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

With no annotations, the description carries the full burden. It does disclose the shape of the returned data (min, max, average, direction of travel), which is genuinely useful. It does not state read-only safety explicitly, what happens when a product has no recorded price history, or how sparse/partial windows are handled.

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 sentences, front-loaded with what the tool returns before the usage framing. Little waste, though the quoted user questions are slightly conversational padding for an agent-facing definition.

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 two-parameter read tool with full schema coverage and no output schema, the description covers what the tool does and roughly what comes back. The main remaining gap is behavior on empty or insufficient history, which matters for a history-reading 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%, so both the id and the days enum (7/30/60/90, default 30) are already fully documented. The description's 'trailing window' phrasing echoes the days parameter but adds no syntax or edge-case detail, so the baseline 3 applies.

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?

States the resource (recorded price points for a product) and the trailing-window scope, plus the aggregate fields returned. It is clear what the tool produces, but it never names or distinguishes itself from siblings like get_price_verdict or get_price_index, which sound like they cover adjacent questions.

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 second sentence gives implied usage context ('is now a good time to buy', 'has this got cheaper'), which is more than nothing. However, there are no exclusions, and the stated use case plausibly overlaps with the sibling get_price_verdict, so the agent gets no routing rule for choosing between them.

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