browser_list_tabs

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

With no annotations provided, the description must carry the transparency burden. It communicates a read-only action ('List all open tabs...') and states what is returned (tab IDs and URLs), plus a prerequisite. However, it does not explicitly rule out side effects or describe error behavior (e.g., missing session), which keeps it at an adequate but not rich level.

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 concise and front-loaded: the first sentence states the purpose, followed by a prerequisite and a brief usage note. The Args section is minimal and necessary given the schema lacks parameter descriptions. Every sentence earns its place.

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 simple one-parameter list tool with an output schema present, the description is nearly complete. It covers the prerequisite, parameter semantics, and how to use the result. It could mention behavior when no session exists, but that is a minor gap given the tool's simplicity.

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 schema's session_name property has only a title and default, with no description (0% schema description coverage). The description compensates with an Args section explaining 'Browser session to query' and noting the default. This fully covers the single optional parameter and adds meaning beyond the schema.

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 opens with a specific verb and resource: 'List all open tabs in a browser session with their tab IDs and URLs.' This clearly distinguishes the tool from siblings like browser_list_sessions (sessions vs. tabs) and browser_open (opening vs. listing).

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 explicitly states a prerequisite: 'browser_open must have been called first.' It also explains how to use the returned tab_id with other browser_* tools, giving clear operational context. It does not explicitly mention when not to use this tool or compare it to browser_list_sessions, so it falls just short of a 5.

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