gimp_measure

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

With no annotations, the description carries the behavioral disclosure burden. It does this well by defining what each kind returns, noting that color is rgba at image x,y, bbox bounds non-transparent pixels, histogram gives per-channel statistics, and dominant returns top k colors. 'Defaults to the selected layer' also reveals target context, though side-effect safety is only implied by the word 'measure'.

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 carry substantial information with no filler. The primary purpose is front-loaded, followed by a compact enumeration of modes and a useful default-target note. Every word earns its place.

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 the core modes and default layer behavior, and an output schema exists to describe return shapes. But given the complexity of 8 parameters, it leaves threshold undefined, does not clarify which parameters apply to which mode, and omits preconditions such as needing an open image or selected layer.

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 meaningfully explains kind values, maps x,y to color, k to dominant, and implies layer/image targeting via 'defaults to the selected layer'. However, threshold is completely unexplained, channels is only vaguely tied to 'per channel', and per-mode required parameters are not explicitly stated.

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 opens with a specific action, 'Measure pixels instead of guessing from a render', and then enumerates four concrete measurement modes (color, bbox, histogram, dominant) with their exact outputs. This clearly separates the tool from render-related siblings and establishes it as a pixel-level measurement utility.

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?

'Instead of guessing from a render' explicitly tells the agent when this tool is appropriate: whenever exact pixel measurements are needed rather than visual inspection. It does not name a sibling tool explicitly or list exclusions, but the context is clear enough for an agent to choose it over render-oriented tools.

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