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

Beyond the readOnlyHint annotation, the description discloses key behavioral traits: empty slots are filled by CIEDE2000 matching, interpolation is anchored by locked colours, the optional archive filter scopes the fill pool, and every filled slot returns full citation data. It also states the generated result already includes PNG, PDF, ASE, JSON, and CSS downloads.Set a guardrail about not presenting archive anchors as recommendations. There is no contradiction with annotations.

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 dense but front-loaded: core behavior first, then optional filtering, then return value, then a concrete example, then usage guardrails. Every sentence adds decision-relevant value; nothing is filler or restatement of the tool name.

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 annotations, full schema coverage, and presence of an output schema, the description is complete enough for correct selection and invocation. An agent knows what inputs mean, what filtering is available, what results to expect, and how to behave with downstream tools like palette_finalize.

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 100%, so the baseline is 3. The description adds useful semantic context beyond the schema: the lock-and-fill model, the 12-slot ceiling, the Oxfordshire example, and the meaning of the archive filter. It does not deeply elaborate the size parameter, but the schema already handles that clearly.

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 names a precise operation: lock some palette slots with hex values, fill empty slots with nearest CIEDE2000 archive matches interpolated from locked anchors. It also names the output (citted palette plus render/download artifacts), clearly distinguishing this from siblings like palette_finalize, palette_extract, and archive_search.

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 explicitly tells the agent when to use archive_search instead (large colour collection) and when to call palette_finalize (if choosing a final palette of its own). It also gives a strong when-not-to-do rule: never present derived archive anchors as recommended colours. This is explicit routing and exclusion, not just implied context.

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