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

Adds substantial context beyond annotations: enabling sends nothing immediately but will email the site's real contacts on every trigger fire, disabled/errored journeys are refused with a `problems` payload, and disabling only blocks new entrants (existing entrants unaffected). These are exactly the side-effect semantics an agent needs before a consequential, outward-facing mutation, and nothing contradicts the readOnlyHint=false / destructiveHint=false / idempotentHint=true 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?

Front-loaded with the operation, then the consequence, then the consent rule, then the failure mode — a sensible order where each clause carries information. The middle sentence is a long em-dash run-on that could be split, but no sentence is filler.

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 no output schema, the description supplies the one return detail that matters (a refused enable returns `problems`), plus the consent requirement and the asymmetry between on and off. It stops short of stating permission/auth requirements or how to inspect the resulting journey state (get_journey is available but not referenced).

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%, so site_id, journey_id and enabled are already documented in the schema and the description only restates the enable/disable meaning. Nothing clarifies user_goal, the least self-explanatory parameter, so the description adds no meaning beyond the schema. 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 and resource plus both directions (on/off), and immediately differentiates itself from state-changing siblings like draft_journey or set_automation_enabled by naming the exact effect: enabling starts emailing real contacts. An agent knows precisely what this tool changes.

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?

Gives an explicit gating condition — only when the user asks, and it must be stated plainly before asking for approval — which is real when-to-use guidance. It does not name sibling alternatives (draft_journey, set_automation_enabled) for the case where the agent instead wants to create or configure a journey, so routing is only partially covered.

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