live_snapshot

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

With no annotations, the description carries the full burden. It discloses the prerequisite (side panel open and connected) and describes the output format (text tree). It does not explicitly state read-only behavior, but 'snapshot' implies no side effects. It omits error handling or limits, but these are less critical for a read operation.

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 sentence that efficiently packs the resource, format, use case, and prerequisite. It is informative without being verbose, and the main purpose is front-loaded.

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?

For a simple snapshot tool with no output schema, the description explains the output format, the target tab selection logic, and the prerequisite. This is sufficient for an agent to understand what to expect and when to call it.

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 has 100% description coverage for all three parameters, so the baseline is 3. The description does not add any extra meaning beyond what the schema already states, so it remains at the baseline.

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 specific verb+resource: it provides an ARIA snapshot of the side panel's target tab, described as a text tree of roles/names/values. It explicitly ties the purpose to finding selectors for live_run_step/add_step without a screenshot, clearly distinguishing it from visual screenshot tools.

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 identifies the primary use case (finding a selector without a screenshot) and states a prerequisite (side panel open and connected). It implies it is an alternative to screenshots but does not explicitly name alternatives or specify when not to use it, so it falls short of fully explicit guidance.

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