iris_login

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

With no annotations, the description carries the full burden of behavioral disclosure. It does explain the interactive flow (returns URL/code for human entry, requires a follow-up call) and the condition for reuse, which is valuable. However, it does not disclose potential side effects (e.g., invalidating existing tokens), whether the call is blocking, or error behavior if invoked multiple times. A 3 reflects this moderate level of transparency.

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 with no filler. It front-loads the primary action, then immediately gives the return values and next step, and ends with the usage condition. Every sentence earns its place and there is no redundancy with the schema.

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?

Despite having an output schema, the description explains the meaningful output (URL and code) in plain terms, which the schema may not convey. It also covers the workflow (call finish after) and the lifecycle condition. For a login-initiation tool with no parameters, nothing an agent needs to call it correctly is missing.

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 description has no parameter semantics to add. The baseline for 0 parameters is 4; the description appropriately mentions 'the mailbox' but that refers to the overall context, not a specific parameter. There is no gap to compensate for.

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 action ('Start a device-code sign-in'), the resource ('the mailbox'), and the specific protocol (device-code), distinguishing it from siblings like iris_login_finish (which completes the sign-in) and iris_auth_status (which presumably checks status). It also mentions the return values (URL and code), leaving no ambiguity about what the tool does.

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 states when to use the tool: 'Only needed once, or after the refresh token lapses.' It also names the next step, iris_login_finish(), and implies that if you already have a valid token you don't need to call this. This is clear guidance on when to use vs. alternatives.

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