Get price history

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

Annotations already indicate this is read-only, idempotent, and open-world. The description adds useful behavioral facts not available from annotations: the dependency on a prior get_product call and the explicit statement that extractions are not used. This goes beyond the structured metadata without contradicting it.

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?

Three short sentences, each carrying distinct value: what the tool returns, when it is available, and what it does not do. The most important prerequisite is front-loaded and there is no redundant restating of the tool name.

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 output schema, read-only/idempotent annotations, and fully described parameters, the description covers the only real gap: the state dependency on a prior get_product call. An agent has enough context to invoke this tool correctly in most situations.

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 description coverage is 100%, so both url and days are already well documented. The description's prerequisite note adds an operational constraint on the url parameter that is not in the schema, but it does not add direct detail about parameter formats or defaults.

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 identifies the resource (a product page) and what is returned (recorded price and stock changes, current/lowest/highest price). It does not explicitly contrast itself against compare_products or check_deal, but the notion of price history is distinct enough.

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 gives concrete usage context: history only exists for products CartScout has already read, and it directs the agent to call get_product first to start the history. It does not enumerate when to avoid this tool in favor of siblings, but the prerequisite guidance is clear and actionable.

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