List browsers

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

Annotations already declare readOnlyHint=true, and the description adds valuable behavior beyond that: 'Reports without starting anything,' the meaning of chrome_running=false, and the relationship with close_browser and implicit browser creation. This fully informs an agent about side-effect-free behavior and state semantics.

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 slightly longer than minimal but every sentence adds meaning: return fields, no side effects, implicit creation, default browser existence, and chrome_running=false semantics. The core purpose is front-loaded in the first sentence.

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?

With no parameters and no output schema, the description carries the full burden and succeeds: it lists the returned fields, explains the default browser, clarifies missing names, and defines the chrome_running flag. An agent has everything needed to invoke and interpret the tool correctly.

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?

There are zero parameters, so the description carries no parameter burden. The baseline of 4 applies, and the description does not waste space inventing unnecessary 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?

The first sentence states a precise verb and resource: 'List every browser this server currently holds' followed by the exact fields returned. It clearly differentiates from sibling list tools like list_pages and list_sessions by focusing on browser-level state.

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 explains when results are meaningful: only browsers already created are shown, a missing name is not an error, and 'default' always exists. It gives strong context for when to trust the output, though it does not explicitly name alternative tools or state when not to use it.

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