Identity

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

With no annotations provided, the description carries the full burden of disclosure. It reveals the asynchronous nature of sign-in, the need to poll for results, and the external user interaction required. This goes well beyond the schema by explaining the 'how' and 'why' of the behavior.

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 sentences: the first states the core purpose, the second explains the most complex usage flow. No filler or redundancy, and it front-loads the key 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?

Given the output schema is present, return values need not be explained. The description covers the tool's actions, the sign-in flow, and the constraint, making it fully sufficient for an agent to invoke the tool correctly.

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 coverage is 50% (provider is described, action is not). The description clarifies the action parameter by showing how 'signin' and 'show' are used in the flow, though it doesn't explicitly explain the 'signout' action or the provider parameter. This partial compensation is strong but not complete.

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 explicitly states 'Show, start or clear the service identity,' giving a specific verb+resource and distinguishing this tool from sibling tools focused on connections, inputs, or geometry. The reference to the device-code flow further clarifies the tool's unique purpose.

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 provides an explicit step-by-step usage for the sign-in flow: start with action=signin, poll action=show, and relay pendingSignIn. It also explains the rationale ('The service has no browser, so relaying that prompt is the only way in'). It doesn't name an alternative tool, but the context makes it clear when to use this identity tool.

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