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

Annotations declare destructiveHint=true, so the safety burden is partly lifted, and the description usefully frames the operation as an additive schema change and gives the endpoint. However it never states whether the write is irreversible, whether the property name must be unique, or how existing contacts are affected — the exact context the destructive hint begs for. Note the mild tension between 'additive' and destructiveHint=true, which may reflect irreversibility rather than data loss.

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 resource, with no padding. The endpoint restatement is compact and cheap.

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?

No output schema exists, so return values need not be explained, and both params are fully covered by the schema. Still missing is the behavioral context an agent needs for a schema-mutating write — uniquenes constraints, reversibility, and when creation is appropriate.

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 both parameters (name, type) are documented in the schema with an enum for type, so the baseline is 3. The description adds no format, uniqueness, or naming-convention detail beyond what the schema already provides.

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 ('Creates a custom contact property/field') and adds scope qualifier ('additive schema change'), which cleanly separates it from loops_list_contact_properties and loops_delete_contact. An agent can tell what this does 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?

There is no when-to-use guidance, no alternative named, and no precondition stated (e.g. check list_contact_properties for an existing definition first). The '(additive schema change)' parenthetical implies a mutation context but does not route the agent to a sibling.

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