Recolor

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

Annotations already signal readOnly=false and destructiveHint=false; the description adds meaningful behavioral nuance beyond that: it operates on distinct colours in one pass, produces a single undo step, and enforces palette legality by intent. This helps set expectations about scope and side effects.

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 well-structured with a front-loaded summary, a compact bulleted list of operations, and a closing note on the undo-step behavior. Every sentence earns its place, and the format is easy for an agent to scan.

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 12-parameter tool with an output schema and 83% schema coverage, the description covers the behavioral essentials: the five modes, when to use them, palette constraints, region scope, and single-undo-step behavior. The schema handles parameter defaults and valid ranges, so nothing critical is missing.

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 high (83%), but the description adds semantic value beyond the schema by explaining perceptual concepts such as 'shadows cool, highlights warm', 'CIELAB distance', and 'value check'. It also clarifies that amount is a ramp step and how each op relates to the relevant parameters.

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 verb and resource: 'Change colours in a region by intent, staying palette-legal.' It then enumerates five concrete operations (shade, snap, replace, hue_shift, desaturate), which clearly distinguishes this tool from siblings like draw or palette.

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?

Each operation is paired with a use case, e.g., 'shade' is recommended instead of picking a darker hex by hand, and 'desaturate' is useful for a value check. It does not explicitly name sibling tools as alternatives, but the intent-based guidance is strong enough for an agent to decide when to invoke it.

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