set_shadow

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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=true) by disclosing that edits are browser-only, never written to source, lost on reload, tracked in pending_changes, and undoable via revert_changes. That non-persistence/undo contract is exactly the context the annotations cannot convey.

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 dense sentences, with the critical '[LIVE PREVIEW]' caveat front-loaded before the capability statement. No filler, though the pending_changes/revert_changes parenthetical makes the first sentence slightly packed.

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 ephemerality, undo path, and which parameter families target objects vs lights for a 15-parameter mutation tool with no output schema. It leaves a gap on target identification (0 required params, name/uuid precedence) but is otherwise complete for correct invocation.

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 73%, and the description adds meaningful grouping the schema lacks: castShadow/receiveShadow apply to 'any object', while bias/mapSize/shadow camera apply to lights. This clarifies several parameters (e.g., cameraNear/cameraFar have no schema descriptions) but omits how name vs uuid selection works.

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: change shadow casting/receiving on objects and bias/mapSize/shadow-camera on lights. An agent can tell it apart from most siblings, though it never explicitly contrasts itself with set_light, which overlaps on light properties.

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?

It gives strong context about the live-preview workflow and names pending_changes and revert_changes, but these are companions rather than alternatives — it never says when to reach for set_shadow versus set_light or set_object_transform. Usage is implied, not prescribed.

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