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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds genuine value beyond them: the failure is silent, no error is raised, and live campaigns will send with an empty hole. That is the exact consequence an agent needs to know before invoking. It stops short of stating recoverability or whether the deletion can be undone.

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 warning is well front-loaded right after the verb, but the silent-failure point is restated three times ("render it empty — silently", "nothing fails", "the sends just go out wrong"), which costs a sentence without adding information.

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 one-parameter destructive tool with no output schema, the description covers what is destroyed, the failure mode, the safety workflow, and the alternative tool. Nothing an agent needs to call this safely 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 the single parameter's description already points to `placeholder_list` as the source of the id. The description adds no format or validation detail beyond the schema, 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?

The description opens with a specific verb and resource: "Remove a merge field." It is immediately distinguishable from the sibling tools `placeholder_add` and `placeholder_list`, which are named later, so an agent can route correctly without inspecting 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?

It gives an explicit precondition workflow (search sequences for the key, show the user, get an explicit yes) and names the alternative for a different intent (`placeholder_add` to change fallback text instead of deleting). When-to-use, when-not-to-use, and the substitute are all present.

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