browser_tabs

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

With no annotations, the description carries the behavioral burden. The word 'List' signals a read-only operation, and the description clarifies what data is returned and that the active tab is the default target for later tools. It could be more explicit about having no side effects, but 'list' sufficiently implies that.

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 short sentences with no filler. The core function is front-loaded, and the second sentence immediately provides actionable usage guidance.

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 zero-parameter list tool with no output schema, this description is complete: it states the return fields and exactly how to apply the result with sibling tools. Nothing needed for correct invocation is missing.

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 takes zero parameters, so the empty input schema fully covers parameter semantics. The description adds useful cross-tool context about tab ids, even though those ids are consumed by sibling tools rather than by this one.

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 uses a specific verb and resource ('List open tabs in the real browser') and names the exact returned fields (id, title, url, active). This clearly separates it from the navigation, observation, and assertion siblings.

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 explains how to use the returned tab ids with other tools and the active-tab fallback, which is the main usage context. It doesn't explicitly say when not to use this tool, but the listing role is obvious and no sibling is an alternative for listing tabs.

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