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

With no annotations, the description carries the full burden and handles it well: it discloses variable coverage, that these are advertised rather than verified purchase quotes, that every price carries observed_at and expires_at, and that quoting after expires_at is prohibited. What is missing is auth requirements, pagination or result-size behavior, and latency/cost expectations.

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, front-loaded with what is returned before the caveats and the freshness rule. Every sentence carries distinct information — payload, data-quality caveat, staleness rule — though the opening sentence is dense and slightly awkward to parse.

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?

There is no output schema, so the description must describe return content, and it does: min/max/median, 30 and 90 day lows, plus observed_at/expires_at per price. Combined with the data-fidelity caveat, an agent has enough to call and interpret it, though the shape of the returned record set and edge cases (no coverage for a product) go unaddressed.

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?

Only one parameter, and schema coverage is 100% — the schema already explains product_id as a canonical product uuid sourced from search_products. The description's 'for one product' merely restates the singular scope without adding format or sourcing detail beyond the schema. 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?

The description names the resource (dated advertised retailer observations for one product) and specifies exactly what is returned: min, max, median, and 30/90 day lows. An agent knows this is an aggregated comparison view rather than a raw listing. It does not, however, name or contrast with the obvious siblings get_current_prices or get_price_history, leaving that distinction to inference.

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?

Usage is implied rather than stated: 'these are not exact-variant verified purchase quotes' hints that a verified-offer sibling should be used when exactness matters, and 'do not quote after expires_at' gives a hard validity rule. But there is no explicit when-to-use or when-not-to-use statement and no sibling is named, so the agent must infer the routing.

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