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

Annotations only cover the safety profile (readOnly, non-destructive, closed-world), but the description adds substantive behavior: the verification criteria that qualify a deal, the 48h re-check window, several days of readings required, new-condition-only and Amazon-only scoping, and that each result carries its proof (reference price, period, reading count). That is exactly the extra context annotations cannot convey.

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?

Front-loaded with the core noun phrase and then compressed into a single dense sentence of qualifying criteria plus one sentence on returned proof and one on filtering. Nearly every clause carries selection-relevant meaning, though the criteria stack is heavy enough that a bulleted split would read faster.

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?

With no output schema, the description compensates by naming what each deal returns (reference price, period, reading days) and by bounding the data's freshness and condition scope. Combined with a fully documented two-parameter schema and read-only annotations, an agent has everything it needs to call this correctly.

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 limit and query are already documented with an example. The description only restates that filtering by words in the product name is optional, adding no syntax, matching rules, or default-value information 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?

States a specific resource ('current verified price drops') and defines it operationally: the SAME offer cheaper than its own 90-day lowest recorded price, backed by multiple reading days, re-checked within 48h, new condition, Amazon offers re-verified. That definition is unique against get_price_history (historical series) and search_products (general search), so an agent can route correctly even without the siblings being named.

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: 'Current verified price drops' tells the agent this is for spotting live bargains, and the query filter explains one narrowing option. However, it never says when to prefer this over get_price_history (e.g. to inspect the underlying readings) or search_products, and no exclusions or prerequisites are given.

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