browser_tabs

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

Annotations already establish the tool is not read-only and not destructive/open-world; the description adds critical runtime behavior: page-opened tabs appear in observations, target_id is stable via '#handle', and index is unstable across list changes. This explains why an index read earlier may point at a different tab, which annotations alone cannot convey. It does not disclose session persistence or close side effects, but the core risk is covered.

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 compact: a one-line action summary followed by a focused paragraph on handle/index pitfalls. Every sentence contributes either scope or usage nuance, with no 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 multi-action 5-parameter tool, the description covers the most important usage pitfalls and the current-tab default, and the output schema exists to document return shape. The main gap is the absence of explicit parameter-to-action mapping for url and session, though defaults and the opening action list make these mostly inferable.

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?

With 0% schema coverage, the description must compensate, and it does for the two hardest parameters: target_id and index, including their semantics and defaults. It also grounds action='list' by referencing the '#handle' it prints. However, url, session, and the full action value set are not explicitly defined, leaving some inference required.

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 opening line 'List, open, switch to, or close tabs' gives a specific verb set and resource, making the tool's scope immediately clear. It does not explicitly contrast with sibling tools like browser_open or browser_close, but 'tabs' as the resource and the multi-action framing differentiate it well enough.

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?

The second paragraph gives explicit how-to guidance: prefer target_id over index because indexes are positional and renumber, use index only when listing and acting in the same breath, and omit both to target the current tab. This is clear context for when each addressing mode should be used, though it does not name alternatives such as browser_observe or browser_open.

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