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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond them: resolution rules (case-insensitive, exact match wins, otherwise substring), explicit error behavior that returns candidate ids on ambiguity, currency (USD), and the critical `published: false` caveat that values are vendor wording and must never be estimated from. That last point is a genuine behavioral warning not derivable from any structured field.

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?

It is one dense, front-loaded block with no filler — return shape first, then matching rules, then error behavior, then the pricing caveat. The middle enumeration of record fields is long but each field is load-bearing given there is no output schema. Slightly heavy as a single paragraph, but nothing is redundant.

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 carries the full burden of describing `matches` and `records` — and it does, down to nested `plans`, `rates`, `free`, `overage`, `gotchas`, `sources` and `checked`. Combined with the ambiguity/error path and the `published` caveat, an agent has everything needed to call this correctly and interpret the result.

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?

With 100% schema coverage the baseline is 3, and the description adds real semantics for `tool_id`: case-insensitive, exact-match-wins-then-substring resolution, with concrete example values. It does not explain the `dataset` parameter's disambiguation role in the description text (the schema handles it), which keeps it just short of a 5.

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 opens with a specific verb and resource: 'Read-only full verified record for one product,' and the return-shape enumeration makes it unmistakable versus siblings like list_tools (enumeration) or compare_tools (multi-product comparison). An agent can distinguish this from all five siblings without opening a schema.

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: it says to match 'by id (e.g. "claude", "cursor"...)' or by name, and that ambiguous/unknown names error with candidate lists, which tells the agent how to recover. But there is no explicit when-to-use-this-vs-alternatives statement (e.g. 'use list_tools first to discover ids', or 'use compare_tools for multiple products'); list_tools only appears in the schema, not the description.

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