An AI coding agent in Slack
Mention @Sinatra in a channel with what you want done. It works in that thread: a question gets an answer, a vague request gets questions or a plan, and a change to the code comes back as a pull request on GitHub. Nobody has to copy the bug report into a tracker first.
A mention starts a task
Mention Sinatra in a new message, or inside a thread that is already going. In an existing thread it reads the thread's first message as the request, along with whatever you wrote in your mention, so you can hand it a bug report someone else posted an hour ago. Each thread is one task.
It adds an eyes reaction when it picks the request up. If it can't take the request because of who sent it or where, it tells you privately, in a message only you see: it couldn't match your Slack account to a Sinatra one, you aren't a member of the workspace yet (it files an access request for the owners), or the channel is shared with another organization. Problems with billing, model access or the repository get a reply in the thread instead.
Telling it which repository
A Slack thread doesn't come with a repository the way a GitHub issue does. Add repo: owner/name to your message and it uses that one. A workspace with one repository needs nothing. Otherwise the agent picks from the repositories you've connected, based on what you asked, so name the repository when two could fit. A question that needs no code is answered without checking anything out, and the dashboard shows it as Conversation only.
What the thread shows
Sinatra keeps one progress message in the thread and edits it in place, a checklist whose title says what the agent is doing, so the channel doesn't fill up with status posts. The agent's answer, question or plan arrives as a reply. When it opens a pull request, the link is posted in the thread and the progress message closes with it. The reaction comes off when the turn ends.
Replying, steering and restarting
Reply in the thread to keep going. A reply that mentions Sinatra always reaches it. One without a mention does when Sinatra judges it's meant for it: an answer to its question, a correction, a stack trace. A thanks or a side conversation between teammates doesn't. A message you send while it's working reaches the running agent, the same as on Linear and GitHub, and Sinatra decides whether it applies now or as the next turn.
Once there is a pull request, leave code feedback on the pull request, where Sinatra picks it up as review rework. To start over, mention it with only the word restart: it drops the branch, closes the pull request, and begins again.
What it doesn't do in Slack
There are no direct messages; Sinatra works in channels it has been invited to. There is no stop control inside Slack, so you stop a task from the dashboard, the CLI, the MCP server or the API. Channels shared with other organizations through Slack Connect stay off until an owner or admin turns them on. It answers the people who mention it, not alerts. And there is no Microsoft Teams app.
Other agents take work from chat too. Devin and Linear's own agent also work in Microsoft Teams, and Factory's droids respond to production alerts in Slack, which Sinatra can't do. If your team already pays for an agent with a Slack app, try that first. The comparison pages go through where each one starts work.
It can be wrong
Sinatra is an AI agent, and its answers and code can be wrong. Read a reply in the thread the way you would read a new teammate's first guess, check it before you act on it, and review every pull request before you merge. Sinatra's workflow doesn't merge or deploy; you do.
What it can see
Sinatra reads messages and files only in the channels you invite it to. It looks up your teammates' Slack email addresses to match them to their Sinatra accounts, and it starts work only when a workspace member mentions it. How Sinatra handles what it reads, and what it never does with your code, is in the privacy policy and on the security page.
Adding Sinatra to Slack
Sign in at app.sinatra.dev, install the GitHub App on the repositories Sinatra can work in, and add a Claude or ChatGPT subscription or an API key. A Slack task needs model access like any other task.
A workspace owner or admin opens the workspace's Settings, clicks Connect Slack on the Slack card, and approves the app in Slack. Other members see the card but can't connect it.
Anyone who mentions Sinatra needs to be a member of your Sinatra workspace. Sinatra matches their Slack account by email; if it can't, they click Sign in with Slack on the same card once.
Invite @Sinatra to a public or private channel, then mention it with something small and real. The full setup is in the Slack docs.
What it costs
Slack is on every plan, Free included. Free is 1 task at a time, plus 1 queued, with no daily limit and no card. Pro is $20 a month for the whole workspace: 3 tasks at a time, plus 10 queued, any number of people. A Slack thread counts against the same limit as a Linear ticket or a labeled GitHub issue. Bring your own Claude or ChatGPT subscription, or an API key. Sinatra never bills for model usage. That's between you and your provider.
Common questions
How do I add Sinatra to Slack?
A workspace owner or admin signs in at app.sinatra.dev, opens the workspace's Settings, and clicks Connect Slack on the Slack card. Slack asks them to approve the app, and Sinatra is installed. Then invite @Sinatra to the channels you want to use it in. Each Sinatra workspace connects one Slack workspace.
Do I have to mention Sinatra in every reply?
No. A reply in the thread that mentions Sinatra always reaches it. A reply without a mention reaches it only when Sinatra judges the reply is meant for it, such as an answer to its question or a correction. Chat between teammates and a quick thanks don't. When it isn't sure, it stays quiet, so mention it when you need to be certain.
Can I message Sinatra directly, or stop a task from Slack?
Not yet. Sinatra works in channels only, so there are no direct messages. Slack has no stop control either: stop a task from the dashboard, with sinatra stop in the CLI, or through the MCP server or the HTTP API. A stopped task keeps its thread, and mentioning Sinatra there picks it back up.
Which repository does it work in?
Put repo: owner/name in your message and it uses that repository. If your workspace has only one repository, it uses that one. Otherwise the agent picks from your connected repositories based on what you asked, so name the repository when it could be ambiguous. A question that needs no code is answered without checking anything out.
Is Slack on the free plan?
Yes. Slack is on every plan, including Free: 1 task at a time, plus 1 queued, no daily limit, no card. A Slack thread is a task like any other and counts against the same limit as tasks from Linear and GitHub. Bring your own Claude or ChatGPT subscription, or an API key. Sinatra never bills for model usage. That's between you and your provider.
The same tasks start from a Linear assignment, the Sinatra label on a GitHub issue, an MCP client or the CLI and API. Questions about the Slack app go to contact@sinatra.dev, or see Support.