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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses the important destructive behavior of replacing all existing steps when steps are provided, but this info is already in the schema. It does not mention authentication, permissions, or whether other fields are partially updated, leaving significant gaps for a mutation tool.

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 two sentences with no fluff. It front-loads the main action and then provides the critical side-effect of steps replacement. Every sentence earns its place.

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 mutation tool with 6 parameters and no output schema, this description is minimal. It tells what the tool does and one behavior, but does not clarify the meaning of 'settings', partial update semantics, or required fields (journeyId is only shown in schema). It is adequate but lacks completeness for an agent to fully understand the tool's scope.

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 the baseline is 3. The description adds no parameter-level detail beyond what the schema already provides; it mentions 'name, settings, or steps' but does not explain specific parameters like isEnabled, description, or timeoutSeconds.

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 tool's function: 'Update a journey's name, settings, or steps.' It uses a specific verb ('update') and resource ('journey'), and distinguishes it from sibling tools like create_journey, delete_journey, and get_journey by indicating that it modifies an existing journey.

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 implies usage for modifying an existing journey but does not explicitly state when to use it versus alternatives or provide exclusions. It only mentions a behavioral nuance ('When steps are provided, all existing steps are replaced'), without guidance on partial updates or prerequisites.

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