List page elements

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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the bar is lower. The description still adds real behavioral context beyond them: refs persist while an element remains on the page, which explains the non-idempotent listing behavior flagged by idempotentHint=false. It does not mention limits or truncation on very large pages.

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 sentences, both front-loaded: the first leads with what is listed and what each entry contains; the second carries the ref-stability caveat. Every clause earns its place with no redundancy.

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?

There is no output schema, so the description correctly carries the full burden of describing the return shape (ref, role, accessible name, value/state, bounding box in CSS pixels). It omits the 'scope' parameter and any behavior for very large pages, but is otherwise complete for a single-optional-param read tool.

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% and the single 'scope' enum is fully documented in the schema itself (page vs viewport). The description adds no information about the parameter, so the baseline of 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?

States a specific verb ('list') and resource ('interactive elements ... and headings in the recorded tab'), and enumerates the element kinds and the exact fields returned. An agent can distinguish it from screenshot (visual capture) and from click/type (which consume the refs this tool emits).

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 phrase 'each with a ref to pass to click/type/scroll/wait_for' makes the workflow role explicit: call this to obtain refs for the interaction tools. However, it never states when NOT to use it (e.g. versus screenshot for visual inspection) or any prerequisite about recording state.

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