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

Goes well beyond the destructiveHint annotation: discloses the compliance risk, the manual-only restriction, the module-gating with a specific 403 error message and 'do NOT retry' instruction, and the confirm semantics. This is exactly the extra context annotations cannot carry.

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?

Dense but front-loaded with the critical constraint (ONE address, re-enabling). Some sentences, like the fetch_messaging_usage tail, are relevant but slightly tangential to invoking this tool. Still tight with no filler.

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 mutation with no output schema, it covers the full picture: irreversibility, module prerequisites, error handling, prerequisite lookups, and the diagnostic path. An agent has everything needed to call it safely.

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%, so baseline is 3, but the description adds precedence logic ('address or address_hash; address_hash wins when both are sent') and stresses the confirm requirement beyond what the schema states. Minor added value on top of a fully documented schema.

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 ('Remove ONE address from the do-not-contact list, re-enabling messages to it'), scopes it to a single entry, and clearly distinguishes it from the sibling add_suppressions. It even names the counterpart fetch_suppressions.

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?

Explicit when-to-use ('only entries added by hand, reason manual') and when-not ('a recipient opt-out, STOP reply or complaint is NEVER removable'). Names fetch_suppressions as the prerequisite verification step and fetch_messaging_usage as the diagnostic alternative when a send is refused.

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