user_login

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

No annotations are provided, so the description carries the full disclosure burden. It fails to mention what the tool returns (likely auth tokens or session identifiers), failure modes for invalid credentials, rate limiting, or whether this establishes state for subsequent calls. For an authentication-critical tool, this is a significant gap.

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 single sentence is front-loaded with the action verb and contains no redundant or wasteful language. However, given the tool's importance and lack of supporting annotations, the description could be appropriately longer without losing conciseness.

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?

Without an output schema or annotations for an authentication tool, the description should explain the return values (tokens, expiration) and side effects (session establishment). It omits these critical details, leaving agents uncertain about how to handle the output or subsequent authentication state.

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?

With zero parameters in the input schema (schema coverage 100%), the baseline score applies. The description does not need to parameter details, and the schema is trivially complete.

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 provides a clear verb ('Verify') and resource ('RecurPost API credentials'), and combined with the tool name 'user_login', distinguishes this authentication tool from content management siblings like 'add_content_in_library' or 'social_account_list'. However, it lacks specificity about what verification entails (e.g., establishing a session vs. just checking validity).

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?

There is no guidance on when to use this tool versus sibling authentication tools like 'connect_social_account_urls', nor does it state that this should be called first before other operations or what prerequisites are needed. The description implies functionality but not usage context.

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