create_a_custom_field_relationship_to_lists

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

Annotations indicate this is a write operation (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds value by stating the HTTP method (POST) and that the operation is reversible, which is beyond the annotations. No contradictions.

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 very concise: two sentences plus a compact header with category and HTTP method. Every part adds value, and it is front-loaded with important metadata.

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 no output schema, the description explains the operation well, including examples and reversibility. It could mention response format or error handling, but the current content is sufficient for a write tool with high schema coverage.

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%, so baseline is 3. The description adds meaning by explaining the effect of the operation (associates records) and providing examples, which helps understand the 'field' and 'relid' parameters beyond their schema descriptions.

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 that the tool creates a custom field relationship to lists, and it differentiates itself from siblings like 'delete_a_custom_field_relationship_to_lists'. Examples (tags a contact, adds to list/automation) further clarify the purpose.

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 provides usage context with examples and mentions reversibility, but does not explicitly state when not to use the tool or suggest alternatives. Given the large sibling set, this is adequate.

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