open_url

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

The description adds meaningful behavior beyond the annotations: it navigates without raising the window, handles beforeunload with a default of dismiss, auto-accepts in lab mode for configured hosts, and explains how to override with 'accept', 'manual', or 'intent_leave=false'. This is substantial, non-contradictory context that an agent needs to predict side effects and page-unload behavior.

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 focused sentences place the core purpose first and then dive into the most nuanced behavioral mode. The beforeunload clause is dense but earns its place by clarifying a confusing default. Slight loss of a point because the phrasing is telegraphic and an agent might need to re-read the lab-auto-host clause.

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 core behavior and beforeunload modes are well covered, and the presence of an output schema means return value detail is unnecessary. But with 5 parameters, 0% schema coverage, and no mention of timeout or session_id, the definition is not fully complete. The description gives enough for successful navigation but leaves parameter semantics partially depend, on the schema defaults.

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 schema has no property descriptions (0% coverage), so the description carries the burden for parameter meaning. It clearly explains beforeunload and intent_leave semantics, and url/tab are evident from the purpose. However, it leaves timeout and session_id completely unexplained, so the agent still lacks the full parameter semantics for a 5-parameter 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 opens with a specific verb and resource: 'Navigate the current real-browser tab through CDP without raising its window.' This clearly distinguishes the tool from siblings like open_new_tab (new tab), cdp_command (raw CDP), and activate_tab (focus/window behavior). The 'current real-browser tab' wording makes the scope unambiguous and the mechanism CDP-specific.

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 usage for the current tab versus opening a new one, but it never explicitly says 'use open_new_tab for new tabs' or provides exclusions. It does give rich guidance for the beforeunload parameter (accept, manual, intent_leave=false), which is useful, but lacks explicit when-to-use vs. sibling tools. The phrase 'without raising its window' hints at current-tab navigation but does not name an alternative.

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