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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered structurally. The description only adds the tenant-scoping constraint; it says nothing about pagination behavior or result shape, which the schema partly covers instead.

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 tight sentences with the resource and scope front-loaded and the filter options second; no filler or redundant restatement of the tool name.

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 simple read-only list tool with no required parameters, no output schema and full annotation coverage, the description covers what the tool returns at a conceptual level and how to narrow results. Only the behaviors already handled by annotations and the pagination schema are omitted.

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 each parameter (page, per_page, field_type, entity_type) is already documented, including the enum for field_type. The description's mention of entity/field type filters with examples (asset, work_order) largely restates the entity_type schema text, so it adds little beyond the baseline.

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 ("List custom field definitions") and adds tenant scope plus the two filterable facets. It does not name the nearby siblings (get_custom_field_definition, list_custom_field_values), so an agent must infer the boundary itself, but the purpose is unambiguous.

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?

Filtering is described ("Filter by entity type ... or field type"), which implies when the tool is useful, but there is no explicit when-to-use/when-not guidance and no mention of alternatives such as get_custom_field_definition for a single definition or list_custom_field_values for values.

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