diff --git a/cli/proof/677-reresolve-proof.png b/cli/proof/677-reresolve-proof.png
new file mode 100644
index 0000000..2c6f219
Binary files /dev/null and b/cli/proof/677-reresolve-proof.png differ
diff --git a/cli/src/slack-reresolve.test.ts b/cli/src/slack-reresolve.test.ts
new file mode 100644
index 0000000..5396bcc
--- /dev/null
+++ b/cli/src/slack-reresolve.test.ts
@@ -0,0 +1,95 @@
+import { test, describe } from "node:test";
+import { strict as assert } from "node:assert";
+import { matchPendingChannels, PendingAgent } from "./slack/reresolve.js";
+import type { SlackChannelInfo } from "./slack/client.js";
+
+const chan = (name: string, id: string, isMember: boolean, isPrivate = false): SlackChannelInfo => ({
+  id,
+  name,
+  isMember,
+  isPrivate,
+});
+const p = (slug: string, channel: string): PendingAgent => ({ slug, channel });
+
+describe("matchPendingChannels (the #677 self-heal core)", () => {
+  test("public channel that exists but the bot is NOT a member stays pending", () => {
+    // The #677 trap: conversations.list returns a public channel the moment it
+    // exists, before the invite. Mirroring it then would post to a channel the
+    // bot can't write to. Must NOT resolve until is_member flips true.
+    const { resolved, stillPending } = matchPendingChannels(
+      [p("kanban-keeper", "#agent-kanban-keeper")],
+      [chan("agent-kanban-keeper", "C1", false)],
+    );
+    assert.equal(resolved.length, 0);
+    assert.deepEqual(
+      stillPending.map((a) => a.slug),
+      ["kanban-keeper"],
+    );
+  });
+
+  test("resolves — with the channel id — once the bot becomes a member", () => {
+    const { resolved, stillPending } = matchPendingChannels(
+      [p("kanban-keeper", "#agent-kanban-keeper")],
+      [chan("agent-kanban-keeper", "C1", true)],
+    );
+    assert.deepEqual(resolved, [{ slug: "kanban-keeper", channelId: "C1" }]);
+    assert.equal(stillPending.length, 0);
+  });
+
+  test("a channel absent from the snapshot stays pending", () => {
+    const { resolved, stillPending } = matchPendingChannels([p("x", "not-created-yet")], [chan("other", "C9", true)]);
+    assert.equal(resolved.length, 0);
+    assert.equal(stillPending.length, 1);
+  });
+
+  test("private channel (only listed once a member) resolves", () => {
+    // Slack only returns a private channel in conversations.list when the bot is
+    // a member, so its presence with isMember=true is the normal resolve path.
+    const { resolved } = matchPendingChannels([p("sec", "#private-sec")], [chan("private-sec", "CP", true, true)]);
+    assert.deepEqual(resolved, [{ slug: "sec", channelId: "CP" }]);
+  });
+
+  test("a raw channel id in config is taken as-is (operator-wired; membership is theirs)", () => {
+    const { resolved, stillPending } = matchPendingChannels([p("x", "C0123ABC")], []);
+    assert.deepEqual(resolved, [{ slug: "x", channelId: "C0123ABC" }]);
+    assert.equal(stillPending.length, 0);
+  });
+
+  test("'#name' and bare 'name' resolve identically", () => {
+    const withHash = matchPendingChannels([p("a", "#foo")], [chan("foo", "C1", true)]);
+    const bare = matchPendingChannels([p("a", "foo")], [chan("foo", "C1", true)]);
+    assert.deepEqual(withHash.resolved, bare.resolved);
+  });
+
+  test("mixed roster in ONE snapshot: members resolve, non-members and absent ones pend", () => {
+    const { resolved, stillPending } = matchPendingChannels(
+      [p("a", "aa"), p("b", "bb"), p("c", "cc")],
+      [chan("aa", "CA", true), chan("bb", "CB", false)], // cc absent entirely
+    );
+    assert.deepEqual(resolved, [{ slug: "a", channelId: "CA" }]);
+    assert.deepEqual(
+      stillPending.map((a) => a.slug).sort(),
+      ["b", "c"],
+    );
+  });
+
+  test("promote-once: resolved agents are removed from stillPending, so the next pass can't re-resolve (no double-tail)", () => {
+    let pending: PendingAgent[] = [p("a", "aa"), p("b", "bb")];
+    // pass 1: only aa's channel is ready
+    let r = matchPendingChannels(pending, [chan("aa", "CA", true)]);
+    pending = r.stillPending;
+    assert.deepEqual(r.resolved, [{ slug: "a", channelId: "CA" }]);
+    assert.deepEqual(pending.map((x) => x.slug), ["b"]);
+    // pass 2: aa is STILL in the (now larger) snapshot, but it left `pending`,
+    // so it is not resolved a second time — only the newly-ready bb is.
