custom_fields_search

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the trailing 'read-only' is largely redundant. The description does add real context beyond annotations by explaining that dynamic values surface via stable named properties and extra_fields arrays, but it discloses nothing about auth scope, result limits, or pagination behavior.

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?

Compact and front-loaded: the resource scope leads, then the resource_type instruction, then the output-shape note. The one wasted sentence is the closing 'This tool is read-only', which repeats the annotation and the opening verb.

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?

An output schema exists, so return values need not be described. However, for a 7-parameter search with 0% schema coverage, key filters like action_name, item_id, and query are left completely unexplained, so the definition is only partially complete for correct invocation.

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 0% across 7 parameters, so the description carries the full burden and mostly fails. It only addresses resource_type, and notably leaves action_name (default 'list') and fieldset_id undefined, which are central to how the search is scoped.

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 states a specific verb (read/search) and resource (custom fields, fieldsets, db_column identifiers, validation metadata, fieldset membership), and the final clause 'read-only' cleanly distinguishes it from the custom_fields_write sibling. An agent can tell what it returns without opening the schema.

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?

It gives one operational hint ('Use resource_type=field or fieldset'), which is genuinely useful for selecting the resource class. But it offers no when-to-use guidance relative to the many sibling search tools (catalog_search, inventory_search, etc.) and no exclusions or prerequisites.

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