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

With no annotations, the description carries the full burden and does well: it discloses the $0.01 USDC cost, the read-only nature of the operation, and the null semantics for shipping, tax, and unknown values. It does not cover failure modes or rate limits, but the core behavioral traits are transparent.

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 short sentences with no filler. The cost, target resource, timing, null-value behavior, and non-purchase guarantee are all packed in efficiently and front-loaded.

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?

The description covers the core purpose and cost, but without an output schema or annotations it leaves gaps around return shape, failure behavior, and how the nested parameters interplay. It is adequate for basic use but not fully complete.

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 0% and the description adds little parameter-level meaning. It indirectly references the URL as a public HTTPS product page but says nothing about how variant, quantity, or destination affect the quote.

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 action and resource: 'Retrieves explicitly published product price and stock from a public HTTPS product page.' It also clarifies its role as a pre-purchase quote with 'Never purchases,' which helps distinguish it from purchase or transaction tools.

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?

Provides clear usage context: use it 'before an agent buys.' It also explicitly excludes purchasing behavior. However, it does not name sibling alternatives or state when not to use this tool beyond not purchasing.

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