new_page

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

Annotations only set readOnlyHint=false, so the description carries most of the burden. It says a tab is opened, which is consistent with the mutation annotation, but doesn't disclose whether the new page becomes the active target (relevant given sibling select_page), whether the tab persists, or whether it operates in the same browser context by default. Only the schema fills that in.

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 with the action front-loaded and no filler. The second sentence is vague ('otherwise') and could have been replaced with actual guidance.

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?

With four parameters, one required, and no output schema, the description should indicate what the agent gets back (e.g., a page handle usable with select_page) and how the new tab relates to existing ones. The schema covers the parameters well, but the interaction model is left implicit.

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 all four parameters are already documented, which sets the baseline at 3. The description adds only the default-URL notion, and it muddles rather than clarifies semantics by implying url is optional when the schema requires it.

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 new tab and load a URL.' This is clearly distinct from navigate_page (which navigates an existing page) and from select_page, though the description never names those siblings. Clear but not differentiated explicitly.

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?

'Use project URL if not specified otherwise' is a hint about the url argument, not a when-to-use rule; it also conflicts with the schema marking url required. Nothing tells the agent when to use this over navigate_page or select_page, or what happens to the previously active page.

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