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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful context: results are bucketed by a single letter/digit, entries are linked to retailmenot_store, and a regional market variant exists. It omits pagination, result-size, or rate-limit behavior, which is acceptable given the annotations carry the safety signal.

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?

Three short sentences, front-loaded with the core purpose followed by usage and parameter guidance. Efficient overall, with only mild awkwardness in the "with domains for retailmenot_store" clause.

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 detailed. The description covers purpose, when to use it, both parameters, and the cross-relevant sibling, leaving no gap an agent needs to call it 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?

With schema description coverage at 0%, the description does the compensating work: it defines the letter parameter's valid domain (a-z or 0-9) and explains the market parameter's semantic (market=ca selects RetailMeNot Canada). Both parameters are meaningfully described beyond their bare schema types, a solid job on a two-param tool.

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 ("List") and resource ("every store in one letter... of RetailMeNot's A-Z store directory"), and the letter-bucketed scope distinguishes it from the sibling retailmenot_store. The mention of "with domains for retailmenot_store" clarifies its relationship to that sibling, though the phrasing is slightly opaque about whether it returns store domains or store objects.

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?

Gives a clear selection condition: "Use to browse stores when no search term is known," which routes the agent away from search-style tools toward this browse tool. It doesn't explicitly name an alternative search tool, but the no-search-term condition is an actionable when-to-use signal.

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