ym_check_auth

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

Annotations already declare readOnlyHint=true, so the description doesn't need to restate safety. The description adds valuable behavioral context: it does NOT reveal secret values, and it returns a specific JSON structure with ready/missing/required fields. This goes beyond the schema and 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?

Three sentences, each earning its place: what it does, what it doesn't do, and the exact return shape. Front-loaded with the core purpose, then the critical caveat, then the JSON contract. No waste.

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?

For a zero-parameter, read-only check tool, the description is complete. It states the purpose, the safety boundary (no secret revelation), and the exact return format. An agent has everything needed to call it correctly and interpret the result.

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?

The tool has 0 parameters, so the schema is trivially complete. The description adds no parameter info because none is needed. Baseline 4 for 0 params is appropriate.

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 tool checks whether required credentials are present in the environment, with a specific verb and resource. It also explicitly distinguishes itself from sibling auth-check tools by noting it does NOT reveal secret values, which is a key differentiator.

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?

The description implies when to use this tool: before operations requiring credentials, to verify readiness. It doesn't explicitly name alternatives or exclusions, but the context of sibling tools (e.g., ym_set_price, ym_get_campaigns) makes the use case clear. A clear 'use this when you need to verify auth before calling other YM tools' would push it to 5.

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