auth_login

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

Description adds context beyond annotations: explains the flow, that credentials are received automatically, and consequences for API calls. Annotations already indicate safe operation (destructiveHint=false), but description gives useful behavioral details.

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?

Three sentences, well-structured with action front-loaded. No unnecessary words. Each sentence adds value: action, return, when needed.

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?

Fully describes the tool's purpose, flow, prerequisites, and outcome for a 0-param tool with no output schema. Complete for an authentication flow 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?

Input schema has 0 parameters, so schema coverage is 100%. Description does not need to explain parameters; the baseline for 0 params is 4. No further parameter info required.

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 it starts the device authorization flow, returns a verification URL and code, and links API calls to user account. It distinguishes from siblings like auth_logout and auth_status by focusing on initial connection.

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 states when to use: 'Only needed if no OPENEPHEMERIS_API_KEY env var is set and no cached credentials exist.' This provides clear usage conditions and implies alternatives (setting env var).

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