query

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

No annotations are provided, so the description carries the full burden. It discloses that `contains` is case-insensitive and that a selector merely scopes that text search, and it documents the html-mode return (outerHTML), but it never states side effects, permissions, or that this is a non-mutating read — the safety profile an agent needs before invoking it.

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, front-loaded with the core extraction capability before the text-find mode and the list workflow. It is information-dense to the point of being run-on with stacked backticked fragments, but almost nothing is wasted.

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?

No output schema exists and there are 7 parameters with nested objects, so the description should carry more return-shape detail. It does describe the `contains` return (matching visible elements with selector path and ref), but says nothing about what `extract` or plain-text mode return, and never mentions tabId/spaceId targeting.

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%, so the schema already documents all seven parameters including `extract`'s field→sub-selector shape and '@attr' syntax. The description's example ({title:".name", link:"a@href"}) largely restates that, adding marginal value, so baseline 3 is right.

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 concrete verb+resource: extract structured data from the page by CSS selector, or find elements by text via `contains`. It explicitly contrasts itself with a named sibling ('use it instead of eval'), so an agent can separate it from eval, read_text, and snapshot without opening schemas.

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 gives concrete use cases (check 'is X on the page', read a status label, find a dropdown option) and names the alternative to avoid (eval), plus an operational workflow for lists (pass `html:true` first to inspect markup, then `extract`). It lacks explicit when-not-to-use guidance relative to read_text/snapshot, so it stops short of a 5.

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