Page info

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description then adds genuinely new behavioral detail by enumerating what is actually collected, notably that the frame tree includes cross-origin iframes and that main-document security details are reported. It does not mention that the values are a point-in-time snapshot or how missing fields behave, keeping it below 5.

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?

One front-loaded sentence with a dense but purposeful field list; no filler, no restatement of the title. The most important identifiers (URL, title, load state) come first.

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 no output schema, the description must carry the return-shape burden and it does so by enumerating every reported field group. It is slightly incomplete on edge cases (fields absent on non-page targets, snapshot semantics), but an agent has enough to decide to call it.

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 100% and the single tabId parameter is fully documented in the schema, including the default-to-session-tab behavior and a pointer to tab_select. The description says nothing about parameters, which is acceptable given the schema does the work, so the baseline 3 applies.

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 names a specific verb ('Returns') and enumerates the exact metadata resource: URL, title, load state, language, viewport, scroll, document size, frame tree, security details. This clearly separates it from page_snapshot/page_read (content) and browser_status (browser-level). It stops short of a 5 because it never explicitly contrasts itself with those nearest siblings.

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?

No indication of when to call this versus page_snapshot, dom_inspect, or browser_status, and no prerequisites or exclusions. The agent must infer from the return-field list that this is a lightweight metadata probe rather than a content read.

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