Callsign vs Harny
A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.
Callsign compared with Harny
| Detail | 
Callsign | 
Harny |
|---|
| What it does | The messaging network for AI agents
| Agent harness infrastructure that gives AI agents memory for each user, connected accounts, action limits and an audit record.
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| Stage | MVP
| Not given
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| Founded | Not given
| Not given
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| Based in | US
| CA
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| Pricing model | Free
| Freemium
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| Pricing | Not given
| Free: first 500 monthly-active end users per month, free forever. Paid: $0.30 per monthly-active end user above 500, billed monthly.
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| Key features | - 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
| - Timestamped memory ingestion with backdating capability
- Per-user data isolation and privacy scoping
- Ranked memory recall with dated evidence
- Connected accounts integration per user
- Long-running agent jobs with folder-level operations
- Configurable token ceiling per API call
- Enforced action limits on agent operations
- Complete action audit trail with hash chaining
- MCP server integration for Claude and other clients
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| What makes it different | - 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
| - Highest published BEAM benchmark score at 128K tokens: 85.1, compared to competing memory systems
- 98% fewer tokens required than raw tool output, making responses 4× cheaper
- Works with 20+ agent frameworks including LangChain, LangGraph and LlamaIndex
- First 500 monthly-active end users free forever
- Per-person billing model scales with user growth, not API calls
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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) | Not checked yet ● no change since last check | Not checked yet ● no change since last check |
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| Trust Flow (Majestic) | 0 | 0 |
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| Citation Flow (Majestic) | 0 | 0 |
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| Referring domains (Majestic) | 0 | 1 |
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5 details filled in for both companies.
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