ensure_tab

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

With no annotations provided, the description carries full burden for behavioral disclosure. It only hints at 'openOrReuseTab' semantics but does not explain what happens when a tab already exists, whether it switches focus, creates a new tab, modifies existing tabs, or handles timeouts. This is a significant gap for a tool that likely performs navigation and tab management.

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 very brief and front-loaded with an example call, which is good. However, the inclusion of an internal implementation reference ('借鉴 ego-lite 的 browser.openOrReuseTab') adds noise without clarifying behavior for the agent. It earns a middle score because it is short but sacrifices useful information for a niche comment.

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 has two parameters, no output schema, and no annotations, yet the description explains almost nothing. It does not mention return values, side effects, or how it interacts with tab state (e.g., whether it can close other tabs). For a navigation-like tool that likely has side effects, this is severely incomplete, especially compared to richer sibling tools like `navigate` or `new_tab`.

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%, and the description does not elaborate on the meaning of `url` or `timeout`. The URL parameter is obvious, but `timeout` semantics (units, default, what it applies to) are entirely undocumented. With two parameters and zero schema coverage, the description should compensate but does not.

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 uses the verb 'ensure' with a URL resource, indicating the tool guarantees a tab exists at the given URL. However, it does not explicitly distinguish itself from siblings like `new_tab` or `ensure_real_tab`, relying on the reference to ego-lite's `openOrReuseTab` to suggest reuse-first behavior.

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 reuse-first navigation and notes that callers don't need to pass `reuse=True`, but it provides no explicit guidance on when to use this over `new_tab`, `switch_tab`, or `navigate`. It does not state when not to use it or name alternatives directly.

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