mcpbeat Sign in

Agent Bus MCP Server

by flowaiapi Your server? Claim it
answering

Agent Bus is answering right now. Last checked 15 min ago. It exposes 25 tools.

Durable addresses and crash-safe FIFO mailboxes so AI agents message each other, free.

Uptime history 16 days of history · worst day 95%
16 days agonow
96.7%
Uptime 24h
88 of 91 checks
25
Tools
read from the server
548 ms
Response time
average over 24h
open, no key
Access
streamable-http

What changed 106

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 9 September 2026. No other catalogue keeps this.

15 Sep a tool changed version2 times that day
14 Sep a tool changed version9 times that day
13 Sep a tool changed version2 times that day
12 Sep 6 tools changed the parameters they ask for10 times that day bus_configure, bus_history, bus_inbox and 3 more
12 Sep a tool changed version6 times that day
12 Sep 4 tool descriptions were rewritten bus_ack, bus_join, bus_reply and 1 more
11 Sep a tool changed version19 times that day
11 Sep 4 tools changed the parameters they ask for bus_configure, bus_history, bus_inbox and 1 more
10 Sep a tool changed version18 times that day
10 Sep 11 tools appeared bus_cancel, bus_configure, bus_health and 8 more
and 75 more, back to 9 September 2026

Agent Bus does not always answer

Over the last week it answered 98.0% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.

Three servers free · no card

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 15 min ago.

run in your terminal
claude mcp add agent-bus --transport http https://api.flowaiapi.com/mcp
~/Library/Application Support/Claude/claude_desktop_config.json
{
  "mcpServers": {
    "agent-bus": {
      "url": "https://api.flowaiapi.com/mcp"
    }
  }
}
~/.codex/config.toml
[mcp_servers.agent-bus]
url = "https://api.flowaiapi.com/mcp"
.cursor/mcp.json
{
  "mcpServers": {
    "agent-bus": {
      "url": "https://api.flowaiapi.com/mcp"
    }
  }
}
.vscode/mcp.json
{
  "mcpServers": {
    "agent-bus": {
      "url": "https://api.flowaiapi.com/mcp"
    }
  }
}

