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

Annotations indicate readOnlyHint=false and idempotentHint=false, implying a state-changing operation that may have side effects. The description does not disclose these behavioral traits at all—it only says 'invoke a journey run' without explaining what happens (e.g., sends messages, triggers automations) or whether it is asynchronous. With no further context, the agent is left guessing about side effects and reliability.

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?

The description is extremely concise: one sentence plus an example. The core purpose is front-loaded, and the example is directly relevant to parameter usage. There is no extraneous information, making it easy for an agent to parse quickly.

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?

Given that this is a mutation tool with no output schema, the description should explain what happens after invocation (return value, async behavior, possible errors). It only gives an example, leaving out crucial execution details. The presence of nested objects (data and profile) and the ambiguity of user_id resolution suggest the description is incomplete for an agent to invoke this correctly in all cases.

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%, as all four parameters (data, profile, user_id, template_id) have descriptions. The description adds a clarifying example and notes that template_id refers to an existing template, which is a small enhancement. However, it does not explain how user_id relates to profile or data beyond what the schema already says, so it meets but does not exceed the baseline for full coverage.

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 clearly states the action ('Invoke a journey run from a journey template') with a specific verb and resource. It also immediately clarifies that template_id refers to an existing template in the workspace, and provides a concrete example. This distinguishes it from siblings like invoke_automation_template by explicitly mentioning 'journey run' and 'journey template'.

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 does not provide any guidance on when to use this tool versus alternatives. It does not mention prerequisites, like whether the template must be published, nor does it contrast with invoke_automation_template or invoke_ad_hoc_automation. An agent would have to infer usage from the example, which is insufficient for routing.

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