Set Active Selection

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the replace-versus-add distinction, the active-object behavior, and the edge case that clear:true ignores other fields. This goes well beyond the schema and gives the agent a realistic model of side effects, though it does not mention return values or error cases.

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 three tightly written sentences with no filler. The core purpose is front-loaded, and each subsequent sentence adds a distinct behavioral rule. Every sentence 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 five-parameter tool with no output schema and no annotations, the description covers the main invocation paths, modes, and the clear edge case. It is slightly implicit about the mutual exclusivity of objects, tag, and material, but overall it gives an agent enough context 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 coverage is 100%, so the baseline is 3, but the description adds meaningful relationships between parameters: the first object becomes the active object, mode only applies to objects, and clear overrides all other fields. This clarifies how the parameters interact beyond their individual schema descriptions.

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 opens with a specific verb and resource: 'Replace or extend the active document's selection.' It clearly distinguishes this from sibling read tools like get_selection by stating its write-like role, and from set_mesh_selection by scoping to the active document selection. The supported selection kinds (objects, tag, material) further clarify what the tool operates on.

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 gives clear operational guidance for modes and the clear flag, but it does not explicitly state when to use this tool versus alternatives such as get_selection or set_mesh_selection. Usage context is implied rather than stated, and there are no exclusions or references to sibling tools.

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