add_landscape_spline_control_point

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

Annotations declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is already covered. The description adds important behavioral context beyond those hints: coordinates are landscape-local rather than world, the width value is a half-width, and the response's control_point_index is what downstream edit tools use. It stops short of describing prerequisites such as whether a spline component must already exist, but it clearly flags the coordinate-space pitfall.

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?

Front-loaded with the core action, then quickly covers sequencing, coordinate-space warning, width semantics, and return usage. Every sentence earns its place, and the explicit returns block is useful because no output schema is provided. It could be slightly tighter, but the information density is high and well organized.

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 3-parameter mutation tool with a fully covered input schema and no output schema, the description is largely complete: it explains placement semantics, the half-width meaning, and the index needed by later segment/edit tools. It omits prerequisites like whether a spline component must already exist, but otherwise gives an agent enough to call the tool correctly.

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 100%, so the baseline is 3. The description adds meaningful operational semantics for location: it stresses landscape-local coordinates and tells the agent to subtract the landscape's location, preventing a common failure. It also clarifies that width is a half-width, though the schema already states this, so the value over baseline comes mainly from the coordinate guidance.

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: 'Add a control point to a landscape's spline component'. It distinguishes the tool from siblings by framing it as the first half of laying a road/river/path and naming the follow-up tool, add_landscape_spline_segment. An agent can tell what this does without opening any 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?

Explains when and how to use it: to start a road/river/path across terrain, with consecutive points connected by add_landscape_spline_segment. It also warns about a critical prerequisite – subtract the landscape's location using get_landscape_info before passing coordinates – which is exactly the kind of guidance that prevents silent placement errors.

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