set_supported_blend_mode

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

With no annotations, the description carries the full burden. It usefully discloses that the tool verifies the readback value after setting, which is behavioral context beyond the schema. However, it says nothing about failure modes (e.g. when a blend mode is unsupported), permission needs, or how the readback is surfaced in the response.

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; the long parenthetical example list is slightly padded but still informative and not wasteful.

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 6-parameter mutation tool with no annotations and no output schema, the description covers the core action and the verification step, which is adequate. It stops short of explaining return/readback shape or error behavior, leaving gaps an agent might need when the call fails.

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 high (83%), so the schema already documents the parameters well. The description restates blend-mode examples and mentions the video-clip target, but adds no new syntax or meaning (e.g. how blend_mode interacts with clip_name vs clip_index vs clip_node_id) beyond what the schema provides.

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 (Set) and resource (Blend Mode on a video clip's Opacity component), which is more precise than a generic 'set property' tool. The target component (Opacity) distinguishes it from set_opacity and set_supported_clip_property, though it never names those siblings explicitly.

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?

Usage is implied by the name and description (set a blend mode), but there is no explicit guidance on when to pick this over set_opacity or set_supported_clip_property, nor any prerequisites such as needing a clip selected or located. No exclusions or alternatives are offered.

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