List the connected Google accounts

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

Annotations already mark the operation read-only, idempotent, and non-destructive. The description adds useful behavioral context beyond those: the tool reveals the default account behavior, and it explicitly notes the call incurs no API cost. It doesn't describe output format, but no output schema exists and this is a simple list operation.

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 two compact paragraphs with no wasted words. The main purpose is front-loaded in the first sentence, and the second sentence explains downstream usage and cost without redundancy.

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?

Given no input parameters and ample annotations, the description covers everything an agent needs: what accounts are shown, how the default is represented, and how to use the returned names in other tools. The lack of an output schema is mitigated by the direct description of the listing content.

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 accepts zero parameters, so the schema fully covers parameter semantics (100% coverage). Baseline for zero parameters is 4; the description's mention of the `account` parameter on other tools clarifies how the returned names are consumed, adding slight context but not changing this tool's 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 starts with a specific action and resource: 'Show every Google account this server can act as,' and uniquely distinguishes this tool from siblings by also revealing that it identifies the default account when no account is named. This separates it clearly from auth_status or quota_status.

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 when to use the results by instructing the agent to 'Pass one of these names as `account` on any tool to act as that library instead of the default.' It also adds a cost characteristic ('Costs no API call') that informs decision-making, though it doesn't name alternative tools or exclusion criteria.

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