create_metafield_definition

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

No annotations are provided, so the description must disclose behavioral traits. It states the tool creates a definition at the store level and mentions validations, but it does not disclose whether the operation is idempotent, what happens if the definition already exists, required permissions, or any side effects. This is minimal disclosure.

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?

The description is three sentences long. The first sentence states the purpose, the second explains what definitions do, and the third provides a usage hint for validations. No unnecessary words or repetition, making it concise and front-loaded with key information.

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?

Given 8 parameters, 3 required, no output schema, and no annotations, the description is adequate but not thorough. It covers the core purpose and validations but lacks prerequisites, permissions, idempotency, or return value hints. It is sufficient for a straightforward creation tool but leaves gaps.

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?

The input schema has 8 parameters with 100% description coverage, so the schema already explains each parameter. The description adds brief extra context for validations ('e.g. allowed choices for text fields') and mentions the 'validations' parameter, but this does not significantly surpass the schema details. Baseline 3 is appropriate.

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 'Create a new metafield definition for products at the store level.' It uses a specific verb ('create') and resource ('metafield definition'), and distinguishes from sibling tools like list_metafield_definitions or delete_product_metafield by focusing on creation and definition-level structure.

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 gives context for validations ('Use `validations` to set constraints like allowed choices for text fields.'), implying when to use the tool (to define structure before assigning metafields). However, it does not explicitly state when not to use this tool or mention alternatives, so guidance is implied but not explicit.

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