login_user

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

No annotations are provided, so the description must disclose side effects and behavior, but it only says 'for write actions.' It does not explain whether login creates a session, returns an auth token, verifies credentials, or persists state, leaving important authentication-flow behavior opaque.

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 one short sentence with no filler. The core purpose is front-loaded, and the credential requirement is included 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?

There is no output schema and no annotation coverage, so the description should explain what happens after login, such as session/token behavior or expected return values. It does neither, which is a material gap for a stateful authentication 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?

Schema description coverage is 100%, and the schema already documents both parameters as 'Twitter password' and 'Twitter username or email.' The description merely restates that credentials are required, adding no new semantic detail, so the baseline score of 3 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 uses a specific verb ('Login') and resource ('Twitter account'), and scopes the operation to 'write actions'. This clearly distinguishes it from all sibling read/search tools and from create_tweet, making its purpose unambiguous.

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 the tool is needed for write actions, giving the agent a clear precondition for using it before mutating operations. It does not explicitly name alternative tools or say when not to use it, but the write-action framing is sufficient context.

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