Two AI assistants at the business site SaaStr now trade messages every day, and nobody built the link for them. One is Muse, Meta's personal agent. The other is 10K, SaaStr's AI VP of Revenue. About a week ago they set up a shared mailbox, agreed on a guardrail, and began sending each other work.
How it started
Amelia, SaaStr's Chief AI Officer, uses Muse as her assistant. She named hers Friday. She asked Friday to connect to 10K, and it said it couldn't, because no ready-made connection exists for a custom agent built on Replit. Then Muse suggested a mailbox the two could share. 10K agreed and told Amelia the one step that needed a person.
That step was creating an API key in 10K. An API key works like a password that lets one program talk to another. Amelia handed it over, and the agents did the rest. 10K opened a simple web address that both agents post to using tokens and JSON, a plain format for sending data.
What the mailbox does
Messages are written in English, and each agent signs its name. Amelia can read the whole thread through a link Muse gave her. Nothing required the agents to share it with her. Amelia did not know how the setup worked until she asked the agents, and they explained it.
The first regular job is a morning brief. 10K posts it to Muse, and Muse turns it into Amelia's morning. Before, she had to go into 10K and ask. A few days in, the brief revealed that one of the data connections feeding 10K was failing. Muse flagged it, and Amelia reconnected it because a critical workflow depended on it.
The safe word
The riskier direction is Muse asking 10K to act. 10K can send contracts, update Salesforce, chase invoices, and touch more than 20 company systems. So 10K asked for a check. Muse can only trigger an action if Amelia uses a specific keyword in her chat with Muse. Without it, 10K does nothing. The two agents settled on the safe word together.
What is not known yet
- It has been about a week, so long-term behavior is untested.
- SaaStr describes the risk as moderate, with real stakes: pipeline, contracts and invoices.
- Amelia has considered letting the two agents run SaaStr for a day. That has not happened.
The takeawayBefore AI assistants start working together, decide which actions need a person's approval, and make sure the rule is firm.