set_opacity

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

Discloses critical behavior beyond annotations: multiplicative blend with fill/stroke alpha, and opacity 0 still renders/exports/hit-tests. Return value is also stated. No contradiction with 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?

Two sentences packed with essential info, front-loaded with purpose, no filler.

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 simple 2-param tool with no output schema, description covers purpose, semantics, alternatives, and return value—fully sufficient.

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 covers both parameters at 100%, but description adds semantic clarity (transparent to opaque, multiplicative effect) that enriches understanding beyond plain schema descriptions.

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 specific verb and resource: 'Set a node's layer opacity' with range. Explicitly distinguishes from siblings by mentioning set_visible and delete_nodes.

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?

Provides clear when-to-use vs alternatives: opacity 0 still renders, so use set_visible to exclude and delete_nodes to remove. Offers explicit alternatives and exclusions.

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