session_new_page

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

With no annotations, the description carries the behavioral burden. It discloses key behaviors: opens a new tab, makes it active, returns a page id, and persists tabs across calls and clients. This goes beyond the schema and gives the agent a clear model of the tool's effect. It could mention more about cleanup or session boundaries, but it is transparent for the operation it describes.

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 no filler. The action is front-loaded, the return value is stated, and the persistence behavior is explained in the second sentence to justify when to use it. Every sentence earns its place.

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 zero-parameter tool with an output schema, the description is complete: it explains the action, the side effect, the return type, and the recommended usage pattern. The sibling context and persistence rationale give the agent enough to call it appropriately without further investigation.

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 tool has zero parameters, so the baseline is 4. The description appropriately does not invent parameter details, and there is nothing additional to explain about inputs. The return value is mentioned, which is useful context.

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 make it the active one.' It clearly distinguishes itself from sibling tools like session_list_pages, session_select_page, and session_close_page by describing creation of a new page rather than listing, selecting, or closing one.

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?

Provides clear context for when to use the tool: when you want to keep one page while working on another, since tabs persist across calls and clients. It does not explicitly name alternative tools or state when not to use it, but the guidance is sufficient for most agents.

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