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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely non-derivable behavior: the response is 'signed' and its payload is tiered, with ingredients, claims, attributes, shades and offers only returned 'after the gate'. That gate-dependent variability is exactly the kind of context an agent needs before calling.

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?

A single semicolon-chained run-on carrying three distinct ideas (source/signing, hub scope, tiered return fields). Front-loaded acceptably, but the long comma-separated field enumerations add bulk and would be better delegated to the output schema.

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?

An output schema exists, so the extensive listing of return fields is largely redundant and does not offset the missing parameter meaning. The gate prerequisite is hinted but never explained (what unlocks the gated fields, what happens if the gate is not passed).

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% for all three parameters. The description partly compensates for 'gtin' ('One product by GTIN'), but 'market' and especially 'decision_id' are left completely unexplained in both schema and description, leaving the agent to guess their role.

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 verb+resource ('Product record ... One product by GTIN, fully resolved') and positions itself as the 'hub layer' that aggregates the narrower siblings (price, availability, claim, market). The dense field list makes the scope readable, though 'hub layer' is insider jargon that requires 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: the tool is framed as the comprehensive one-product lookup versus the granular siblings, and 'after the gate' hints that gate_transaction must run first. No explicit when/when-not or named alternative (compare_items, search_cleared_items) is given.

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