirements, or side effects. No output schema exists, so return behavior is also undisclosed.

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 compact sentences with zero filler, and the key operational fact (headless by default) is front-loaded after the purpose statement. Slightly terse for a six-parameter tool, but nothing is wasted.

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 tool with no annotations and no output schema in a multi-tool browser session, the description omits what happens after navigation — whether the session persists for screenshot/close_browser, and what is returned. It covers the core act of opening a URL but leaves session lifecycle behavior to inference.

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 is already documented in the schema. The description repeats the headless default rather than adding new semantics (e.g., how settle interacts with lazy loading, or timeout behavior on failure). Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('Open a website in a controlled Chromium browser'), which is unambiguous about what the tool does. It does not explicitly differentiate itself from siblings like screenshot or close_browser, but as the obvious session entry point the distinction is reasonably clear.

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, no prerequisites, and no mention of the sibling tools (screenshot, read_screenshot, close_browser, browser_status) that share the browser session. Usage is only inferable from the browser-session context, not stated.

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