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

Annotations already declare destructiveHint=true and idempotentHint=false, so the safety profile is covered. The description adds real value beyond that by disclosing the side effect on queued-but-unsent email, telling the agent exactly what is cancelled when the run is stopped.

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 with no filler; the immediate effect ("takes one person out of a journey now") leads and the email side effect follows. Slightly awkward phrasing in the trailing clause, but no wasted content.

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 one-parameter destructive mutation with no output schema, the description covers the immediate action and the concrete consequence (cancelled queued email), and annotations cover reversibility and destructiveness. Minor gaps remain around reversibility wording, but nothing critical to correct invocation 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 description coverage is 100% with a single runId parameter whose schema text already tells the agent where to source the id (list_journey_runs or get_contact). The description adds no further parameter meaning, so the baseline 3 is appropriate.

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 ("takes one person out of a journey") with the scope qualifier "one person" and "now," which separates it from whole-journey operations like pause_journey or delete_journey. It never names a sibling explicitly, so the differentiation is inferable 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?

The description implies the scenario (removing a single contact from a journey mid-run) but gives no explicit when-to-use guidance or conditions, and never points to an alternative such as pause_journey or resume_journey. Usage is left to inference from the verb and scope.

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