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

Beyond the annotations (readOnly, idempotent, openWorld, non-destructive), the description discloses 1-hour result caching with sub-5ms cache hits, per-call pricing, the 5-free-call trial, failed calls never being charged, and that exceeding quota returns a payment-required quote rather than a fatal error. These are exactly the behaviors annotations cannot express.

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?

Purpose is front-loaded in the first sentence and the labeled sections make it scannable. It is somewhat long and repeats the 5-free-call/pricing rule across the pricing paragraph and parameter guidance, which costs it a point.

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 paid, cached, read-only extraction tool with an output schema already present, the description covers cost model, cache behavior, failure semantics, and payment recovery. Nothing an agent needs in order to invoke or recover from a call is missing.

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 the baseline is 3, but the description adds real meaning: it explains the trial-vs-paid switch for agent_id/tx_hash, the agd_pass_ key format, and the retry flow after payment. It stops short of describing the store_url format beyond 'non-empty string'.

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 opening sentence names a specific verb (extracts) and concrete resources (normalized product catalogs, live prices, variants, availability) from online stores. It is immediately distinguishable from the only sibling, get_agent_wallet_status, which handles quota/balance rather than data extraction.

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?

Explicit WHEN TO USE and WHEN NOT TO USE sections state the triggering condition (deterministic shopify-spy analysis for store_url) and the exclusion (unrelated domains, binary media). It also names the alternative tool for quota checking, leaving nothing to inference.

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