Add Features

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

The destructiveHint annotation already indicates a write operation; the description adds the return value and feature format. However, it does not disclose potential error conditions, whether features are appended or replaced, or editing requirements.

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 with no extraneous information. The first sentence states the core purpose, the second adds crucial details. Optimal length for this tool's complexity.

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?

Covers the main purpose, feature format, and return value. Does not mention optional behavior or edge cases, but for a simple tool with few parameters this is sufficient.

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?

Despite 0% schema description coverage, the description provides an explicit example of the feature structure with attributes and geometry_wkt fields, compensating fully for the schema's lack of documentation.

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 ('Add features to a vector layer') and provides the return value and feature format. It does not explicitly distinguish from sibling tools like update_features, but the purpose is unambiguous.

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 on when to use this tool versus alternatives (e.g., update_features, delete_features). Does not mention prerequisites like layer editability or when not to use.

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