page_open

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

With no annotations, the description carries the burden and adds key behavior: it returns a page_id, waits for the page to load, and clarifies that page_id must be reused. It could also mention timeouts or errors, but the critical operational behavior is disclosed.

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 purposeful sentences with no filler. The most important fact—navigation and the returned page_id—is front-loaded, and the example adds clarity without bloating the description.

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 two-parameter tool, the description provides enough to call it correctly: required inputs, return value, and how that return value connects to sibling tools. It does not cover failure modes or timeout behavior, but this is a minor gap given the tool's simplicity.

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%, so the description must explain the two parameters. It does so by explaining the relationship between session_id and URL and providing a concrete example. Some parameter-level detail is still implicit rather than explicit.

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 clearly identifies the action as navigating to a URL within an existing session, linking it to the sibling tools by returning a page_id used by subsequent page tools. It is specific and distinguishes page_open from session_create and other page tools.

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?

It states the context ('existing session') and gives conditional guidance to use page_a11y when iframes or shadow DOM are present. It could be more explicit about when not to use page_open, but the routing to an alternative is present.

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