system_login

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

Discloses security risk (password logged by clients) and mentions return value, adding context beyond annotations which only indicate non-read-only and non-destructive.

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?

Concise and well-structured: purpose sentence, security warning, parameter list, return type. Front-loaded and no wasted words.

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?

Covers purpose, security, parameters, and return value. Lacks detailed error info but sufficient for a login tool with no output schema.

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?

Describes all 6 parameters with brief but meaningful explanations (e.g., reauth as 'Force re-authentication'), adding value over schema with 0% coverage.

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?

Clearly states 'Authenticate with a Docker registry.' Specific verb and resource, distinct from sibling tools like buildx or compose.

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?

Explicitly advises when not to use (prefer docker login on host, avoid agent loop), providing strong usage guidance.

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