Find cheapest product

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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, but the description adds substantive behavior beyond them: the site search also matches descriptions, so titles containing every query word are kept by default; variable products are listed at their cheapest variant only; and pagination is signaled via a 'complete' flag. This is meaningful operational context an agent could not derive from the schema alone.

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?

Front-loaded with the core purpose, then usage, then the two edge-case behaviors. Every sentence earns its place, though the third paragraph's edge-case detail is dense enough that it slightly dilutes the crisp opening.

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 return values need not be explained, and the description covers the remaining gaps: filtering default, variable-product handling, and the scan/complete continuation loop. An agent has everything needed to call this correctly.

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, and the description adds real value on top: it gives the currency (Toman), explains the sorted-by-current-price ordering, and ties the 'complete' output to the 'scan' parameter. It doesn't restate limit/match_all_words, but that is precisely because the schema already covers them.

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+scope ('Find the cheapest in-stock products for a keyword, one flat list sorted by current price'), which is instantly distinguishable from generic siblings like ab_search. The 'cheapest' framing pins down the differentiator without needing to open the 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?

Explicitly says when to use it ('Use when the user wants the lowest price for X') and routes to the alternative for a related need ('check ab_product for the size you need'). It even documents the failure/continuation condition ('complete=false means more in-stock matches lie past scanned: raise scan'), leaving little to inference.

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