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

The readOnlyHint annotation already establishes this is a safe read operation. The description adds meaningful behavioral context beyond the annotation: the result already includes a rendered palette with PNG, PDF, ASE, JSON and CSS downloads, and warns against presenting archive anchors as recommended colours. This goes beyond what structured annotations convey, though it does not detail every output behavior.

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 compact yet information-dense: it opens with the core purpose, immediately distinguishes it from colour_passport, then gives the crucial output-handling and downstream-palette instructions. Every sentence carries operational value without padding.

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?

Given the tool has a single well-documented parameter, an output schema, and readOnlyHint, the description covers the remaining important context: when to call it, what the output contains, how to present it, and what to do if the agent selects its own palette. This is complete enough for correct invocation and follow-through.

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 for the single `hex` parameter is 100%, so the schema already explains the parameter. The description does not add further parameter-level detail, which matches the baseline of 3 for fully documented 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 states a specific function: produce a compact semantic fingerprint for a single hex colour. It also distinguishes itself from colour_passport by emphasizing that this tool returns the fingerprint format alone, so an agent can choose correctly among siblings.

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?

Explicitly says when not to use it: use colour_passport for a general colour profile, and use this only when the user explicitly asks for the fingerprint format alone. It adds a downstream instruction to call palette_finalize when the agent forms its own final palette, giving clear routing and follow-up behavior.

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