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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the bar for additional context is lower. The description adds valuable behavioral detail: returns up to 5 curated SKUs ranked by fit, with price, stock, URL, and cart-continuity fields, and explains free-text mapping for use_case. This goes beyond structured data and informs expected output and flexibility.

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 description is two sentences long, front-loaded with the trigger condition and required arguments, followed by the output specifics. Every sentence adds functional value; there is no fluff or redundant context.

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?

Given there is no output schema, the description compensates by explaining the return shape (up to 5 curated SKUs with price, stock, URL, and cart-continuity fields) and the free-text use_case behavior. It does not address no-match scenarios, but the sibling tool explain_no_exact_match likely covers that, making this sufficiently complete for a read-style tool.

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 the baseline is 3. The description repeats the use_case canonical values and free-text mapping exactly as in the schema, and lists all parameter names, but adds no new semantics beyond the schema. The parameters are self-explanatory, so this is adequate but not enhanced.

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 clearly identifies the tool's purpose: find packaging for an item based on dimensions. It uses a specific verb ('find') and resource ('packaging for an item'), and distinguishes itself from siblings like check_inventory or get_pricing by focusing on dimension-based fit ranking. The title and first sentence together make the scope 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?

The description explicitly states when to use the tool: when the buyer has item dimensions and needs a fitting box or mailer. It does not name alternative tools or exclusions, but the condition is clear and practical. A stronger version would contrast with pack_calculator or search_products, but the given guidance is sufficient for a competent agent.

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