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

Annotations already cover read-only/idempotent/non-destructive/closed-world, so the burden is low; the description still adds real behavior: ranking methodology, the 60%/85% eligibility thresholds, the meaning of city_rank 1, and the presence of not_ranked_reason for excluded stores.

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?

One dense sentence that is front-loaded with the core purpose and then the ranking rules. Every clause carries information, though the em-dash run-on is heavy for a single sentence.

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 no output schema, the description compensates by explaining city_rank and not_ranked_reason, which an agent would otherwise not know. The remaining gap is the undocumented limit parameter and any result-count/pagination behavior.

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 only 50%: city is documented in both places, but limit has no description anywhere. The description usefully confirms Hebrew/English/slug city formats (slug is not in the schema examples) but says nothing about limit or default/max behavior.

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 with unusual precision: cheapest supermarket branches in a city, ranked by a fixed-basket shelf-price total. It distinguishes itself from sibling price tools (chain_price_index, compare_basket_by_chain) by being city-scoped store ranking, though it never names an alternative explicitly.

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 only implied — an agent can infer this is the tool for 'cheapest stores in city X', but the description gives no when-to-use statement, no exclusions, and no routing to compare_basket_by_chain or chain_price_index, which are plausible confusions.

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