create_lifeline

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

With no annotations, the description must carry the full burden of behavioral disclosure. It indicates a mutation ('Create') but provides no details on side effects, error conditions, or whether the interaction must exist. There is no mention of what the tool returns or how it handles invalid inputs, leaving significant behavioral ambiguity.

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 a single, focused sentence that front-loads the action and resource. There is no extraneous text, and it achieves maximum brevity while still conveying the core purpose.

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?

The tool is simple, but the description is too sparse for an agent to call it correctly without additional knowledge. It does not explain the relationship between the lifeline and the interaction, whether the interaction must be provided as an existing element, or what the output (despite an output schema being present) will look like. Key context such as prerequisites and expected parameter values 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 0%, so the description is responsible for explaining the parameters. It does not mention 'name' or 'interaction_id' at all. While the schema titles ('Name' and 'Interaction Id') give basic hints, the tool description adds no semantic meaning, leaving the agent to infer what values are expected and how they relate to the UML model.

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 clear verb ('Create') and a specific resource ('Lifeline inside a UML Interaction'). It distinguishes from other create_* tools by naming the exact element type, though it doesn't explicitly contrast with siblings like create_interaction or create_message. The purpose is unambiguous for users familiar with UML.

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?

No guidance is given on when to use this tool versus alternatives, nor are any prerequisites mentioned (e.g., the interaction must already exist). The description simply states the action without context on how it fits into the modeling workflow or when it should be chosen over similar creation tools.

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