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

With only readOnlyHint=true in annotations, the description carries the disclosure burden and does so richly: the result embeds a full rendered palette with PNG/PDF/ASE/JSON/CSS downloads to surface, derivation anchors must never be presented as recommendations, and self-chosen final palettes must go through palette_finalize. These are substantive behavioural traits no structured field conveys.

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?

Core purpose is front-loaded in the first sentence; the remaining sentences each carry a distinct directive (surface downloads, avoid presenting anchors, call palette_finalize). Dense but not bloated given the behavioural load it must carry.

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 single-parameter, read-only tool with an output schema present, the description covers purpose, the embedded payload and downloads, a safety caution, and the linked follow-up tool. Nothing an agent needs to call it correctly 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?

The input schema already documents name fully (100% coverage, including the 'Bourton Honey' example), so the description's 'any named archive colour' adds no new parameter-level semantics. Baseline 3 applies since the schema does the heavy lifting.

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?

States a specific verb and resource: 'For any named archive colour, return historical variants, lighter and darker versions with archive matches, and cultural siblings.' The concrete output list distinguishes it from siblings like colour_combination or colour_harmonies without needing to open their schemas.

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?

Gives a clear when-to-use signal ('Essential for designers exploring around a colour') and explicitly routes the follow-up action to sibling palette_finalize when the agent chooses its own final palette. Lacks an explicit when-not-to-use statement against other colour-exploration siblings, so it stops short of a 5.

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