+    r = matchPendingChannels(pending, [chan("aa", "CA", true), chan("bb", "CB", true)]);
+    assert.deepEqual(r.resolved, [{ slug: "b", channelId: "CB" }]);
+    assert.equal(r.stillPending.length, 0);
+  });
+
+  test("empty pending set resolves to nothing (loop can stop)", () => {
+    const { resolved, stillPending } = matchPendingChannels([], [chan("aa", "CA", true)]);
+    assert.equal(resolved.length, 0);
+    assert.equal(stillPending.length, 0);
+  });
+});
diff --git a/cli/src/slack/bridge.ts b/cli/src/slack/bridge.ts
index ff14cd9..3351f7f 100644
--- a/cli/src/slack/bridge.ts
+++ b/cli/src/slack/bridge.ts
@@ -1,7 +1,8 @@
 import { existsSync, statSync, openSync, readSync, closeSync } from "node:fs";
 import { join } from "node:path";
 import { SocketModeClient } from "@slack/socket-mode";
-import { SlackClient } from "./client.js";
+import { SlackClient, SlackChannelInfo } from "./client.js";
+import { matchPendingChannels, PendingAgent } from "./reresolve.js";
 import { routeSlackMessage, prefixAuthor, ChannelMapping } from "./inbound.js";
 import { formatTranscriptLines, formatCodexRolloutLines, TERMINAL_STOP_REASONS } from "./format.js";
 import { loadAgentsConfig } from "../agents/config.js";
@@ -217,12 +218,14 @@ export async function runSlackBridge(opts: BridgeOptions): Promise<void> {
     list.splice(i, 1); // consume so a genuine resend later is not swallowed
     return true;
   };
-  for (const a of agents) {
-    const channelId = await client.resolveChannelId(a.slackChannel!);
-    if (!channelId) {
-      console.error(`Slack channel not found for ${a.slug}: ${a.slackChannel}`);
-      continue;
-    }
+  // Build a tail + channel→agent mapping for one agent whose channel is known
+  // and joinable. Used for agents resolved at startup AND, later, for agents
+  // whose channel only becomes usable after the bridge started (the pending
+  // re-resolution loop below). Appends live to `tails`/`mapping`, which the poll
+  // loop and inbound router read by reference, so a late add needs no restart.
+  const agentBySlug = new Map(agents.map((a) => [a.slug, a] as const));
+  const buildTail = (a: (typeof agents)[number], channelId: string): void => {
+    if (tails.some((t) => t.slug === a.slug)) return; // promote-once: never double-tail
     mapping[channelId] = a.slug;
     const runtime = (a.runtime ?? "claude") as Runtime;
     const sessionId = agentIdentity(a.slug, runtime).sessionId;
@@ -230,6 +233,21 @@ export async function runSlackBridge(opts: BridgeOptions): Promise<void> {
     const path = runtime === "codex" ? findCodexRollout(cwd) : findSessionJsonl(sessionId);
     // Start at EOF so we mirror only new activity, not the whole backlog.
     tails.push({ slug: a.slug, runtime, sessionId, cwd, channelId, path, offset: path ? statSync(path).size : 0 });
+  };
+
+  // Resolve every agent against ONE conversations.list snapshot, gating on bot
+  // MEMBERSHIP: a public channel is listed the moment it exists — before the bot
+  // is invited — so mirroring on mere presence would post into a channel the bot
+  // can't write to and gets no events from (a silent agent — exactly #677).
+  // Agents that don't resolve (channel absent, or bot not a member yet) go to
+  // `pending` and are retried by the loop below, so a channel created/invited
+  // AFTER this restart is picked up with no manual restart.
