get_composite_pixel

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

Discloses that it 'flattens a throwaway clone' to composite layers, explaining the internal mechanism. No annotations provided, so description carries full burden and succeeds.

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?

Concise, front-loaded with purpose and differentiation. Uses clear Args list format without redundancy. Every sentence adds value.

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?

Covers purpose, behavior, and parameters well. No output schema, but 'RGBA colour' implies return format. Could be more explicit about return value structure, but adequate.

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 0%, but description documents all 4 parameters: filename, x, y (sprite-global coordinates), and frame_index (starts at 1). Adds meaning beyond schema.

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?

Description clearly states it reads the RGBA colour visible at a pixel by compositing all visible layers. It explicitly distinguishes from sibling 'get_pixel_color' which reads a single cel.

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 explicit usage context: 'what the player actually sees', and contrasts with get_pixel_color for single cel. Suggests use for 'value/CVD QA on grouped/multi-layer scenes'.

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