Tabs

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

The annotation readOnlyHint=false already signals that this tool is not purely a read operation, so the description's main contribution is the note that switching preserves page state and JS globals — genuine behavioral context not in the schema. It does not disclose what 'close' destroys, whether indices shift after closing, or any permission/state-loss caveats for a mixed read/write tool.

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?

Two tight sentences with the action set front-loaded and the state-preservation caveat second; no filler. It is arguably over-compressed for a four-action tool, but nothing is wasted.

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 multiplexing four distinct operations with no output schema, the description never says what 'list' returns (titles, URLs, indices?) or what a successful create/switch/close yields — information an agent needs to chain calls. The behavioral asymmetry between the mutating actions is also unaddressed.

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 coverage is 67%, with url and index already documented inline and the action enum self-explanatory. The description adds nothing about how index relates to the list output or whether url is required for 'new', so it does not fully compensate for the remaining coverage gap; baseline 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 names a specific resource (tabs) and enumerates the four supported verbs (list, create, switch, close), which map directly to the action enum. It does not distinguish itself from siblings such as 'open', 'close', or 'navigate', so an agent cannot tell from the text alone when this tool supersedes 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?

There is no when-to-use/when-not-to-use guidance and no mention of alternatives, despite obvious overlap with 'open', 'close', and 'navigate'. The only implicit hint is that switching preserves state, which suggests preferring switch over reopen, but the agent must infer this.

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