list_storesEvery store covered, plus card price protection. For requests like "which stores give you money back if the price drops?" or "does my credit card have price protection?". With country=GB, lists the UK policies.
| Name | Required | Description | Default |
|---|---|---|---|
| country | No | Two-letter country code. GB (or UK) lists only stores with a UK policy. Default from the request. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds scope context (it covers all stores plus card-issuer price protection policies), which is real but modest; no pagination, result count, or response-shape context is given.
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 clauses and no bloat, but the lead sentence duplicates the title verbatim rather than front-loading the operation the tool performs, so the most useful content (the example queries) is not first.
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?
The tool is simple (one optional parameter, annotations covering safety, no output schema), and the description does explain triggering scenarios and country filtering. It is still ambiguous whether the output mixes store policies and card-issuer policies, a distinction the agent needs given the sibling get_store_policy.
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 single country parameter is already fully documented, including that GB/UK limits results to UK policies. The description merely echoes the country=GB behavior, adding no syntax or meaning beyond the schema.
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 opening sentence 'Every store covered, plus card price protection' is largely a restatement of the title and never states a clean verb+resource; only the trailing clause 'lists the UK policies' hints at the listing operation. It does not distinguish this tool from sibling get_store_policy, so an agent must infer the difference from the name alone.
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 example requests ('which stores give you money back if the price drops?', 'does my credit card have price protection?') are genuinely useful routing cues for when to call this tool. However, no alternatives are named and there is no when-not-to-use guidance against get_store_policy or check_price_drop_claim.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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