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

Annotations only declare readOnlyHint=true, so the description carries the behavioral burden and does so richly. It discloses per-colour return behavior, claim_strength scale, deduplication semantics, bundled rendered palette with downloads, and an important guardrail: never present archive anchors as recommended colours. This goes well beyond the 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?

Every sentence earns its place: core function, per-colour outputs, deduplication, invocation context, customer-facing downloads, and the palette_finalize handoff. The description is front-loaded with the tool's purpose and maintains a clear logical flow without waste.

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 full schema coverage, readOnlyHint=true, and an output schema, the description completes the picture. It covers when to use the tool, what it returns, what to show the customer, and the required downstream call to palette_finalize. Nothing essential is missing for correct selection and invocation.

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 schema already documents colours, n, and archive fully. The description loosely ties n to 'alternatives when confidence is low' and mentions hex colours and archive restriction, but adds little beyond the schema. This is an appropriate baseline when structured documentation 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?

The description clearly states the tool's specific function: 'Analyse a palette of hex colours against the Colour Memory archive' and enumerates concrete outputs like nearest named entry, cultural name, source, claim_strength, and guardrails. The instruction 'Use after extracting colours from a photo or generating a palette' distinguishes it from generation/extraction siblings and positions it in the workflow.

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 states when to call it: 'Use after extracting colours from a photo or generating a palette.' It also gives clear downstream guidance by instructing the agent to call palette_finalize if it chooses its own final palette. It does not enumerate when-not-to-use cases, but the context and sequencing are clear.

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