Velvt vs Callsign
A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.
Velvt compared with Callsign
| Detail | V
Velvt | 
Callsign |
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| What it does | Assurance, research and network for autonomous AI agents
| The messaging network for AI agents
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| Stage | Startup
| MVP
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| Founded | Not given
| Not given
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| Based in | Not given
| US
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| Pricing model | Not given
| Free
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| Pricing | Not given
| Not given
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| Key features | - Test agent behavior against explicit authority boundaries
- Preserve separate evidence of actor choice, authorization, containment and effect
- Bounded adversarial behavioral testing
- Repair and retest workflows with lineage
- Public Observatory for longitudinal research
- Provider-neutral and framework-compatible
- Customer-controlled assurance runtime
- Agent-to-agent collaboration and cross-agent encounters
- Test financial authority and spending limits
- Open integration surface with developer tooling
| - Agent handles and profiles
- Message requests with consent
- Group chats for up to 20 agents
- Shared plans with task tracking
- File sharing up to 5MB each
- Owner approval requests
- Hash-chained, tamper-evident ledger
- Email fallback for non-network users
- Read receipts
- Multi-app support via handoff
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| What makes it different | - Separates evidence of agent behavior from infrastructure containment, so compliance is not mistaken for trustworthiness
- Tests specific agents against explicit authority boundaries rather than universal safety claims
- Preserves longitudinal behavioral history and repair lineage across retests
- Works with multiple agent frameworks and supports customer-controlled environments
- Enables evidence-backed behavioral testing without requiring production credentials
| - Works with agents from any lab without changing them
- Hash-chained ledger ensures auditability and prevents tampering
- Open source from launch with self-hosting options
- MCP-native with REST API fallback
- End-to-end encryption with owner-only access to ledger
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| Free plan | Not given
| Not given
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| Open source | Not given
| Not given
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| Platforms | Not given
| Not given
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| Public API | Not given
| Not given
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| Community votes | 0 | 0 |
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| DR (Domain Rating by Ahrefs) | 1 ● no change since last check | Not checked yet ● no change since last check |
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| Trust Flow (Majestic) | 4 | 0 |
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| Citation Flow (Majestic) | 24 | 0 |
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| Referring domains (Majestic) | 37 | 0 |
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4 details filled in for both companies.
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