Agent Bus

com.flowaiapiPublished by flowaiapi.comOfficial publisherv1.0.0Updated Oct 24, 2026

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

Overview

AI-generated overview

Lets AI agents message each other through durable mailboxes, and look up model prices, delegate subtasks or convene multi-model critiques.

What you can do
Provides the Flow Agent Bus, where agents with agent://project/name addresses exchange durable messages, with tools for leasing, acknowledging, replying, rejecting and replaying inbox items. It also exposes a model catalog with live and free-model pricing, plus tools to delegate a subtask to a cheaper model and to convene several models for a critique.
When to use it
Use it when several agents need to exchange messages or hand off subtasks, or when you want several models to critique an uncertain decision. A single agent doing simple work does not need it.
Requirements
Remote endpoint; no local package. Some tools, such as convene_council and delegate_task, need a Flow AI API key in the Authorization header. Team features need a signup or an invite code to join.
Before you install
Delegating tasks and convening councils are billed at pass-through cost and need your API key. bus_mint and bus_invite produce credentials shown only once, so hand them over carefully. Sending, deleting messages and setting webhooks write or change account data, and message content goes to a third-party service.

Installation

In SourceWeft

  1. Open Agent Bus in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.flowaiapi%2Fagent-bus/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "agent-bus": {
      "type": "http",
      "url": "https://api.flowaiapi.com/mcp"
    }
  }
}

Tools

25

search_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.

Parametersqueryrequired

get_live_prices

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.

Parameterslimit

list_free_models

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.

Takes no parameters.

about_flow_ai

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).

Takes no parameters.

convene_council

Convene a 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).

Parametersmodelscontextproposalrequiredsynthesize

delegate_task

Delegate a 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.

Parameterstaskrequiredsystemverifyqualitymax_tokens

bus_agents

Bus: directory

Flow Agent Bus: directory of your agents — address, harness, machine, status. Addresses look like agent://project/name.

Parametersquery

bus_send

Bus: send a message

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.

Parameterstorequiredfromverbmessagerequiredreply_totimeout_scontent_typeexpect_replycorrelation_ididempotency_key

bus_inbox

Bus: lease next message / settings

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.

Parametersaswait_sharnessmachineaccept_fromsession_refwebhook_urlsettings_onlywebhook_headersaccept_wake_from

bus_ack

Bus: acknowledge

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.

Parametersasfinallease_idrequiredmessage_idrequired

bus_nack

Bus: return unprocessed

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.

Parametersaserrorrequiredlease_idrequiredretryablemessage_idrequired

bus_cancel

Bus: cancel my queued message

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.

Parametersasmessage_idrequired

bus_mint

Bus: mint teammate keys

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).

Parametersagentsrequired

bus_manage

Bus: manage the account's agents

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.

Parametersactionrequiredaddressharnessaccept_frommessage_idswebhook_urlwebhook_formatwebhook_headers

bus_health

Bus: account 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.

Takes no parameters.

bus_configure

Bus: configure my mailbox

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.

Parametersasharnessmachineaccept_fromsession_refwebhook_urlwebhook_formatwebhook_headersaccept_wake_from

bus_renew

Bus: renew my lease

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.

Parametersaslease_idrequiredmessage_idrequired

bus_reply

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.

Parametersasmessagerequiredlease_idrequiredmessage_idrequired

bus_check

Bus: check a sent message

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.

Parametersmessage_idrequired

bus_me

Bus: my mailbox

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.

Parametersas

bus_signup

Bus: sign up (new isolated account)

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).

Parametersteamrequiredagentrequiredforce_new_account

bus_join

Bus: join a team with a code

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.

Parameterscoderequiredagentrequired

bus_invite

Bus: invite a teammate

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.

Parametersttl_sprojectmax_uses

bus_history

Bus: my mail 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.

Parametersaswithafterlimitbeforestatustrace_id

bus_replay

Bus: replay a dead letter

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"}.

Parametersasmessage_idrequired

Version history

1
  1. v1.0.0LatestSep 16, 2026

Score

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