horizon_login

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

The annotations only give a bare safety profile (not read-only, not idempotent, closed-world), while the description adds genuinely useful behavior: tokens are held server-side, the session persists across subsequent calls, the server auto-renews with the refresh token after ~8 hours, and only short token hints come back. That is exactly the context an agent cannot derive from the structured fields.

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 tight sentences, front-loaded with the action and scoped by 'for this server'. The closing note about short token hints is slightly redundant given the output schema exists, but nothing is padded.

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 an output schema present, return values need no explanation, and the session/refresh behavior is well covered for an auth tool. The remaining gap is the absence of any guidance on what to do on credential failure or how this interacts with horizon_refresh_token and horizon_logout, plus the fact that four params are accepted while only three are required is never discussed.

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 100%, including defaults, format, and writeOnly masking for the password, so the schema already carries the parameter semantics. The description adds no parameter-level detail such as domain format or base_url fallback, which is the expected baseline 3 when the schema does the heavy lifting.

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 gives a specific verb (Authenticate) and resource (Horizon) plus the side effect of activating a server-side session, which cleanly separates it from the read-oriented siblings like list_connection_servers. It does not explicitly name horizon_refresh_token or horizon_logout, so sibling differentiation is left implicit.

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 token-lifecycle sentence ('subsequent tool calls work immediately', auto-renewal at ~8 hours) implies this is a one-time entry point rather than something to call repeatedly, but there is no explicit when-to-use statement, no precondition checklist, and no pointer to horizon_refresh_token as the alternative once a session exists.

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