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

Annotations already declare destructiveHint=true and idempotentHint=false. The description adds genuinely useful context that annotations cannot: people already in the journey are held in place rather than removed or advanced. It stops short of stating reversibility or what happens to contacts mid-step.

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?

A single front-loaded sentence describing the operational effect with zero filler. Nothing is repeated from the title and 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?

For a state-mutating journey tool with annotations covering the safety profile and a fully documented single parameter, the core effect is covered. Missing is the reversibility signal (pause vs. permanent stop) and any note on in-flight contacts, which an agent managing journey lifecycle would want.

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?

One parameter with 100% schema description coverage, and the schema already tells the agent to get journeyId from list_journeys. The description adds nothing about the parameter, which is acceptable given the schema does the work.

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 states a specific effect: it stops new entrants and freezes current participants in place. That distinguishes it well from delete_journey and stop_journey_run in spirit, but it never names the sibling that resumes the journey, so the differentiation is inferred rather than stated.

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 when-to-use guidance and no mention of alternatives. An agent must infer on its own that resume_journey reverses this, that delete_journey is the permanent counterpart, and that stop_journey_run affects a single run rather than the whole journey.

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