get-metafield-definitions

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

No annotations are provided, so the description carries the burden. 'Discover' and 'Returns' clearly signal a read-only lookup and the description lists what comes back (namespace, key, name, type, validations), but it says nothing about pagination limits, auth/scope requirements, or what happens when no definitions exist.

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 short sentences with no filler, and the core purpose is front-loaded before the return-field list. Nothing redundant is included.

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 2-parameter read tool with no output schema, the description usefully enumerates return fields. The remaining gap is that `first` exists without any cursor argument, and the description never explains how to page beyond the max of 100 or whether results are truncated.

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% and the schema already documents both `ownerType` (with the concatenated-name normalization note) and `first` (default 50, max 100). The description only restates example owner types that the enum already supplies, adding no meaning beyond the schema; 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 and resource ('Discover custom metafield definitions') plus the scope ('for any resource type') and enumerates the returned fields. The 'definitions' framing implicitly separates it from get-metafields, but it never names that sibling explicitly, so an agent must infer the distinction.

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 implied: call this to learn what metafield definitions exist for a resource type before reading or setting values. There is no explicit when-to-use/when-not guidance and no reference to get-metafields or set-metafields, which are the most likely confusable siblings.

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