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

The description adds behavior beyond the readOnlyHint annotation by explaining versioning semantics: defaults to published, supports draft and historical versions. It makes the read behavior concrete and gives the agent an expectation about what will happen when no version is supplied.

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?

Two sentences carry the core operation and versioning behavior with no wasted words. The primary purpose appears first and the default behavior is stated clearly at the end.

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?

This is a simple two-parameter read operation, with readOnlyHint set and full schema coverage. The description gives the launching semantics and required parameters; while it doesn't describe the returned object shape, no output schema exists and the normal expectations for a fetch-by-ID tool are met.

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 schema already documents both parameters fully with 100% description coverage. The description rephrases the version parameter as 'working draft' versus 'historical version', which adds minor color but no new semantic information beyond 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?

The description states a specific verb and resource: 'Get a journey by ID' and explains the version variants (draft, vN, published). This clearly separates it from siblings like get_journey_template and list_journeys, which enumerate or access templates, not a single journey by ID.

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 clear invocation guidance for the version parameter: pass draft, pass vN, or rely on the published default. However, it does not explicitly compare get_journey to alternative retrieval tools or state when it should be used versus those alternatives, so guidance is implied rather than explicit.

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