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

Annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description doesn't need to repeat those. The description adds useful context by stating it confirms which login is active, which is a behavioral trait not fully covered by annotations. No contradictions exist.

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 a single, compact sentence (three short segments) that conveys the essence and usage guidance. Every word adds value; there's no fluff. It is well-structured and front-loaded.

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 that the tool has no parameters and no output schema, the description provides enough context: it names the tool's output (e-mail of the broker) and its usage timing (before other operations). It could be slightly more complete by mentioning the format or that it returns no other data, but it is sufficient for a simple validation tool.

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 has zero parameters, so the schema provides no parameter details. The description correctly does not invent parameters; it focuses on what the tool does. Since there are no parameters to explain, and the description clearly indicates the output (the e-mail of the connected account), a baseline of 4 is appropriate.

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 clearly states the tool's purpose: it shows the connected Agger account (broker's e-mail) and confirms which login is active. Although the name 'agger_list_accounts' is generic, the description adds specificity about what is listed (the connected account) and distinguishes it from other tools like 'authenticate' and 'connect' by focusing on validation of the active login.

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 explicitly says to use this tool to validate the connection before other operations, providing clear context for when to use it. It doesn't explicitly mention when not to use it or name alternative tools, but the context is reasonably clear given the sibling tools like 'authenticate' and 'connect' which likely handle initial setup.

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