get_pixels_rect

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

With no annotations provided, the description fully bears the burden of behavioral disclosure. It states the operation is a read ('Read all pixel colors'), which implies non-destructiveness, but does not detail permissions, file existence requirements, or coordinate system origin. The return format is covered, but deeper behavioral traits are missing.

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 uses a clear docstring format with Args and Returns sections, front-loading the main purpose. It is reasonably concise without extraneous content, though the return format repetition could be trimmed slightly. Overall efficient and structured.

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 return format (JSON array of pixel objects) and all parameters, which is good for a read tool. However, it omits context like coordinate origin, error handling, file must exist, and behavior when layer is missing. Given the tool's complexity (7 params, no output schema), additional contextual details would improve completeness.

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 0%, so the description must compensate. It lists all 7 parameters with brief explanations (e.g., 'Top-left x coordinate'), adding some meaning beyond parameter names. However, it lacks constraints like bounds, valid file types, or input validation rules, leaving gaps in full understanding.

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 'Read all pixel colors in a rectangular region,' specifying the verb (read) and resource (pixel colors in a region). It distinguishes from sibling tools like get_pixel_color (single pixel) and get_composite_rect (composite), so purpose is well-defined.

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 implies usage for reading region pixel data via the Args list, but it does not explicitly state when to use this tool versus alternatives (e.g., get_pixel_color for single pixel). No when-not scenarios are mentioned, leaving guidance implicit.

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