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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), and the description adds substantive behavior beyond them: unreviewed products are researched on demand from the manufacturer's page and returned with the statuses read_from_manufacturer_page (unreviewed) or unconfirmed, plus evidence and freshness are surfaced. That tells the agent to expect degraded-confidence results for off-catalog items, which no annotation conveys.

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?

The purpose is front-loaded in the first clause, followed by the returned profile and then the fallback behavior and a routing hint. The sentences are dense and occasionally long (the parenthetical standards list), but each clause carries information an agent needs; nothing is padding.

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 an output schema present, the description need not explain return values, yet it still covers accepted inputs, the research on/off mode, and the outcome statuses for unresolvable products. For a single-required-parameter identification tool with rich annotations, nothing essential 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 description coverage is 100%, so each parameter (including the role enum and the research default) is fully documented in the schema itself. The description restates the product identifier forms but adds no new syntax or format detail beyond what the schema already provides, so the baseline of 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?

The description opens with a specific verb ("Identify") and resource ("a product") and enumerates the accepted identifier forms (URL, model number, SKU, ASIN, UPC/EAN, description), which cleanly separates it from identify_from_photo and, with the closing "Use first when the product could be anything," from resolve_product/check_compatibility. It also states what the tool returns — a compatibility profile — so scope is unambiguous.

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?

"Use first when the product could be anything" gives an explicit entry-point condition, and the identifier list implies that photo-based identification belongs to identify_from_photo. However, no sibling is named and there is no stated when-not-to-use (e.g., when the product is already resolved, use resolve_product instead), so the routing guidance stops one step short of fully explicit.

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