system_login

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

The description adds significant context beyond the sparse annotations: it warns about password logging, mentions credential caching, details the return dict structure, and notes reauth behavior. It fully discloses security implications and side effects, with no contradiction to the readOnlyHint=false and destructiveHint=false annotations.

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 well-structured with purpose, security note, args list, and returns, and every sentence adds value. It is slightly longer than necessary but the security warning is important. A minor condensation could improve it, but it remains efficient.

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?

With no output schema and minimal annotations, the description covers all necessary aspects: purpose, security, parameter semantics, return format, and relation to sibling tools. It is complete enough for an agent to select and invoke the tool correctly.

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%, but the description's 'args' section explains every parameter with meaningful context (e.g., reauth forces re-authentication, registry defaults to Docker Hub, dockercfg_path is a custom config). This fully compensates for the schema's lack of descriptions.

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 opens with 'Authenticate with a Docker registry,' a specific verb+resource statement that clearly defines the tool's action. It also distinguishes itself from siblings by explaining how credentials enable image_pull/image_push and are cleared by system_logout.

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?

Explicit guidance is given: prefer running `docker login` on the host instead, avoid calling from an agent loop due to security, and use system_logout to clear credentials. This clearly states when and how to use the tool versus alternatives.

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