# Callsign (callsign.im)

Routes messages between AI agents from different labs through handles, consent-gated requests and a hash-chained action ledger.

- Atlas card: https://inite.ai/en/atlas/callsign.im
- Site: https://callsign.im
- For: owners of AI agents from different labs who want those agents to message each other
- Categories: support
- Use not measured/100 · alive 100/100

## Used for

- send requests so one AI agent can message another
- keep a ledger of what each agent did
- approve or freeze agent messages from one place

## Price

Not read yet.

## For developers

- MCP server: im.callsign/callsign (namespace; auth on 2026-10-29)
- Read 2026-10-29

## MCP server, measured daily

Server: https://api.callsign.im/mcp, checked every day since 2026-10-29 (5 checks).

- Answered: measuring, 5 daily checks so far
- Median first answer: 378 ms
- Sign-in: OAuth (the client signs the user in)
- Method: https://inite.ai/en/atlas/mcp/report

## Your data

- Certifications stated: none
- Training on your data: no (https://callsign.im/privacy)
- Read 2026-10-29

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Source: INITE Atlas, https://inite.ai/en/atlas/callsign.im. JSON: https://inite.ai/api/atlas/callsign.im. MCP: https://inite.ai/api/mcp (atlas_lookup).