system_login

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

Discloses security risk of password logging, caching behavior, and relationship with other tools. No contradiction with annotations (readOnlyHint=false, destructiveHint=false).

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?

Every sentence adds value: main purpose, security warning, usage guidance, parameter list, return info. Well structured and front-loaded.

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?

Completely covers all aspects: why, when, how, parameters, return values, security, prerequisites, and relationship to other tools. No gaps remain.

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 coverage is 0%, but description adds detailed parameter explanations for all 6 parameters, including defaults and purpose. Also explains return dict contents.

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?

Description clearly states 'Authenticate with a Docker registry' with specific verb and resource. It distinguishes from sibling system_logout by mentioning clearing credentials.

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 to use (for private repos via image_pull/image_push) and when not (prefer docker login once, avoid agent loops). Mentions alternative system_logout to clear credentials.

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