set_blend_mode

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

Discloses that it only affects compositing, not fills, and returns { ok, nodeId }. Annotations state non-destructive mutation, and description aligns, adding useful behavioral context beyond annotations.

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?

Three concise sentences, front-loaded with core action, no redundancy. Every sentence adds essential information.

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?

Given no output schema, the description still mentions the return value structure. It explains the effect and distinguishes from related tools, making it complete for an agent to understand usage.

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 100% with basic descriptions, but the tool description adds significant value by listing example blend modes and explaining PASS_THROUGH semantics. This provides deeper meaning than the schema alone.

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 clearly states it sets the blend mode of a node, lists examples of blend modes, and distinguishes from set_fills and set_opacity. It also clarifies PASS_THROUGH only for groups/frames. Highly specific and distinct from siblings.

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?

Explicitly says when to use (set compositing) and when not (use set_fills or set_opacity for fills/opacity). Provides a specific guideline for PASS_THROUGH only on groups/frames. Excellent differentiation from sibling tools.

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