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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior the annotations cannot convey: the tool returns fundamentally different result sets depending on whether slug is present. It does not mention pagination limits on results or freshness/caching of 'live' data, which keeps it from a 5.

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?

Two sentences, no filler. The identity of the resource is front-loaded, followed immediately by the mode split, which is the most decision-relevant information for an agent.

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 shapes need not be described, and the description covers both invocation modes adequately for a 2-parameter read-only tool. Minor gaps remain around result volume/pagination and whether the sale list is time-bounded, but nothing essential to a correct call 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 coverage is 100%, so both parameters are already documented, giving a baseline of 3. The description earns above baseline by explaining the semantic consequence of slug — it switches the tool from listing sales to listing the products whose prices dropped in that sale — which the schema's 'sale slug from a previous sale_events call' does not make clear.

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 names a specific resource ('live retailer sale events tracked by CheapestInIndia') and gives concrete examples (Big Billion Days, Great Indian Festival), so the agent knows exactly what data domain this covers. It also distinguishes its two operating modes. It does not explicitly contrast itself with near siblings like top_price_drops or brand_price_drops, so it stops short of a 5.

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 structurally: call without slug to enumerate sales, call with slug to drill into a sale's price-dropped products. That is a useful mode-selection rule, but there is no explicit guidance on when to prefer this over top_price_drops or brand_price_drops, and no stated prerequisite that a slug must first be obtained by a listing call.

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