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

Annotations only declare readOnlyHint=true, and the description adds meaningful behavioral context: it turns absence of evidence into a forensic finding, returns support levels (supported/partial/unsupported), and provides safe agent wording. This goes beyond the annotation without contradicting it.

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 front-loaded with the core behavior and is about five sentences long. The example is helpful, though the output list is partly repeated between the first sentence and the example, making it slightly less concise than it could be.

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?

The description covers the tool's purpose, output, and target workflows. Given that an output schema exists, it does not need to enumerate return fields in detail. It lacks explicit sibling differentiation and limitations, but overall provides enough context for an agent to select and use the tool.

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 a concrete example ('#4A535C' + 'cyanosis in a death chamber') and explains the intent of proposed_claim, but it does not add new parameter-level syntax or constraints beyond the schema.

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 opens with a specific verb ('return') and precisely names both inputs ('hex value' and 'proposed claim') and outputs (support decision, missing evidence, source type, safe wording). It also positions the tool as Colour Memory's anti-hallucination endpoint, clearly distinguishing it from siblings like archive_search or archive_coverage_gap.

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 states the tool is 'essential for museum, documentary, editorial, legal, and forensic workflows' and gives an example scenario. It implies use when an agent has a proposed claim about a colour and needs evidence validation, but it does not explicitly name alternatives or state 'when not to use'.

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