Open browser session

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

Beyond the annotations (readOnlyHint=false, openWorldHint=true, destructiveHint=true), the description discloses cancellation semantics, cleanup of late-created pages, session isolation, and that the browser stays warm. This is rich, non-obvious behavioral detail that helps an agent predict side effects and manage resources. No contradiction with annotations.

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?

Three sentences, each earning its place: the first states the core action and output, the second explains cancellation behavior, and the third sets performance expectations. Information is front-loaded and there is no filler or repetition of schema data.

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 output schema, the description covers the main behaviors: new session, snapshot return, cancellation cleanup, session isolation, and warm browser. The 'compact full snapshot' phrase is somewhat generic and does not specify the snapshot's structure, but combined with annotations the essential context is present.

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 coverage is 50%: storage_state is described in the schema, while url is not. The description adds some meaning to url by specifying 'HTTP(S) page' and implies session context, but it never mentions storage_state or its role. The schema description covers storage_state, so overall the agent can understand both parameters, but the tool description itself adds only partial compensation for the low schema coverage.

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 states a specific action ('Open an HTTP(S) page'), a specific resource ('in a new session'), and what the tool returns ('a compact full snapshot'). It is clear and unambiguous. However, it does not explicitly contrast with sibling tools like tab_navigate or tab_tabs, though 'new session' implicitly points to a distinction from operating on existing tabs.

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 provides clear contextual guidance: this tool opens a page in a new session, and cancellation cleans up the attempt without closing sibling sessions or the shared browser. This tells the agent the tool is appropriate for isolated, temporary page opens. It lacks explicit when-not-to-use instructions or named alternatives, but the context is strong.

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