browser_frame_inventory

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

With no annotations provided, the description carries the full disclosure burden. It truthfully lists what the tool returns (iframes, canvas rects, shadow root count, bodyRect) and indicates it runs 'inside the frame,' suggesting a read-only operation. It does not mention side effects, error behavior, or timeout handling, but for an inventory operation the output disclosure is sufficient.

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?

The description is two sentences, with the first sentence enumerating the exact output items and the second providing the use case. Every word earns its place, front-loading the essential information without any fluff.

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?

Given the absence of an output schema, the description compensates by enumerating key output fields (id, name, src, rect, bodyRect) and the count of shadow roots. It is adequate for an inventory tool, but it does not specify the exact shape of rectangles or potential failure modes, leaving minor gaps.

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?

The input schema covers both parameters with descriptions: frameSelector ('Chained iframe selector') and timeoutMs. The description adds no additional parameter-level meaning beyond reinforcing the 'inside the frame' context, which aligns with frameSelector. Since schema coverage is 100%, a baseline of 3 is appropriate.

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 uses a specific verb ('list') and identifies exact resources: child iframes, canvas elements, shadow root count, and bodyRect. It clearly distinguishes itself from sibling tools by framing the output as an inventory of frame internals, with a concrete use case (detecting nested iframes or canvas UI).

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 description states when to use the tool: 'Use to see if visible UI is in a nested iframe or canvas.' This provides clear context but does not explicitly name alternatives or exclusions. It implies a diagnostic role without comparing to sibling tools like browser_frame_probe or browser_snapshot_frame, so it falls short of a full 5.

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