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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered structurally. The description adds real value beyond those annotations by naming the required OAuth scope (custom_fields:write), which an agent needs before attempting the call. It stops short of stating what happens to dependent data or whether the delete is soft or hard.

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, front-loaded with the action and immediately followed by the authorization requirement. No filler or redundancy.

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 single-parameter destructive delete with rich annotations, the description supplies the missing piece (required scope). Nothing critical is absent, though a note on irreversibility or effect on parent records would fully complete it.

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% with a single documented id parameter (UUID format and pattern fully specified). The phrase 'by ID' adds nothing beyond the schema, so the 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 states a specific verb (Delete) and resource (a custom field value) plus the identifier method (by ID), which is clear. It does not differentiate from its nearest sibling delete_custom_field_definition, which deletes the definition rather than a value, so an agent must infer the distinction from the tool names alone.

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 no when-to-use guidance, prerequisites beyond the scope string, or alternatives. An agent looking at delete_custom_field_definition, update_custom_field_value, or get_custom_field_value gets no routing help.

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