getHistoricalDowJonesChanges

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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the description's mention of 'Access historical data' aligns with these traits. The description adds value by specifying the nature of the data (composition changes, performance), but does not contradict annotations or reveal additional behaviors beyond what annotations imply.

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 concise sentences that front-load the action ('Access historical data') and efficiently convey the tool's purpose and capabilities with no extraneous 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?

The description covers both primary aspects (composition changes and performance) of the return value despite having no output schema. It is sufficiently complete for a read-only, parameterless tool, though a bit more specificity about the output format would improve completeness.

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?

The input schema has zero parameters, so the description carries no parameter burden. Per guidelines, baseline is 4. The description does not attempt to describe parameters (none exist), so it meets the minimum expectation.

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 accesses historical data for the Dow Jones Industrial Average, including composition changes and performance. The tool name already differentiates it from siblings like getHistoricalSP500Changes, but the description does not explicitly contrast them, leaving some ambiguity among the many similar historical index tools.

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?

No guidance is provided on when to use this tool versus alternatives like getHistoricalSP500Changes or getHistoricalNasdaqChanges. The description does not mention prerequisites, context, or exclusions, leaving the agent to infer usage solely from the tool name.

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