loginUser

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

With no annotations provided, the description carries the burden of behavioral disclosure. It reveals the expected output (API key + session) and that this is a login action, but it does not mention behavior on invalid credentials, session expiration, or any side effects beyond creating a session. Adequate but not deeply transparent.

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 sentences with no redundancy. The primary function and return values are stated first, and the sibling pointer to logoutUser is added efficiently at the end.

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 simple two-parameter login tool with no output schema, the description is largely complete: it states inputs, result, and logout counterpart. It could mention account prerequisites or error cases, but the core calling context is sufficiently covered.

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 input schema already covers both parameters with simple descriptions ('Account email', 'Account password'), so schema coverage is 100%. The tool description does not add further semantic detail beyond the fact that these are used for sign-in, which matches the baseline.

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 names the action ('Sign in'), the credentials used ('email + password'), and the result ('get the app API key + session'). It also explicitly differentiates itself from logoutUser, so an agent can tell this is the authentication entry point.

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 clearly states the tool's role for authentication and points to logoutUser as the counterpart for signing out. It does not mention when to use related auth tools like createNewUser or requestOtp, but the primary usage context is clear.

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