set_instanced_mesh

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

With annotations only covering idempotent/readOnly/destructive hints, the description carries the important behavioral context and does so well: changes are LIVE PREVIEW only, NOT saved to source code, lost on reload, recorded in pending_changes (which routes to code edits), and undoable via revert_changes. That persistence and recovery profile is exactly what an agent needs and is nowhere in the annotations or schema.

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 sentences and a bracketed tag, with the highest-stakes fact ([LIVE PREVIEW] — not saved, lost on reload) front-loaded ahead of the mechanical field list. No filler or repetition of schema content.

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?

No output schema exists, and annotations already cover the safety/idempotency profile, so the description does the heavy lifting on preview persistence and undo, which it covers fully. The remaining gap is identification semantics (name vs uuid, both optional) and return behavior on success/failure.

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 60%, so the schema already documents name, uuid, and count. The description restates three of the five fields (count, visibility, frustumCulled) but adds no syntax, units, or constraint detail, and does not clarify the name-vs-uuid identification ambiguity (0 required params). Baseline 3 for adequate-but-not-additive parameter 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 second sentence gives a specific verb (Change) and resource (InstancedMesh) plus the exact mutable fields: count, visibility, frustumCulled. This clearly distinguishes it from sibling setters like set_object_transform and from the read-only instanced_mesh_details. It stops short of explicitly naming a sibling it is not, so 4 rather than 5.

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 establishes the operating context (live/browser-only preview, not persisted) and points to reconcile paths: pending_changes and revert_changes. However, it never says when to prefer this over alternatives such as set_object_transform, nor does it state preconditions (e.g. when a live-preview edit is appropriate vs a source edit). Usage is implied rather than specified.

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