get_pixels

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

Despite no annotations, the description discloses that it reads the composited view, returns hex strings with alpha, and has a 64x64 cap. This is sufficient behavioral context for safe use.

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 sentences, no wasted words. Essential information is front-loaded (verb, resource, output format, constraint).

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 read tool, the description covers the main aspects: what it reads, output format, and size limit. It could mention coordinate system or what happens at canvas edges, but overall it's sufficiently complete.

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?

The description implicitly explains that parameters define a region (x, y, width, height) and filename, but frame is not mentioned and width/height default behavior (null = full?) is ambiguous. With 0% schema coverage, it adds needed context but not fully.

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 the composited pixel colours of a region' with a specific verb and resource. It distinguishes from siblings like draw_pixels (write) and get_palette, making the tool's purpose unambiguous.

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?

It provides clear guidance on the region cap and recommends tiling for larger areas. However, it does not explicitly mention when not to use this tool or suggest alternatives like draw_pixels for writing, though siblings are numerous.

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