set_project_area

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

With no annotations, the description carries the full burden and does disclose visible side effects: the layer is added on top as a red outline and the canvas zooms to it. It does not say whether an existing project area is replaced/destroyed or what permissions are required, leaving a real gap 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?

Two front-loaded sentences capture purpose plus visual behavior, followed by a tight Args block with no filler. Every line 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 four-parameter, no-annotation, no-output-schema tool, the description covers parameters and UI side effects well. It stops short of describing replace/overwrite semantics on repeat calls, which is the one behavior an agent might need to reason about.

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 coverage is 0%, so the description must compensate and does: it documents all four parameters with concrete formats and defaults — file extensions for path, default-to-filename for name, an EPSG example for crs, and a literal filter expression for subset.

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?

States a specific verb and resource ('Set the project shape (polygon layer)') and clarifies scope: this is the base geometry 'every map is built on', which separates it from a generic add_layer sibling. An agent can tell what this does without opening the schema.

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?

Usage context is implied rather than stated — the description makes clear this defines the base area of the project, but it never says when to call it versus add_layer, nor whether it should be set before generate_map. No alternatives or exclusions are named.

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