Lock or unlock a scene item in OBS Studio by specifying its scene item ID and desired lock state.
Sets the lock state of a scene item
| Name | Required | Description | Default |
|---|---|---|---|
| locked | Yes | New lock state of the scene item (true to lock, false to unlock) | |
| sceneName | No | Name of the scene the item is in | |
| sceneUuid | No | UUID of the scene the item is in | |
| sceneItemId | Yes | Numeric ID of the scene item |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure, and it says nothing beyond the bare operation. It does not explain that locking prevents the item from being moved or selected in OBS, whether the change is persisted or broadcast to clients, what happens with an invalid sceneItemId, or what the response contains for this mutation.
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?
A single front-loaded sentence with no filler, but its brevity reflects under-specification rather than efficiency for a mutation tool with four parameters. There is no wasted wording, yet the one sentence does very little work.
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?
The tool is simple and per-parameter documentation is complete, which keeps it minimally viable. However, for a state-changing operation with no annotations and no output schema, the definition should at least describe the consequence of locking and the mutation's success/failure behavior.
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%, with each of the four parameters documented inline including the boolean semantics of 'locked'. The description adds no meaning beyond the schema, so the baseline of 3 applies, though it also does not clarify how sceneName/sceneUuid interact with sceneItemId as alternative scene selectors.
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 states a specific verb and resource ('Sets the lock state of a scene item') that unambiguously identifies the operation and pairs naturally with the sibling obs-get-scene-item-locked. It does not explicitly name that sibling or any alternative, but the get/set naming pattern makes the distinction obvious.
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?
There is no guidance on when to use this tool versus alternatives such as obs-set-scene-item-enabled or obs-set-scene-item-index, and no mention of the practical effect of locking an item. The agent is left to infer usage entirely from the name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.