opensea_item_chart

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

With no annotations provided, the description carries the full behavioral burden. It handles the important edge case of an item that has never sold, returning an empty `points` list, and discloses exactly what is returned (timestamps, token price, USD price). It does not mention auth or rate limits, but for a read-only retrieval tool the core behavior is clearly presented.

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 three sentences with no filler. The purpose is front-loaded, the return behavior is summarized in the second sentence, and the collection-level alternative is stated clearly in the third. Every sentence earns its place.

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?

For a simple 3-parameter tool with no output schema, the description explains the shape and content of the return (`points` with timestamp and price) and the empty case, which is enough for an agent to invoke the tool correctly. It does not specify exact JSON formatting, but that is acceptable given the low complexity and the coverage of input schema.

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 100% description coverage for all three parameters (chain, contract_address, token_id), and the tool description does not add new parameter-level meaning beyond what the schema already provides. This matches the baseline of 3 when the schema carries the weight.

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 a precise action and subject: 'Get an OpenSea NFT's sale-price history.' It goes beyond a generic statement by specifying returns (timestamps, prices in token and USD) and explicitly distinguishes item-level from collection-level history, which differentiates it from siblings like opensea_collection_chart and opensea_activity.

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 directly says what this tool is for (per-NFT sale-price history) and gives an explicit alternative for collection-level history with an endpoint path. This informs an agent when not to use the tool and routes the selection to a different call.

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