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

Annotations declare readOnlyHint, idempotentHint, etc., but the description adds valuable behavioral context: the different suppression reasons and their effects ('nothing goes to them' vs 'unsubscribed but individual email still reaches them'), the meaning of the 'scope' field, and the crucial note that no tool can remove an address (manual action required). This goes well beyond annotation coverage.

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 description is a single, dense paragraph that front-loads the core purpose and then adds necessary nuances. It's not overlong but could be slightly tightened. Every sentence adds value: reasons, scope field, and removal caveat.

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?

The tool has no output schema, so the description must explain return content. It does explain the reasons and the scope field, which is likely part of the return. However, it doesn't describe pagination behavior (limit/cursor) or the exact return structure. Still, for a read-only list tool, this is fairly complete.

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 33% (only email has a description). The description doesn't detail parameters, but it explains the 'scope' field semantically, which is not a parameter but a return field. For the parameters, there's no added meaning beyond the schema's 'email' description. However, the baseline for 33% coverage would be lower; the description compensates somewhat with domain context. Given the schema does document email and the other two are standard pagination, a 4 is fair.

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?

Clearly states it lists suppressed addresses with their reasons. It distinguishes itself from siblings like add_subscriber or erase_subscriber by describing the suppression domain, but doesn't explicitly contrast with add_suppression or mention that no sibling provides the opposite removal action. Still, the verb+resource is clear.

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?

Describes what the tool returns and notes that removal is a manual action in the Mailcheer workspace, not via any tool. This implies appropriate usage (read-only list) and warns against expecting a removal tool. However, it doesn't state when an agent should use this versus list_subscribers or other list tools.

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