get_categoriesGet available product categories and the approximate price range for each. Use to guide the user when their request is vague.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
| currency | Yes | ||
| providers | Yes | Retailers currently enabled. WEM compares only feeds it is licensed to use. | |
| categories | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is known. The description adds the 'approximate price range' detail, which is behavioral info beyond annotationsscrib. No contradictions.
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: first states what the tool does, second gives usage guidance. No fluff, front-loaded.
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 parameters, an output schema exists, and read-only annotations, the description provides the essential purpose and usage context. It mentions price range which adds value. It's complete for a simple listing tool.
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?
No parameters exist, so schema coverage is 100% by definition. Baseline is 4, and the description adds no parameter info (not needed).
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 clearly states the tool lists product categories with approximate price ranges, using specific verbs ('Get') and resource ('product categories'). It's distinct from siblings that focus on offers, products, prices, or searches, so differentiation is clear.
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 description explicitly says 'Use to guide the user when their request is vague,' giving a clear context for when to invoke this tool. It doesn't mention alternatives or when not to use, but the usage condition is specific enough.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct action: searching, semantic searching, retrieving categories or product details, comparing offers, comparing products, finding a single lowest price, and verifying a claim. The only mild ambiguity is between search_products and semantic_search, and between compare_offers and find_lowest_price, but the descriptions provide enough separation for an agent to choose correctly.
Most tools follow a clear verb_noun pattern such as compare_offers, get_product, search_products, and verify_offer. The main deviation is semantic_search, which is adjective_noun rather than verb_noun, making it the one inconsistent name in an otherwise predictable set.
Eight tools is a well-scoped size for a price-comparison server. Each tool covers a meaningful part of the workflow without redundancy or unnecessary breadth.
The toolset covers product discovery, category browsing, detailed product retrieval, multi-offer comparison, side-by-side product comparison, lowest-price recommendation, and price-claim verification. The main gap is the lack of a dedicated price-history tool, even though a 90-day price low is referenced in compare_offers, but this is not a blocking omission for the core comparison workflow.