browser_list

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

With no annotations, the description carries the burden and does well: it explicitly states the tool starts nothing and is side-effect free, and clarifies that a non-running browser is "declared and not needed yet" and will be started by the next command aimed at it. It omits any auth or concurrency caveats, but the non-mutating contract is clearly disclosed.

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 answer is front-loaded with what the tool reports, and the sentences are dense with real information. Phrasing like "which one the commands that name none go to" is awkward, and enumerating return fields partly duplicates the output schema, but overall little is wasted.

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, read-only listing tool with an output schema, the description covers purpose, the non-mutating guarantee, and the semantics of "not running" — more than enough to call it correctly. The only gap is the unresolved boundary with the browser_status sibling.

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 baseline is 4. The description adds no parameter meaning because there is none to add, and the empty schema is fully consistent.

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 states a concrete resource (the two browsers, their location/state, and the default focus target) rather than restating the name. An agent can tell it enumerates browsers and reports which one unnamed commands target. It does not, however, differentiate itself from the sibling browser_status, which likely overlaps.

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?

"Starts nothing: it reports what is running, so asking is free" implies this is a safe, cheap read to call when you need to know current browser state. But there is no explicit when-to-use versus browser_status or any of the other read-oriented siblings, leaving the agent to infer the split.

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