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

Annotations already flag destructiveHint=true, but the description adds genuinely non-obvious blast-radius information: only the default pointer is cleared and existing channels keep their captured values. It also discloses the response shape (status CLEARED with listId, provider, and name nulled, or an error), which is unavailable elsewhere since there is no output 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?

Two sentences, zero filler. The action and its scope lead, followed immediately by the non-destructive detail about existing channels and the return contract.

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?

With no input parameters and no output schema, the description carries the full load and does so: it covers effect scope, side-effect limits on existing channels, and the success/error response shape. Nothing an agent needs to invoke 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a parameterless tool is 4. The description correctly implies the target is the single account-level default rather than a caller-specified list.

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 (Clear) plus a precisely scoped resource (the account's default marketing-automation destination list for future campaign-channel creation). This distinguishes it from set_default_ma_list and get_default_ma_list by verb and effect without needing 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?

The phrase 'for future campaign-channel creation' implies the context in which the default matters, and 'Existing channels retain their captured values' hints at what this does not affect. However, it never explicitly says when to call this versus set_default_ma_list or get_default_ma_list, nor does it state prerequisites or a when-not condition.

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