getHistoricalSectorPerformance

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

Annotations already provide readOnlyHint, idempotentHint, and openWorldHint, which cover the safety and side-effect profile. The description adds no behavioral traits beyond stating it accesses historical data. No conflicts with annotations.

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 a single sentence and gets the point across. It includes a slightly redundant phrase 'using the Historical Market Sector Performance API' which could be omitted, but overall it is concise and well-front-loaded.

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 the tool has 4 parameters (1 required), annotations present, and no output schema, the description is adequate but could be more complete. It does not mention what the response looks like (e.g., data granularity, time periods) or any important usage notes. Still sufficient for a simple data retrieval 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 coverage is 100% with descriptions for all 4 parameters. The description does not add any additional meaning beyond what the schema already provides. Baseline 3 is appropriate.

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 retrieves historical sector performance data and mentions 'over time across various stock exchanges', which distinguishes it from sibling tools like getSectorPerformanceSnapshot (likely current data). The verb 'Access' and resource 'historical sector performance data' are specific.

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 implies usage when historical data is needed (due to 'historical' in name and description), but it does not explicitly state when to use this tool versus alternatives like getHistoricalIndustryPerformance or getSectorPerformanceSnapshot. No prerequisites or exclusions are mentioned.

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