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

Annotations only declare destructiveHint=true; the description adds real value beyond that: it labels the operation WRITE, clarifies it is list-scoped rather than account-wide, and discloses that the change is reversible by re-adding the subscriber. It does not cover auth requirements or rate limits, which keeps it below 5.

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?

Three tightly packed segments with the operation type front-loaded as 'WRITE:'. Every clause earns its place: scope, reversal path, and endpoint mapping.

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 destructive two-parameter write with no output schema, the description covers scope, reversibility, and endpoint, which is enough to invoke correctly. It says nothing about the response or error behavior, a minor gap given no output schema exists to cover it.

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 parameters are fully documented in-schema, so the baseline is 3. The endpoint template echoes {MailingListID} but adds no new semantic detail about the parameters beyond what the schema already states.

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 and resource ('unsubscribe one email address from one mailing list') and immediately bounds the scope with '(not account-wide)'. That scope qualifier lets an agent distinguish this from account-level or bulk unsubscribe operations without opening a 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?

Gives clear context: use when removing a single address from a single list, and it names the reversal path (moosend_add_subscriber). It does not state explicit when-not conditions or alternatives for removing on an account-wide basis, so it falls short of the top score.

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