obs-set-scene-item-blend-mode

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

With no annotations, the description carries the full behavioral burden and mostly fails it: it never states that this is a live mutation affecting on-air output, whether the change is persistent or reversible, what happens with an invalid blend mode, or what error conditions look like. Only the verb 'Sets' hints at 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?

It is a single front-loaded sentence, which is structurally sound, but the parenthetical enumeration of seven blend modes is pure duplication of the schema's blendMode description and earns no place. Removing it would lose nothing.

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?

This is a low-complexity two-required-parameter mutation with full schema coverage and no output schema, so the bar is modest. Still, with zero annotations the description should have flagged the mutating, live-output nature of the call and how to identify the target scene, which it does not.

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 schema already documents all four parameters including the blend mode values. The description merely duplicates the blendMode enum verbatim and adds no meaning about choosing between sceneName and sceneUuid, so the baseline 3 applies.

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+resource: 'Sets the blend mode of a scene item,' which is unambiguous and easily distinguished from the sibling obs-get-scene-item-blend-mode by the set/get contrast. It stops short of explicitly naming the read counterpart or scoping the target item, but the core purpose is clear.

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 when-to-use guidance, no mention of the paired getter for verification, and no prerequisites such as needing the item to exist or the scene to be identified. The only extra content is a parenthetical enum list, which is a value list rather than usage guidance.

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