Add Field

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

With no annotations, the description must carry full weight. It only states the action and the allowed types, but does not disclose side effects (e.g., permanent modification), required permissions, or error conditions (e.g., duplicate field name, incompatible layer type). The behavioral traits are minimally addressed.

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 consists of two short sentences with no redundancy. The first sentence conveys the core purpose, and the second provides a list of valid field_type values. Every word 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 five parameters and no annotations, the description is too sparse. It fails to mention return values, error conditions, or constraints (e.g., layer must be a vector layer in edit mode). The agent lacks enough context to invoke this tool confidently.

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%, yet the description only adds value for field_type by listing the allowed values. Other parameters like layer_id, field_name, length, and precision are not explained at all. This partial compensation is insufficient for the low 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 explicitly states the action ('Add a new field') and the target resource ('vector layer'). It also lists the valid field_type values, which distinguishes it from siblings like delete_field and rename_field. The verb+resource combination is specific and 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 is provided on when to use this tool versus alternatives (e.g., add_vector_layer, delete_field). There is no mention of prerequisites, such as whether the layer must be in editing mode or whether field names must be unique. The description does not help the agent decide when to use this tool.

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