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

Adds useful behavioral context beyond the readOnlyHint annotation: results are ordered newest first, filters can be combined to find stalled/errored runs, and step-level detail lives in a sibling tool. It does not describe pagination or result shape, but the schema covers cursor and limit mechanics.

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, well-structured sentence that front-loads the core listing behavior, then mentions filters and the intended workflow. No filler words or redundant restatements of the tool name.

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 read-only list tool with six optional, fully documented parameters and no output schema, the description is nearly complete: it gives the ordering, filter options, and a chained next action. The main missing piece is a note about pagination/return envelope, though cursor and limit semantics are present in the schema.

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?

The input schema already documents all six parameters with full descriptions, so the baseline is 3. The description usefully groups start_date/end_date as a 'created_at window' and maps 'journey' to template_id, but adds little detail that is not already present in the schema.

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?

Description uses a specific verb-resource pair ('List journey runs'), states the sort order ('newest first'), and describes the available filters. It also names the closely related sibling list_journey_run_steps, making it easy for an agent to distinguish this listing tool from other journey-related tools.

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 gives a clear context for use—find a run that stalled or errored—and explicitly points to list_journey_run_steps as the follow-up. It does not explicitly state when not to use this tool versus list_journeys or get_journey_run, so it falls short of a full when/when-not set of alternatives.

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