open_sidepanel

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

With no annotations, the description carries the full burden. It discloses that the side panel opens in a new tab (a notable side effect) and that an accessibility snapshot is returned. However, it does not clarify whether the tab remains open, if permissions are needed, or any cleanup behavior, leaving some behavioral ambiguity.

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, front-loaded sentence that efficiently conveys the action and result. Every word contributes value with no redundancy or 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?

For a tool with no parameters and no output schema, the description covers the core behavior and return value. It could elaborate on the exact format of the accessibility snapshot or prerequisites, but given the tool's simplicity, the description is reasonably complete for an agent to select and invoke 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 tool has zero parameters, so the baseline for this dimension is 4. The description does not need to explain parameter meanings, and the schema trivially covers all parameters.

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 specific action ('Open') and resource ('extension side panel'), further constrained by 'in a new tab' and the return of an 'accessibility snapshot'. It naturally distinguishes itself from sibling tools like open_popup (opens popup) and snapshot (returns snapshot of current state).

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?

No explicit guidance is given for when to use this tool vs alternatives, nor are any prerequisites or exclusions mentioned. The description implies use when needing a side panel accessibility snapshot, but lacks explicit contextual direction or named alternatives.

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