list_field_choices

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

With no annotations, the description carries the full burden and delivers a critical hidden behavior: for cf_* fields a numeric id is silently ignored with a 200 response and no error or change. Disclosing this silent-failure mode is exactly the kind of behavioral context an agent cannot infer from the schema.

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?

Front-loaded with purpose and usage, then the critical IMPORTANT caveat. The text is dense but every clause earns its place; the parenthetical detail about silent failure is justified by its impact on correctness.

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 2-param lookup with no output schema, the description covers purpose, when-to-use, the module enum context, field naming, the return shape (id -> label), and the input-type gotcha. Nothing an agent needs to call it correctly is missing.

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 coverage is 100% and both params are documented, but the description adds meaning beyond the schema: the rule that built-in fields take the numeric id while cf_* fields take the label STRING. This distinction is not derivable from the schema and directly affects correct invocation.

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 (look up) and resource (a field's definition and valid dropdown choices) with concrete scope including custom fields (cf_*). This is clearly distinguished from the CRUD siblings (create_deal, update_lead, etc.), which mutate records rather than resolve field metadata.

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?

Explicitly says when to use it ('before setting a dropdown/custom_field value you don't already know the id for') and provides a worked example (module="deals", field="deal_stage_id"). The condition that selects this tool is unambiguous.

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