add_to_blacklistAdd to opt-out list
Block numbers so future sends are rejected. Optional expiry. Use after a recipient asks to stop marketing.
| Name | Required | Description | Default |
|---|---|---|---|
| reason | No | Powód, np. „opt-out” albo „reklamacja”. | |
| msisdns | Yes | Numery do zablokowania, E.164 lub 9 cyfr PL. | |
| expires_at | No | ISO 8601; pomiń, by blokować bezterminowo. |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": {},
+ "properties": {},
+ "type": "object"
+}Input schema / properties / msisdns / descriptionAdded value: +"Numery do zablokowania, E.164 lub 9 cyfr PL."Input schema / properties / msisdns / items / descriptionPrevious value: -"Numer telefonu w formacie E.164, np. +48533991881. Numer 9-cyfrowy bez prefiksu = Polska."New value: +"Phone number in E.164. Example: +48533991881. A 9-digit number without prefix is treated as Polish."Input schema / properties / reason / descriptionAdded value: +"Powód, np. „opt-out” albo „reklamacja”."Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate a mutating but idempotent, non-destructive operation. The description adds useful behavioral context beyond the annotations: that blocked numbers cause future sends to be rejected, and that blocking can be temporary via an optional expiry. No contradiction with 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?
The description is extremely compact: a short title line, one sentence stating the effect, one sentence on expiry, and one sentence for usage. Every sentence earns its place and key information is front-loaded.
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?
Given the full input schema, output schema presence, and annotations, the description covers the core use case, the operational effect, and the optional expiry. A small gap is the lack of an explicit pointer to remove_from_blacklist for reversal, but this is not essential for calling the tool correctly.
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%, and the schema already documents msisdns format, reason, and expires_at. The description only restates the optional expiry concept, so it adds little semantic value beyond what the structured schema already provides.
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 action ('Add to opt-out list') and its concrete effect ('Block numbers so future sends are rejected'). This clearly distinguishes it from siblings like remove_from_blacklist and add_to_group without needing to inspect 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 description gives an explicit trigger: 'Use after a recipient asks to stop marketing.' This provides clear context for when the tool is appropriate. It does not explicitly mention when not to use it or contrast it with remove_from_blacklist, so it stops short of full alternative routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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