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

Annotations only cover safety (readOnly, non-destructive, closed-world); the description goes well beyond them by disclosing the result cap (three cards), the exact fields returned, the meaning of `in_progress: true`, and the `alternatives` fallback when nothing matches. That is exactly the behavioral context annotations cannot supply.

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 usage condition, then the return shape and edge cases. The field enumeration is dense but each item (shape, languages, stops, minutes, who it is for/not for, premium, page_url) earns its place since no output schema exists.

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 and readOnly-only annotations, the description fully carries the return-value burden: card fields, the in_progress marker, and the no-match `alternatives` behavior. Nothing an agent needs to interpret results or call correctly 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%, so query, limit (1-3) and locale enum are already documented in the schema. The description adds no parameter-level detail such as query phrasing or locale behavior, 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?

States a specific verb (searches) and resource (published journeys) with the scope 'guided, step-by-step journey on a topic, a skill or an exam'. It implicitly separates itself from browse_journeys by being a query-driven search rather than a browse, but no sibling is named explicitly.

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?

'Use when the user wants a guided, step-by-step journey on a topic, a skill or an exam' gives a clear triggering condition. There are no explicit when-not conditions or named alternatives (e.g. browse_journeys, list_journey_categories), so an agent must infer the boundary.

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