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

With no annotations, the description carries the full burden of disclosing side effects. It implies authentication but does not explain session creation, credentials handling, failure behavior, or the purpose of the x-hapi-auth-state parameter.

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 short but redundant ('Logs user into the system. - Log into the system.'), with the second sentence adding nothing. This is padded, not concise.

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?

The tool has 3 undocumented parameters, no output schema, and no annotations. The description only covers the literal action, leaving the agent completely uninformed about inputs, outputs, or operational context, making it inadequate.

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 0%, and the description does not mention any parameter. It fails to clarify what username, password, or x-hapi-auth-state mean, how they interrelate, or expected formats.

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 ('Logs user into the system') with a specific verb and resource, and it is distinct from sibling tools like logoutUser or createUser. However, the redundant second sentence adds no new information and prevents a perfect score.

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?

There is no guidance on when to use this tool versus alternatives, no mention of preconditions (e.g., user already created), nor any exclusions. The description simply states what it does, leaving the agent to infer usage.

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