Metafields Create

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

Annotations already declare the mutation profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), and the description usefully adds the required OAuth scopes per owner_resource plus the pinned API version. It says nothing about the failure mode an agent most needs — what happens when a metafield with the same namespace/key already exists (error vs. overwrite) — so the non-idempotent hint is left unexplained.

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?

Four short, front-loaded lines with zero padding: purpose, endpoint, scope, version. The scope line is dense but each element is actionable, and nothing is repeated from the schema.

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 7-parameter write tool with no output schema, the description covers identity, auth, and API version but leaves out the return payload and duplicate-key behavior. The nested additional_fields escape hatch is also unaddressed, so an agent cannot tell when the typed parameters are insufficient.

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 the baseline is 3; the description earns an increment by mapping owner_resource enum values to the scopes they require (products: Product/Product_Variant/Category, content: Page, and so on), which the schema does not express. It adds no guidance on the value field's expected format for structured types, which is the other ambiguity in 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?

States a specific verb and resource ("Create a metafield") and pins it to an HTTP endpoint, which cleanly separates it from the metafields_get/update/delete siblings. It does not, however, distinguish metafields from the adjacent tiendanube_custom_fields_* family, which an agent could easily confuse.

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?

There is no statement of when to use this versus tiendanube_metafields_update (e.g., whether an existing namespace/key should be updated instead) or versus tiendanube_custom_fields_create. The only directional content is a required-OAuth-scope list, which is a prerequisite, not usage guidance.

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