arc_watch_element

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

No annotations are provided, so the description must disclose behavioral traits. It only mentions using MutationObserver, omitting details such as whether monitoring persists across page loads, performance impact, or how changes are retrieved (via arc_get_element_changes). The description lacks sufficient behavioral context for an AI agent.

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 a single concise sentence that directly states the tool's purpose. It is front-loaded with the key information and contains no unnecessary words.

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?

The description is too brief given the tool's complexity (4 parameters, nested options, no output schema). It does not explain the expected return value (e.g., watch_id), the lifecycle (start→get→stop), or any side effects. An agent lacks critical context to use this tool effectively in a workflow.

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 baseline is 3. The description does not add any additional meaning to the parameters beyond the schema's own descriptions (e.g., 'CSSセレクタ'). It provides no extra context for parameter usage or constraints.

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 clearly states the tool's purpose: 'Start monitoring DOM element changes using MutationObserver.' It uses a specific verb ('start monitoring') and identifies the resource ('DOM element changes') and method ('MutationObserver'). This effectively distinguishes it from siblings like arc_get_element_changes and arc_stop_watch_element.

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 provides no explicit usage guidelines. It does not indicate when to use this tool versus alternatives, such as prerequisites (e.g., a loaded page) or the typical workflow of start, get changes, and stop. Usage is only implied through the tool's name and purpose.

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