List Browsers

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

No annotations exist, so the description carries the full burden, and it does disclose the return shape: each item carries cdp_url, live_view_url, and connect_url/connect_command for running browsers. It also discloses the filter (only active instances) and the pro tip that connect_command can be executed directly. Missing only minor traits like ordering or whether stopped browsers ever appear.

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 sentences, front-loaded with what it lists, then immediately the payoff (identity with create_browser's connection info) and the actionable conclusion. No sentence is 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 and no annotations, so the description must explain returns — it does, describing the per-item fields and the distinction between running browsers and the rest. A note on what identifies each entry (name/id) or ordering would close the remaining gap, but an agent can call this correctly as written.

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 there is no parameter semantics to explain and the baseline of 4 applies. The description correctly keeps its focus on return values instead of inventing parameter guidance.

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 and resource ("List all active browser instances") with a scoping qualifier ("active"). It also names create_browser as the source of the identical connection fields, which lets an agent relate it to a sibling, though it doesn't explicitly contrast with list_browser_files or the delete tool.

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?

Gives a concrete second use case — as a reconnect path via connect_command — which is real guidance an agent can act on. It stops short of stating when not to call it or naming alternatives to pick instead, so it is clear context without explicit exclusions.

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