pixel_export_gif

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

The description adds behavioral details beyond annotations: 'Transparency is preserved as GIF binary transparency (alpha <= 128 becomes transparent). Source canvases are untouched.' It also describes the return JSON structure and error format, which aligns with idempotentHint=true and destructiveHint=false.

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?

The description is concise and front-loaded: the first sentence states the main purpose, followed by brief clarifications on behavior and return values. No extraneous text.

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?

The description covers key aspects: input constraints, transparency behavior, return format, and error handling. However, it omits details on the scale parameter and out_path validation, which are present in the schema but not reinforced.

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?

Despite 0% schema description coverage in the context signal, the input schema itself contains detailed descriptions for all properties (e.g., scale, duration_ms). The tool description adds clarity by explaining the role of ping_pong and per-frame durations, complementing the 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?

The description clearly states the tool's purpose: 'Combine same-size canvas PNGs into a looping animated GIF.' It specifies the action (combine), input (canvas PNGs), and output (GIF), distinguishing it from sibling tools like pixel_export_png and pixel_export_spritesheet.

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?

The description explains when to use parameters like ping_pong for idle/bounce loops and notes that source canvases are untouched. However, it does not explicitly compare against alternatives like pixel_export_spritesheet or state when not to use this tool, so it lacks explicit exclusions.

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