List, open, switch or close tabs

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

Annotations are empty, so the description carries the full burden. It does disclose two valuable side effects not present in the schema: "open" makes the new tab active and "select" changes the default target for other tools. However, it says nothing about error behavior, whether tab state survives a close, or what a "list" returns, leaving meaningful gaps for a mutation-capable 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?

One framing sentence followed by four compact clauses, each mapping a mode to its effect. Front-loaded with the resource and zero 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?

There is no output schema or annotation set, and for an action-dispatch tool the description covers the four modes and the active-tab contract adequately. Only the shape of the "list" result and failure modes are unaddressed, which are minor for this tool's complexity.

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% and the schema already maps url to "open" and tabId to "select"/"close". The description reinforces the action-to-parameter pairing but adds no format detail (e.g. what a tabId looks like, whether url accepts relative paths), so it does not compensate much for the uncovered portion.

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 the resource (browser tabs) and enumerates each of the four action modes the tool supports, tying each to a concrete effect. An agent can tell immediately what this tool does versus the many single-purpose browser_* siblings such as browser_navigate or browser_click.

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 gives real operating context: "select" makes a tab active and "other tools act on the active tab by default," which is exactly the routing information an agent needs. It implies but never explicitly states the boundary against browser_navigate (which presumably acts on the current tab), so the when-not guidance is only partial.

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