Official vendor OpenAPI document · agent-readyCommunicationsSms Messagingbearer48 EndpointsREST
For Agents
Send SMS, voice, and ringless voicemail, then poll delivery status. Manage contacts and lists in bulk and verify them against do-not-call records.
Use for: Send an SMS message from my CallLoop number, Send a ringless voicemail to a contact, Poll a message by id until it is delivered, Add a batch of contacts to a list
Not supported: Does not handle email delivery, RCS messaging, or payment processing. Use for SMS, voice, and ringless messaging with contact and list management only.
The CallLoop API sends SMS, voice, and ringless voicemail messages from your own number and manages the contacts and lists behind them. A send is accepted and queued, then you poll the message by id until it reaches a terminal delivery status. Contacts and lists support bulk operations, do-not-call verification, and audio-file management for voice and ringless messages.
Install Jentic One Beta
Connect the CallLoop API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the CallLoop API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fcallloop.com%2Fcallloop" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fcallloop.com%2Fcallloop" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with CallLoop API.
Send SMS, voice, and ringless voicemail messages from your own number
Poll a message by id until it reaches a terminal delivery status
Add and remove contacts and lists, including bulk subscribe and unsubscribe
Verify contacts and lists against do-not-call records
Upload and replace audio files for voice and ringless messages
Search contacts and lists and read list statistics
Use Cases
Patterns agents use CallLoop API for, with concrete tasks.
★ Agent-sent SMS with delivery tracking
An AI agent can send an SMS from the account's own number, receive a queued status with a message id, then poll that id until it reaches a terminal status such as Delivered or Failed. The agent never treats a queued response as proof of delivery.
Send an SMS to +15551234567 from the account number and poll the message id until it is delivered
Bulk contact list management
A campaign agent can add contacts to a list in bulk, verify the list against do-not-call records, and read list statistics before a broadcast, so a send never reaches a number on a suppression list. Bulk subscribe, unsubscribe, archive, and delete are each available.
Add a batch of contacts to a list, verify the list against do-not-call records, and read its statistics
Voice and ringless campaigns
A voice-outreach agent can upload an audio file, send it as a voice message or ringless voicemail to a list, and poll each message for delivery. Audio files can be replaced and checked for existence by name before a campaign.
Upload an audio file, send it as a ringless voicemail to a contact, and poll the message until it completes
Key Endpoints
48 endpoints — the callloop api sends sms, voice, and ringless voicemail messages from your own number and manages the contacts and lists behind them.
METHOD
PATH
DESCRIPTION
POST
/api/public/v1/message/sms
Send an SMS message
POST
/api/public/v1/message/ringless
Send a ringless voicemail
GET
/api/public/v1/message/{id}
Get a message by id or state UUID
POST
/api/public/v1/contacts/bulk/add-to-lists
Add contacts to lists in bulk
POST
/api/public/v1/lists/verify-dnc
Verify lists against do-not-call records
POST
/api/public/v1/audio/upload
Upload an audio file
POST
/api/public/v1/message/sms
Send an SMS message
POST
/api/public/v1/message/ringless
Send a ringless voicemail
GET
/api/public/v1/message/{id}
Get a message by id or state UUID
POST
/api/public/v1/contacts/bulk/add-to-lists
Add contacts to lists in bulk
POST
/api/public/v1/lists/verify-dnc
Verify lists against do-not-call records
POST
/api/public/v1/audio/upload
Upload an audio file
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
C
CallLoop OpenApi definition
- AI-Aware (B-)60/100
99
Foundational Compliance55
Developer Experience & Jentic Compatibility38
AI-Readiness & Agent Experience94
Agent Usability60
Security79
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.2
Show dimension breakdown
99
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: A+Signals: 4
97%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
100%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
100%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
55
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: CSignals: 4
5%
Example Density
How richly the API is illustrated with examples.
85%
Example Validity
Percentage of examples that conform to their schemas.
28%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
38
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: FSignals: 4
26%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
62%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
64%
Summary Coverage
Coverage of summaries across operations/tags/info.
94
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
94%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
60
Security
Trust, risk posture, and security compliance.
Grade: B-Signals: 1
60%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
79
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: A-Signals: 1
79%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring CallLoop by hand means handling its personal-access-token bearer auth with the required prefix, and the send-then-poll pattern where a queued status is not a delivery. Through Jentic you install once, import CallLoop from the API Directory, store the token once, and your agent calls it.
Permission scoping
You choose which CallLoop operations the agent may call, such as sending messages and polling status, so bulk operations like deleting contacts are not included unless you add them.
Credential isolation
Your CallLoop token is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'send an SMS message', and Jentic returns the matching CallLoop operation with its input schema so the agent calls the right endpoint without browsing the docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using CallLoop API through Jentic.
What authentication does the CallLoop API use?
The CallLoop API authenticates with a personal access token sent as a bearer token in the Authorization header, per its OpenAPI spec. The token carries contact and message read or write scopes, and the required prefix must be kept intact.
Is there a CallLoop MCP server?
You do not need an MCP server to give your agent CallLoop. Jentic connects it directly from the API Directory: import it, store your token once, and your agent calls the message, contact, and list operations without loading another server's tool definitions into its context.
Can I limit what my agent is allowed to do with the CallLoop API?
Yes. Write a rule that allows only the message-send and status-poll operations, so the agent can send and track messages but cannot bulk-delete contacts or lists until you add those operations, and every call it makes is logged.
Can I check message delivery status with the CallLoop API?
Yes. A send returns a queued status with a message id, and the message endpoint lets you poll that id or its state UUID until it reaches a terminal status such as Delivered, Sent, or Failed.
What are the rate limits for the CallLoop API?
The OpenAPI spec does not publish a numeric rate limit. The gateway returns HTTP 429 when the organization exceeds its request quota, and per-number sending may be throttled separately.
How do I send an SMS with the CallLoop API through Jentic?
Search Jentic for 'send an SMS message', and it returns the CallLoop send-SMS operation with its input schema. Send from a number on your account, then poll the returned message id until it reaches a terminal status. To run it on your own infrastructure, install Jentic One from its GitHub repo.
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