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

Annotations already flag destructiveHint and idempotentHint, but the description goes well beyond them: it explains that values are retained under the key, that the dashboard hides them, that the AI stops collecting within a minute, and that built-in fields return 422. This is exactly the kind of ordering/side-effect context an agent cannot infer from annotations.

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 the action verb, then layered with consequences and failure mode in tight sentences. The repeated title line is the only redundancy and is negligible.

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, and the description fully covers the mutation's effects, timing, reversibility, and error behavior. Nothing an agent needs to invoke 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 description coverage is 100%, with both agent_id and field_key fully documented including their error codes. The description adds behavioral context (custom_fields, key persistence) but no new parameter semantics, so the baseline 3 applies.

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+resource (delete a lead field) and adds scope detail about what is removed. It is clearly distinguishable from create_lead_field, update_lead_field, and delete_lead among siblings.

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 makes the deletion context clear and implicitly excludes built-in fields via the 422 system_field rule, telling the agent when the call will fail. It does not explicitly route to alternatives like update_lead_field for non-destructive changes, so no full when-to-use-this-vs-that guidance.

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