Snapshot elements

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

Even though annotations already declare readOnly/openWorld/idempotent/non-destructive, the description adds valuable behavioral details: refs are replaced by each snapshot, stale refs produce stale_ref, iframe and shadow-root contents are not listed, and find narrows without renumbering. No contradiction with annotations.

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 dense but efficient: it front-loads the output format, then covers staleness, filtering, inaccessible frame content, and alternative tools in four information-rich sentences. No filler or repeated schema text.

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 adequately explains return value format, ref behavior, failure modes, iframe limitations, and parameter subtleties. It also situates the tool among siblings. Nothing essential is missing for an agent to select and invoke it correctly.

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 input schema already documents find, limit, session_id, and interactive_only in detail. The description adds framing like 'find narrows the list without renumbering', but this largely reinforces rather than extends the schema. Baseline 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 resource ('visible interactive elements... and headings of the active tab'), and specifies the exact output format as '@N role "name"' lines. It also distinguishes itself from sibling tools like surfsky_read and surfsky_screenshot by saying what this tool is for versus those.

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 explicitly says when to take a new snapshot (after navigation, tab switch, or changed:false), warns that acting on old refs fails with stale_ref, and points to alternatives for text and visuals. It gives clear guidance on when to use this tool versus siblings.

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