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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the mutation/safety profile is covered structurally. The description adds real value beyond that: confirm=false previews the change, and it explains the prior locked-selection behavior being remedied. It does not detail whether switching drops prior-resource state, which keeps it from a 5.

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?

Purpose is front-loaded and the parameter notes are efficient and useful. The historical aside ('until now the first one ever used stayed locked in with no way out') is slightly editorial but does convey the motivating context, so it mostly 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 three-parameter switching tool with an output schema already present, the description covers purpose, plan gating, parameter semantics, and preview behavior adequately. Only the precise after-effects of switching (e.g., what happens to prior selection) are left unstated.

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?

With schema description coverage at 0%, the description carries the full burden and does so: it enumerates the five valid service values, describes resource as the full id from that service's list tool with a Business Profile example format, and explains confirm=false as a preview. All three parameters gain meaning beyond the bare 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 ('Switches WHICH single Google resource this account works on') and enumerates exactly the five resource types affected. An agent can distinguish this selection-changing tool from the many connect_* siblings that establish connections rather than changing the active selection.

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 states applicability explicitly: one resource at a time on Free/Pro plans, and 'Agency plans use several at once and do not need it,' which is a clear when-not condition. It also directs the agent to the appropriate list tool to obtain the resource id, leaving little to inference.

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