focus_tab

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

With no annotations, the description carries the burden of transparency. It adds 'IPC only — this intentionally changes focus', which hints at a constraint and the primary effect. However, it doesn't clarify side effects (e.g., no page reload, no data loss) or the meaning/impact of 'IPC only' for the 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 sentence that is front-loaded with the action. It contains no filler or redundant information, though 'IPC only' is somewhat cryptic, it is brief and does not detract from clarity.

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 single-parameter tool with no output schema, the description and schema together provide sufficient context. It covers what the tool does and how the parameter works. It could benefit from a note on return behavior or preconditions, but these are not essential given the tool's simplicity.

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 already provides a thorough description of the parameter (1-based, negative from end, 'last' for previous tab) with 100% coverage. The tool description adds no additional parameter semantics, so the baseline score of 3 applies.

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 action: 'Switch to a specific tab by index'. It specifies the resource (tab) and the method (by index), distinguishing it from siblings like open_tab, close_tab, and move_tab which perform different operations.

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?

There is no explicit guidance on when to use this tool versus alternatives. The description implies use for changing focus to an existing tab, but does not mention cases where other tools would be preferred or any prerequisites like listing tabs to get an index.

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