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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds a sketch of the returned content ('each step, what happened and when'), which is useful given no output schema, but says nothing about missing-run behavior, size limits, or pagination.

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 zero-waste sentence that front-loads the core concept. It is slightly indirect and fragmentary, but nothing is padded or 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?

For a simple one-parameter read tool with full annotation coverage, the definition is minimally adequate. However, with no output schema the description is the only source of return-value information, and 'each step, what happened and when' is too thin to tell an agent what a step record actually contains.

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% and the single runId parameter is fully documented in the schema (including its source: list_journey_runs or get_contact). The description adds no parameter-level meaning, so the 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?

The description conveys the resource well: a journey run is 'one person's path through a journey' with 'each step, what happened and when.' That is a clear depiction of what the tool returns, though the verb is only implied by the name and it never distinguishes itself from siblings like list_journey_runs or list_journey_people.

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, no prerequisites, and no mention of alternatives such as list_journey_runs (which is where the required runId comes from, per the schema). The description alone gives the agent no routing information.

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