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

Beyond the readOnlyHint annotation, the description discloses that the image is never stored and is processed in memory only, which is meaningful privacy context. It also reveals extra behavioral traits: the result carries rendered palette downloads, the agent must display them, and archive anchors must not be presented as recommended colours. No contradiction with the read-only annotation.

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 substantial but every sentence earns its place: core function, output details, applicable scenarios, privacy guarantee, and workflow guardrails. It is front-loaded with the main purpose and then logically builds to usage cautions, with no filler or repetition.

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 output schema exists and the annotations cover read-only safety, the description is complete for correct invocation and follow-through. It tells the agent what results arrive, what to show the customer, and precisely when and how to hand off to palette_finalize, covering both the tool's own behavior and the surrounding workflow.

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 100%, so the baseline is 3. The description adds little parameter-specific meaning beyond the schema; it mentions base64 encoding and the up-to-5 colour limit, but those are already present in the input schema. It does not materially clarify archive, n_colours, or media_type beyond their existing descriptions.

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 verb and resource: upload a base64 image and extract its dominant colour palette, matching each colour to a named archive entry with cultural provenance. It also lists concrete outputs (archive name, cultural story, RAL standard, WCAG data) that distinguish it from generic colour-extraction siblings such as extract_image_colours or palette_extract.

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?

The description explicitly names applicable use cases ('product photography, interior photos, artwork, brand assets, and mood boards') and gives clear downstream routing: show the returned downloads to the customer, never present archive anchors as recommendations, and call palette_finalize exactly once if the agent picks its own palette. This is actionable when-versus-alternative guidance.

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