query

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

With no annotations, the description carries the full behavioral burden, and it does disclose the return shape (tag, id, classes, text, href, rect, visibility), which is genuinely useful. It omits whether the query is non-mutating, how it behaves on zero matches, whether it waits for dynamic content, and how the limit truncates results.

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?

A single dense sentence that front-loads the action and then lists the return fields. No filler.

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 usefully documents the returned fields, which is a meaningful contribution. Still missing are no-match behavior, wait semantics for dynamic DOM, and the tabId parameter's role, which leaves the agent guessing in this DOM-heavy 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 only 33% — selector and tabId have no schema descriptions. The description clarifies that selector is a CSS selector, which is the most important clarification, but tabId's meaning (active tab vs. specific tab) is left unexplained in both places.

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 and resource ('Query elements by CSS selector') and enumerates the returned fields, so the agent knows exactly what comes back. It does not, however, distinguish itself from nearby read-oriented siblings like snapshot, get_html, or evaluate.

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?

There is no guidance on when to use this tool rather than snapshot, get_html, or evaluate, and no exclusions or prerequisites. The agent must infer usage from the name alone.

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