Create or update up to 25 metafields atomically on any Shopify resource, including products, orders, customers, variants, and collections.
Set metafields on any Shopify resource (products, orders, customers, variants, collections, etc.). Creates or updates up to 25 metafields atomically.
| Name | Required | Description | Default |
|---|---|---|---|
| metafields | Yes | Metafields to set (max 25). Works on any resource: products, orders, customers, variants, collections, etc. |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it delivers the key traits an agent needs: create-or-update (upsert) semantics, atomicity across the batch, and a hard cap of 25. It omits permission/scope requirements and what the response reports (which metafields were created vs. updated).
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, front-loaded with the capability and followed by the behavioral qualifier. No repetition of the tool name, no filler.
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?
For a single-parameter mutation tool with no annotations and no output schema, the description covers the essentials: scope, upsert behavior, atomicity, batch limit. The remaining gap is return-shape and error/partial-data expectations, which are not covered anywhere else.
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 ownerId/key/value/type/namespace are fully documented in the schema. The description only restates the 25-item max that the schema already declares, adding no format or semantic detail beyond it. Baseline 3 applies.
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 ('Set') plus resource ('metafields') and explicitly broadens scope to any Shopify resource (products, orders, customers, variants, collections). The atomic-upsert and 25-item cap sharpen the picture. It never names its siblings (get-metafields, delete-metafields) to draw the contrast, 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 only implied: an agent can infer this is the write counterpart to get-metafields/delete-metafields. There is no explicit when-to-use, no when-not, and no prerequisite guidance (e.g. that 'type' is needed when no definition exists, or that this is the bulk path vs. per-resource endpoints).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.