getHistoricalMarketCap

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

Annotations already declare the tool as read-only, idempotent, and open-world. The description adds no additional behavioral traits beyond stating it 'accesses' data, which is already clear from annotations. No contradictions.

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?

Two sentences, front-loaded with the action and resource. Each sentence adds value: first states what it does, second explains the application. No wasted words.

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 4 parameters, no output schema, and rich annotations, the description is sufficiently complete. It explains the API's purpose and typical use case. Could optionally mention that results are paginated or date-range behavior, but not necessary.

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?

Input schema covers 100% of parameters with their descriptions. The description adds no extra semantic meaning beyond what the schema provides, so baseline score of 3 applies.

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 verb 'Access' and the resource 'historical market capitalization data'. It distinguishes from siblings by mentioning 'historical' and 'over time', contrasting with the sibling tool 'getMarketCap' which likely provides current data.

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 provides context for usage ('long-term assessments of growth or decline'), but lacks explicit guidance on when not to use or alternatives. While it implies historical vs. current, it doesn't state that for real-time data you should use 'getMarketCap' or other tools.

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