add_suppressionAdd an address to the suppression list.
| Name | Required | Description | Default |
|---|---|---|---|
| Yes | Address to stop sending to | ||
| reason | No | Optional note on why, e.g. "asked to stop" |
| Name | Required | Description | Default |
|---|---|---|---|
| suppression | Yes |
Changes observed during successful MCP inspections.
Input schema / properties / email / descriptionAdded value: +"Address to stop sending to"Input schema / properties / reason / descriptionAdded value: +"Optional note on why, e.g. \"asked to stop\""Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "suppression": {
+ "properties": {
+ "created_at": {
+ "description": "ISO 8601",
+ "type": "string"
+ },
+ "email": {
+ "type": "string"
+ },
+ "id": {
+ "description": "Suppression id",
+ "type": "string"
+ },
+ "reason": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "source": {
+ "type": "string"
+ },
+ "updated_at": {
+ "description": "ISO 8601",
+ "type": "string"
+ }
+ },
+ "required": [
+ "id",
+ "email"
+ ],
+ "type": "object"
+ }
+ },
+ "required": [
+ "suppression"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=false, covering the safety profile. The description adds no extra behavioral context such as permission requirements, effect on future sends, or rate limits. It does not contradict the annotations.
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?
A single front-loaded sentence with no wasted words. It is terse but efficient, though arguably under-specified given the tool's side effects.
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 an output schema and full parameter descriptions already present, the description need not explain return values. However, it omits usage context and the operational meaning of suppression, leaving minor gaps for a mutation tool.
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 description coverage is 100%, so the baseline is 3. The description adds no syntax or format details beyond what the schema already provides for email and reason.
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 states a specific verb and resource: 'Add an address to the suppression list.' It is clearly an additive operation, distinguishable from list_suppressions and remove_suppression, but it does not explicitly name or contrast those siblings.
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?
No when-to-use, when-not-to-use, or alternative-tool guidance is provided. The agent must infer that this is for suppressing an address and that remove_suppression handles the reverse operation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.