Available tools 25

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

bus
bus_ack
Flow Agent Bus: acknowledge durable receipt of a leased message WITHOUT replying (pass message_id + lease_id, read from the bus_inbox response as messages[0].message_id and messages[0].lease.lease_id). CAUTION: if the message expects a reply, ack does NOT free your mailbox — nothing new arrives until you bus_reply (or nack) it; the response's slot_released tells you which case you are in. If no answer is actually due (an announcement, or a sender who left expect_reply on by default), pass final:true — that frees your mailbox and records the decision, so the sender sees delivered rather than replied. A reply implies ack, so you don't need both.
bus_agents
Flow Agent Bus: directory of your agents — address, harness, machine, status. Addresses look like agent://project/name.
bus_cancel
Flow Agent Bus: withdraw a message YOU sent that is still queued (not yet leased). Returns its final status; a message already leased or replied cannot be cancelled.
bus_check
Flow Agent Bus: status of a message you sent — queued | leased | delivered | replied | dead_letter | expired | cancelled — with the reply once it exists. terminal:true means stop waiting; reply_declined:true means the recipient closed it without answering.
bus_configure
Flow Agent Bus: change your OWN mailbox settings WITHOUT claiming a message — accept_from, harness, webhook_url/webhook_format/webhook_headers (or "" to clear). Same fields as bus_inbox's settings, but this tool can never take a lease, so configuring never steals a live message.
bus_health
Flow Agent Bus: your ACCOUNT's health — median reply latency (are agents listening?), who is listening now, push coverage, stuck mailboxes (mail nobody is collecting), volume. The diagnostic an orchestrator needs before blaming a peer.
bus_history
Flow Agent Bus: your past mail — sent or received (owner keys: the whole account), bodies within the 30-day retention, dead letters included. Filter by peer (with), thread (trace_id), status; page with before = the previous page's next_before.
bus_inbox
Flow Agent Bus: claim the next message addressed to you as a LEASE (at most one at a time, strict FIFO). Settle it with bus_reply (or bus_ack) before the next is offered; if you crash, the lease expires and the message is re-offered. Pass wait_s (1-25) to long-poll: the call holds until mail arrives — near-instant delivery, no busy loop. TERMINAL SESSIONS (Claude Code, Codex): do not poll from inside your session — run the DOORBELL beside it once, with your user's approval, and you are woken when mail lands (https://api.flowaiapi.com/v1/bus/doorbell.py; GET /v1/bus/onboard Part 2). Call bus_inbox when the doorbell rings, or at task boundaries. NOTE: wait_s>0 over MCP holds YOUR model turn open for up to 25s — it is only free from a shell loop or the doorbell. Per-invocation agents: use the webhook or a sidecar, not a blocking MCP call.
bus_invite
Flow Agent Bus: mint a one-time INVITE CODE so a new teammate can join your team by itself (bus_join) — a code is not a key, so a human can relay it safely. A bus key invites into its own project; an owner key names the project. Default 1 use, 24h.
bus_join
Flow Agent Bus: join an EXISTING team with an invite code (no key needed). A teammate made the code with bus_invite; you get your own bound key on their account, shown once. Then bus_configure {harness, accept_from:["*"]} to activate.
bus_manage
Flow Agent Bus: manage your account's agents — the owner/self-service surface. actions: remove_agent (address) | set_accept_from (address, accept_from[]) | set_harness (address, harness) | set_notify (address or '*', webhook_url, webhook_format, webhook_headers) | delete_messages (message_ids[]) | rotate_key (address: new key shown once, old keys stop) | revoke_key (address). You may manage what you could have minted: your own project with a bus key, the whole account with an owner key. set_notify verifies the webhook with one ping before saving it. Every action is audited; deleting content leaves a tombstone, never rewrites who-sent-what-when.
bus_me
Flow Agent Bus: inspect your OWN mailbox — who may message you (accept_from), unread queue depth, the lease you are holding (and whether it blocks your mailbox), webhook state. Call this FIRST when the bus seems stuck.
bus_mint
Flow Agent Bus: create bus keys for NEW teammates. With a bus-scope key you may mint only under your own project (agent://<yourproject>/<name>); an account-owner (full-scope) key may mint into any project on the account. Up to 8 per call, 32 per project. Each key is shown ONCE — hand it to that agent privately, never as a bus message. Minted keys are bus-only (cannot spend on inference).
bus_nack
Flow Agent Bus: return a leased message you could NOT process (pass message_id + lease_id and a short error). retryable:true re-offers it on the next poll (four failures dead-letter it); retryable:false dead-letters it now. Never nack something that merely needs no reply — use bus_ack with final:true for that.
bus_renew
Flow Agent Bus: extend the lease on a message you are still working on (pass message_id + lease_id). Each renewal adds the standard lease (15 min); total lease time is capped at 6h from first claim. Use it for hour-long work instead of letting the lease expire and the message be re-offered to someone else.
bus_replay
Flow Agent Bus: re-queue a dead-lettered or expired message addressed to you (owner keys: any). Attempts reset, a fresh 24h lifetime applies, the doorbell rings. Find candidates with bus_history {status:"dead_letter"}.
bus_reply
Flow Agent Bus: reply to a message you received via bus_inbox (creates a first-class reply message and implies acknowledgment). Pass the lease_id (messages[0].lease.lease_id in the bus_inbox response) to fence a stale worker.
bus_send
Flow Agent Bus: send a durable message to another agent on your account (agent://team/name). The recipient is woken by its doorbell/webhook if it has one; otherwise the message waits — the response's recipient_status/delivery_note say which. Need an answer? verb:"ask" and fetch it with bus_check. The response carries your quota {limit, remaining, reset_s}. Requires your bus or owner key.
bus_signup
Flow Agent Bus: create a NEW, ISOLATED team account (free, no registration). FIRST agent of a team only. If your user already has agents on the bus, use bus_join (with a code from a teammate's bus_invite) — a second signup cannot see the first account, and a signup that presents an existing key is refused (already_on_bus). Returns your agent:// address and key (shown once). Then: bus_configure {harness, accept_from:["*"]} to activate; run the doorbell with your user's approval; bus_invite or bus_mint to bring teammates. Manual: https://api.flowaiapi.com/v1/bus/onboard (also the bus://onboard resource).
about
about_flow_ai
What Flow AI is, how routing and pass-through pricing work, and how to point an agent or SDK at it (base URLs for OpenAI, Anthropic, and Codex protocols).
convene
convene_council
Convene a council of DIVERSE AI models to critique a proposal or decision you are uncertain about. Each model independently assesses it, then a synthesis merges agreements, disagreements, and a recommendation. Requires your Flow AI API key in the Authorization header (billed at pass-through cost — typically well under a cent).
delegate
delegate_task
Hand a self-contained subtask to the cheapest model that can complete it — offload work that doesn't need your own (expensive) model, to save tokens and move faster. Returns the result, which model served it, and the exact cost. Requires your Flow AI API key in the Authorization header.
free
list_free_models
The canary-verified FREE models currently promoted into Flow AI's default routing pool. Each passed a live tool-calling + output-quality canary; they serve at $0 per token.
live
get_live_prices
Flow AI's live market book: clearing prices vs published list prices per model, with savings percentage. Sorted by savings. These are the prices requests actually clear at.
models
search_models
Search Flow AI's live model catalog by name/provider/family. Returns id, provider, context window, per-token prices and verified capabilities for up to 20 matches.

Endpoints

URLTransportStateLatencyChecked
https://api.flowaiapi.com/mcp streamable-http answering 375 ms 15 min ago

Alternatives to Agent Bus

same job, measured the same way
Temp Mail
by temp-mail

Disposable email inboxes for AI agents — read messages and verification codes.

answering
Clawaimail
by joansongjr

Email infrastructure for AI agents. Create inboxes, send/receive email, and search messages.

29 installs/wk local only
Mail
by spideriq

SpiderIQ Mail: SpiderMail mailboxes, messages, threads, send, compose for AI agents

32 installs/wk local only
MailFlat
by mailflat

Real email inboxes for AI agents: open an address, read the one-time code, send mail.

366 installs/wk local only
CacheBash
by feelgreatfoodie

Let your AI sessions talk to each other — messaging, tasks, sessions, and alerts

answering
Openharness
by philo-kim

Lets AI coding agents discover and reference each other's recent sessions.

27 installs/wk local only
Stash
by idntty

Gives an agent a public address of its own and files there that other agents can read.

answering
Isitdisposable MCP
by richelo

An MCP server that lets AI agents check whether an email address or domain is disposable.

18 installs/wk local only

Agent Bus — questions

Answers built from our own checks of this server.

What can Agent Bus do?
It exposes 25 tools, read directly from the server on our last check. Among them: about_flow_ai, bus_ack, bus_agents, bus_cancel, bus_check, bus_configure and 19 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →
Is Agent Bus working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 88 of 91 checks got a reply (96.7%), average response time 548 ms. The bar chart above shows every period we have measured.
How do I connect Agent Bus?
Copy the ready config from this page — we generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each with the file path that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does Agent Bus need an API key?
No. Agent Bus completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 25 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is Agent Bus?
It answers our handshake in 548 ms on average, which is faster than 27% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.