reach_updateAContactFieldV1

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

With no annotations provided, the description carries the full burden. It transparently discloses destructive behavior: 'any existing option left out of the list is deleted along with the values contacts hold for it,' and also notes immutability of field type/slug. This gives clear insight into side effects, though it omits details like required permissions or error conditions.

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 two concise sentences, front-loaded with the primary purpose. The second sentence provides essential nuances about option replacement and constraints without unnecessary detail, making it efficient and well-structured.

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?

The tool has 4 parameters and complex option replacement behavior. The description covers the key semantics, constraints, and destructive consequences, providing enough context for correct invocation. It lacks explicit return value information, but given no output schema and the nature of update operations, this is not a major gap.

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?

The schema has 100% coverage with minimal descriptions (e.g., 'label parameter'), baseline 3. The tool description adds meaning by explaining that 'label' is the new name via 'Rename a custom contact field,' and the options parameter's replacement semantics are emphasized in both schema and description. This enriches understanding beyond the schema's terse labels.

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 the tool's action: 'Rename a custom contact field and, for the choice types, replace its option set.' It identifies the specific verb (rename/replace), resource (custom contact field), and scope (option set), making it distinct from sibling create/delete/list operations.

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 implies when to use the tool (needing to rename a field or replace its option set) and provides an exclusion by stating 'The field type and slug cannot be changed.' However, it does not explicitly mention alternatives like reach_createAContactFieldV1 or reach_deleteAContactFieldV1, so it falls short of full explicit guidance.

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