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

Annotations already declare idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds the meaningful behavioral precondition that the target account must already be authenticated via login, which is not derivable from the annotations or schema.

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 compact sentences with the purpose and example front-loaded and the precondition last. No redundant restatement of the title or annotations, and every clause carries information.

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 two-parameter, annotation-covered tool with no output schema, the description covers what it does, when to use it, and the authentication requirement. It omits whether an in-flight or prepared order is affected by switching accounts, a minor but plausible agent question.

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 both 'label' and 'clientId' are already documented in the schema, including the single-restaurant omission rule. The description adds no format or constraint detail beyond that, so the baseline 3 applies.

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 ('Choose which signed-in account to order with') with a concrete scope ('at a restaurant'). The final sentence explicitly separates it from the login flow, so an agent can distinguish it from siblings like login, logout, and list_accounts without opening a schema.

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 clear use case ('to switch between work and personal') and an explicit precondition ('must already be signed in via login'). It stops short of naming an alternative for the not-signed-in case (i.e., use login first), which leaves a small inference for the agent.

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