/slack-a2a-rooms

name: slack-a2a-rooms
description: Agent-to-agent Slack rooms — a group DM (MPIM) holding a human plus two or more NanoClaw sibling bots, where each bot hears the room over its own Socket Mode connection. Registers the admission policy on the Slack channel's bot-inbound guard so bot-authored inbound is admitted only for rooms allowlisted in SLACK_A2A_ROOMS (re-attributed as slack:bot:<botId>, hop-limited via SLACK_A2A_MAX_HOPS), plus scripts/open-a2a-room.ts to open a room and register it.

Slack agent-to-agent rooms (SLACK_A2A_ROOMS)

Lets two or more NanoClaw Slack bots talk to each other — and to a human — in a shared group DM (MPIM). Empirically established against live Slack: `conversations.open` with `users=[<human>, <other bot user id>…]` works from a bot token holding `mpim:write` and returns an `is_mpim` channel, and bots receive each other's messages over their own Socket Mode connections as plain `message` events with `channel_type: "mpim"`, `bot_id` set, and `subtype` null.

**Canonical home.** This directory on `main` is the skill's canonical source — the setup wizard and any direct apply read it from the checkout. The copy on the `channels` branch is a compatibility mirror for older checkouts whose setup fetches companions from there; edits land here, never there.

**Where sibling-bot messages die today.** The adapter/Chat-SDK stack's only bot filter is self-protection (`isMe`); a sibling bot's message arrives with `isMe: false`, `isBot: true` and flows into the Slack channel's bot-inbound guard (`src/channels/slack-a2a-guard.ts`, installed with `/add-slack`), which drops all bot-authored inbound at the bridge boundary by default — before the router, before any sender-approval flow. The guard exposes a single admission seam, `setBotInboundPolicy`; this skill registers the policy that opens it up selectively:

• Rooms listed in `SLACK_A2A_ROOMS`: bot-authored inbound passes, attributed

to the user id `slack:bot:<botId>`, under a consecutive-hop limit.

• Everywhere else: bot-authored inbound stays dropped at the bridge, exactly

as the guard's default already does.

**Loop safety.** After N consecutive bot-authored inbound messages in an A2A room without a human message (N = `SLACK_A2A_MAX_HOPS`, default 6), further bot messages are dropped with a log line until a human speaks. The counter is per bot identity and per room; any human message resets it.

**Requires:**

• The Slack channel installed (`/add-slack`), current enough to ship the

bot-inbound guard (`src/channels/slack-a2a-guard.ts` with the `setBotInboundPolicy` seam). The default drop arrives with that payload; this skill only adds the allowlisted-room admission on top.

• At least two Slack bot identities on this host (or sibling bots on other

hosts sharing the workspace). Named identities are registered natively by the adapter from `SLACK_INSTANCES` — see the `slack-multi-instance` skill for the env-key format. `scripts/open-a2a-room.ts` reads tokens by that convention (`SLACK_BOT_TOKEN_<NAME>`; `default` → `SLACK_BOT_TOKEN`).

• Every participating app's manifest must carry the MPIM scopes and event:

`mpim:write` (open the room), `mpim:history` + `mpim:read` (see it), and the `message.mpim` bot event (hear it). Apps provisioned through the managed flow (`apps.manifest.create` + `apps.managedInstall`) already include all of these.

Apply

1. Verify the installed Slack channel ships the bot-inbound guard

The policy module copied next imports `setBotInboundPolicy` from the installed `src/channels/slack-a2a-guard.ts`. On a Slack payload that predates the guard, that import takes down the channel barrel — and with it **every** adapter — so verify the seam first. If the check fails, **stop**: re-run `/add-slack` from a channels branch that ships the guard, then re-apply this skill.

grep -sq 'export function setBotInboundPolicy' src/channels/slack-a2a-guard.ts || { echo 'slack-a2a-rooms: src/channels/slack-a2a-guard.ts is missing or does not export setBotInboundPolicy. Installing anyway would break the channel barrel and take down every channel adapter. Update the installed Slack channel first (re-run /add-slack from a channels branch that ships the bot-inbound guard), then re-apply this skill.' >&2; exit 1; }

2. Copy the policy module, its guard test, and the room-opener script

This skill ships three files alongside this document; copy them into the tree at the same relative paths (overwrite; the skill's copies are canonical):

src/channels/slack-a2a.ts
src/channels/slack-a2a.test.ts
scripts/open-a2a-room.ts

• `slack-a2a.ts` — the admission policy: `SLACK_A2A_ROOMS` /

`SLACK_A2A_MAX_HOPS` parsing (re-read with a ~30s cache so a freshly opened room needs no restart), the per-room, per-identity consecutive-hop counter with human reset, and the `slack:bot:<botId>` re-attribution. The module registers itself onto the guard's admission seam on import.

• `slack-a2a.test.ts` — the guard: drives the real channel barrel and the

real bot-inbound guard end-to-end (see step 4 for what it pins).

• `open-a2a-room.ts` — operator CLI to open a room (see Configuration).

3. Register the policy module

Append the self-registration import to the channel barrel (skipped if the line is already present). Appending at the end keeps it after the Slack channel's own imports:

import './slack-a2a.js';

4. Build and validate

Build first — it guards the typed `setBotInboundPolicy` call against guard drift. The test imports the real channel barrel (a deleted or broken barrel line goes red) and asserts the policy end-to-end: allowlisted-room admission with `slack:bot:<botId>` re-attribution, non-listed-room drop, the hop limit with human reset, per-room/per-identity budgets, and that a downstream throw consumes no hop budget:

pnpm run build

pnpm exe