tab_list

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

No annotations are provided, so the description carries the full burden. It clearly signals a read-only listing operation and specifies the output fields, which is substantial transparency for a simple zero-parameter tool. It doesn't elaborate on edge cases like empty tab list or ordering, but nothing suggests hidden side effects.

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?

A single, front-loaded sentence with no filler. Every word adds information, and the list of returned fields is presented compactly.

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, no-output-schema tool, the description fully covers what an agent needs: what it does and what information it returns. The tool is trivial to invoke, and the listed fields (index, active, title, URL) are sufficient context for interpreting the result.

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 has zero parameters, and the rubric gives a baseline of 4 for such cases. The description doesn't need to add parameter meaning; it correctly avoids mentioning parameters that don't exist.

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?

States a specific verb ('Lists') and a clear resource ('open tabs') and enumerates the returned fields (index, active, title, URL). This distinguishes it from the modifying sibling tools like tab_open, tab_switch, and tab_close without needing to inspect them.

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 description implies the tool is for inspecting current open tabs, but it provides no explicit when-to-use guidance or alternatives. With siblings like tab_open and tab_switch, the intended usage is inferable, but there is no stated exclusion or comparison.

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