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

Annotations already declare readOnlyHint=true, and the description adds behavioral context by stating the output is 'dated sequence', 'chronological order', and includes 'primary sources.' The example with 'indigo' illustrates the multi-century scope, giving agents a clear model of how the tool behaves.

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 compact and well-structured: first sentence states the action and output, second gives usage scenarios, third provides an illustrative example. No redundant words, and each sentence adds distinct value.

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 tool has a good output schema and read-only annotation. The description covers functionality, usage, and parameter semantics with an example that ties everything together. For a tool of this complexity, it is fully self-contained and leaves no critical gaps.

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% for both parameters, so the baseline is 3. The description enriches the 'concept' parameter by providing concrete examples ('indigo', 'imperial purple', 'mourning black'), which helps agents understand what constitutes a valid input beyond the schema's generic description.

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 function with a specific verb ('traces') and resource ('documented appearances across cultures and centuries'), and specifies the output format (dated sequence of archive entries with primary sources). This distinguishes it from sibling tools like archive_provenance or colour_story, which likely focus on different aspects of history or narrative.

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 lists use cases: 'historical research, provenance chains, and understanding why a colour carries the cultural weight it does.' While it doesn't name alternative tools or state when not to use it, these concrete scenarios provide clear guidance for when to invoke this tool.

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