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

Annotations only declare readOnlyHint=true; the description goes well beyond that by disclosing that the result carries rendered palette downloads (PNG, PDF, ASE, JSON, CSS), instructing the agent to show them to the customer, warning never to present archive anchors as recommended colours, and specifying the palette_finalize follow-up. This is rich behavioral context that shapes how the agent presents results.

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?

Though dense, every sentence earns its place: purpose summary, alternative-tool guidance, style_context guidance, what to display, a consumer-safety warning, and a follow-up action. The most important scoping information is front-loaded, and there is 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?

With an output schema present, the description needn't spell out return values, yet it still mentions the delivered palette downloads and the 'never present anchors' caveat — critical agent behavior for this compound pipeline. All 8 parameters are already documented in the schema, required count is 0, and the description covers usage, exclusions, and follow-up steps. Nothing an agent needs to invoke 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?

Schema coverage is 100%, so the baseline is 3. The description adds a small amount of parameter context — style_context examples and the rationale for coherent archive matching — but it largely repeats what the schema already documents for each of the 8 parameters. No additional semantics for k, model, image_url, or grey_card_hex are provided beyond their schema 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?

Description opens with a specific compound-endpoint summary — one image in, full creative brief out — and enumerates the concrete outputs: dominant colours, archive matching, scene understanding, style period, product directions, generation prompt, swatch URL. It explicitly contrasts itself with chaining palette_extract + palette_analyse + agent_brief, making differentiation from siblings immediate.

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?

States exactly when to use it: 'Use instead of chaining palette_extract + palette_analyse + agent_brief separately.' It also directs when style_context should be passed and instructs the agent to call palette_finalize if it later picks its own palette. Both the alternative and the follow-up action are named explicitly, leaving no ambiguity.

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