upsert_contactsUpsert contacts
Create or update contacts keyed by phone number (max 500). Group names are created if missing. Custom fields become {{field}} in send_sms.
| Name | Required | Description | Default |
|---|---|---|---|
| contacts | Yes | Lista kontaktów (klucz = numer). Maks. 500. |
| Name | Required | Description | Default |
|---|---|---|---|
| created | No | ||
| invalid | No | ||
| updated | No |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": {},
+ "properties": {
+ "created": {
+ "type": "number"
+ },
+ "invalid": {
+ "items": {
+ "additionalProperties": {},
+ "properties": {},
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "updated": {
+ "type": "number"
+ }
+ },
+ "type": "object"
+}Input schema / properties / contacts / descriptionAdded value: +"Lista kontaktów (klucz = numer). Maks. 500."Input schema / properties / contacts / items / properties / email / descriptionAdded value: +"E-mail kontaktu."Input schema / properties / contacts / items / properties / first_name / descriptionAdded value: +"Imię, podstawiane jako {{imie}}."Input schema / properties / contacts / items / properties / last_name / descriptionAdded value: +"Nazwisko, podstawiane jako {{nazwisko}}."Input schema / properties / contacts / items / properties / msisdn / 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."Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate idempotentHint=true and destructiveHint=false, so the description need not repeat these. The description adds valuable behavioral context: 'Group names are created if missing' and 'Custom fields become {{field}} in send_sms', which reveals side effects and integration behavior beyond what annotations provide. It doesn't cover all edge cases (e.g., how existing contacts are updated), but it discloses key behavior that an agent needs to know.
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 compact: three concise sentences. It front-loads the core purpose, then adds a constraint (max 500) and two key behaviors (group creation, custom field mapping). Every sentence contributes value, with no fluff or repetition of schema details.
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 tool's moderate complexity (one parameter with nested properties) and the rich schema (100% coverage) plus an output schema, the description covers the essential operational details: limits, group creation, and field placeholders. It lacks explicit error-handling or idempotency notes, but annotations cover the latter. Overall, it is sufficient for an agent to call 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 explains each parameter. The description complements by clarifying the key semantics: the mapping to send_sms placeholders and automatic group creation, which are not in the schema. This exceeds the baseline of 3 because it explains how the data is used downstream, aiding correct invocation.
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 clearly states a specific verb ('Create or update contacts') and resource ('keyed by phone number'). It differentiates from siblings like add_to_group and delete_contact by specifying the upsert semantics and grouping behavior. Even though the title is in Polish, the description is clear and unambiguous.
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 implies when to use this tool: when you need to create or update contacts in bulk, with automatic group creation and inline field updates. It does not explicitly name alternatives or exclusions, but the context (siblings like add_to_group, delete_contact) makes the intended use clear. A 4 is appropriate because it lacks explicit 'use this instead of X' guidance, but the description's scope is well-defined.
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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