join_entities

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

The description discloses the source-handle behavior ('first handle = source'), which is useful. However, it omits side effects like whether the original entities are deleted or a new polyline is created, and does not clarify if the source is modified in place. With no annotations, this context is missing.

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, front-loaded sentence with no wasted words. It conveys the operation, input, and result efficiently.

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 simple join operation, the description covers the essential information. It explains what entity types are supported and the source-handle rule. The missing side-effect details lower it slightly, but an output schema exists, reducing the need to describe return values.

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 description adds meaning to the 'handles' parameter by indicating that order matters (first handle = source) and specifying acceptable entity types (lines, arcs, polylines). With 0% schema coverage, this is valuable but not exhaustive.

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 uses a specific verb ('Join') and resource ('touching lines/arcs/polylines'), clearly identifying the operation and result ('into one polyline'). This distinguishes it from sibling tools like trim_entity or break_entity.

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 the use case (joining touching entities) but does not explicitly state when to use this tool versus alternatives. It offers no exclusions or comparisons, so the guidance is only implicit.

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