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

Annotations cover the safety profile (readOnly=false, destructive=false, non-idempotent), and the description adds what annotations cannot: the return is a secure expiring setup URL, the operation is incomplete until the user authorizes, and the correct verification tool. This is behaviorally rich beyond 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?

Four short sentences, front-loaded with the action and return value, followed by the critical constraint and the follow-up step. No sentence is redundant.

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?

An output schema exists, yet the description still conveys the one thing an agent must act on (surfacing the URL and not treating it as success). For a single-parameter connection tool, nothing needed to call it correctly is missing.

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 100%, and the schema already documents siteId as the 'Owned Nimo site ID from list_sites'. The description reinforces the 'owned Nimo site' framing but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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?

States a specific verb (Connect), resource (PostHog), and scope (an owned Nimo site). It clearly distinguishes itself from the read-side sibling by naming get_posthog_connection_status as the verification step.

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 prescribes the workflow: show the exact URL, never ask for API keys in chat, and recognize that a link is NOT a completed connection — then check status after authorization. Both when-to-use and what-not-to-do are stated.

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