Creates multiple browser instances for the specified profiles.

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, so the safety profile is covered. The description adds no behavioral detail beyond the action itself—nothing about what happens to existing instances, partial failures, or the effect of keepAlive—so it does little beyond the annotations.

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 concise sentences with the primary action front-loaded and no wasted words. It could be slightly better structured by separating purpose from validation, but it is efficient.

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 bulk mutation tool with 7 parameters and 100% schema coverage, the description covers the primary action and a key prerequisite. However, it omits bulk-operation failure semantics (e.g., what happens if some profile IDs are invalid) and does not address the keepAlive or feature-override behaviors, leaving notable gaps.

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?

Schema description coverage is 100%, so the input schema already documents every parameter in detail. The description mentions profile IDs and workspace ID but adds no syntax, format, or meaning beyond what the schema provides, making 3 the appropriate baseline.

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 specific verb+resource: 'create browser instances in bulk for the specified profiles.' The word 'bulk' distinguishes it from the single-instance sibling start_browser_instance, but the alternative is not named explicitly, so it falls short of a 5.

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?

It offers prerequisite guidance ('Ensure that the provided profile IDs are valid and that the specified workspace ID exists') but does not say when to use this tool versus start_browser_instance or bulk_stop_browser_instance. Usage is implied by 'in bulk' but not made explicit.

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