Get Price History

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

Annotations already indicate read-only and idempotent behavior. The description adds valuable behavioral details: downsampling to at most 60 data points, cents-to-USD conversion, and decoding Keepa time to ISO dates. This goes beyond annotation coverage.

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 well-structured and front-loaded: main purpose, return data, unit/time conventions, args, and examples. Every section earns its place with no redundancy or fluff.

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?

Despite having no output schema, the description explains what data points are returned and the format. Combined with strong annotations (read-only, idempotent, non-destructive), it gives a complete picture for a 3-parameter read 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 covers all parameters (100% coverage), so baseline is 3. The description adds concrete examples for range values and clarifies domain default, which helps the agent map natural language to parameter values.

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 states the specific action ('Fetch historical price data') on a specific resource ('Amazon ASIN from Keepa') and clearly lists the returned data series. It distinguishes itself from siblings like get_product (product info) and get_sales_rank_history (sales rank), though not explicitly.

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?

Provides clear context through examples and parameter descriptions, showing when to use (e.g., 'Show price history for B08N5WRWNW over the past year'). Does not mention alternative tools or exclusions, so it's not a 5, but it's more than implied usage.

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