+  let pending: PendingAgent[] = agents.map((a) => ({ slug: a.slug, channel: a.slackChannel! }));
+  {
+    const snapshot = await client.listChannels();
+    const { resolved, stillPending } = matchPendingChannels(pending, snapshot);
+    pending = stillPending;
+    for (const r of resolved) buildTail(agentBySlug.get(r.slug)!, r.channelId);
   }
 
   // Per-agent active "working…" pill. Set on each tool/thinking post, cleared
@@ -497,10 +515,14 @@ export async function runSlackBridge(opts: BridgeOptions): Promise<void> {
   // avoid send-keys-ing into a session that does not have this UI.
   const pickerByAgent = new Map<string, PickerState>();
   const PICKER_POLL_MS = 1000;
-  const claudeAgents = tails.filter((t) => t.runtime === "claude");
-  if (claudeAgents.length) {
+  // Schedule unconditionally and iterate `tails` live each tick so a Claude
+  // agent whose channel resolves AFTER startup (pending loop below) still gets
+  // pickers — a once-built `tails.filter(...)` snapshot would skip it, and zero
+  // Claude agents at boot would mean the interval was never scheduled at all.
+  {
     setInterval(async () => {
-      for (const t of claudeAgents) {
+      for (const t of tails) {
+        if (t.runtime !== "claude") continue;
         const pane = captureTmuxPane(t.slug);
         if (!pane) continue;
         const picker = parsePicker(pane);
@@ -708,8 +730,58 @@ export async function runSlackBridge(opts: BridgeOptions): Promise<void> {
       }
     }
   });
+  // ── Pending-channel re-resolution: the #677 self-heal ───────────────────
+  // Retry pending agents against a fresh snapshot on a SELF-RESCHEDULING timer
+  // (not setInterval — overlapping ticks under Slack rate-limiting could both
+  // see an agent pending and double-append its tail). The chain re-arms only
+  // while agents remain pending, so it costs nothing once all are mirrored, and
+  // pulls ONE conversations.list snapshot per pass shared across all pending
+  // agents. A channel created (or the bot invited) after this restart is picked
+  // up within one interval — no manual `systemctl restart` (issue #677).
+  const RESOLVE_RETRY_MS = 60_000;
+  const resolvePendingOnce = async (): Promise<void> => {
+    if (!pending.length) return;
+    let snapshot: SlackChannelInfo[];
+    try {
+      snapshot = await client.listChannels();
+    } catch (e) {
+      console.error("pending-resolve listChannels failed (will retry):", e);
+      return;
+    }
+    const { resolved, stillPending } = matchPendingChannels(pending, snapshot);
+    pending = stillPending;
+    for (const r of resolved) {
+      const a = agentBySlug.get(r.slug);
+      if (!a) continue;
+      buildTail(a, r.channelId);
+      console.error(`now mirroring ${r.slug}: channel ${a.slackChannel} became reachable (no restart).`);
+    }
+  };
+  const schedulePendingResolve = (): void => {
+    if (!pending.length) return;
+    setTimeout(() => {
+      // Always re-arm (while agents remain pending) even if a pass throws — an
+      // unexpected error in one pass must not silently kill the self-heal chain.
+      resolvePendingOnce()
+        .catch((e) => console.error("pending-resolve pass failed (will retry):", e))
+        .finally(() => schedulePendingResolve());
+    }, RESOLVE_RETRY_MS);
+  };
+  if (pending.length) {
+    // One log line for the whole pending set (not one per agent per tick) so a
+    // permanently-misconfigured channel doesn't spam the journal every pass.
+    console.error(
+      `${pending.length} agent(s) awaiting a reachable Slack channel (created + bot invited): ${pending
+        .map((p) => p.slug)
+        .join(", ")}. Retrying every ${RESOLVE_RETRY_MS / 1000}s.`,
+    );
+    schedulePendingResolve();
+  }
+
   await socket.start();
-  console.error(`Slack bridge connected. Mirroring ${tails.length} agent(s).`);
+  console.error(
+    `Slack bridge connected. Mirroring ${tails.length} agent(s)${pending.length ? `; ${pending.length} pending channel(s).` : "."}`,
+  );
 
   // Drop attachments older than the retention window so the inbox does not
   // grow without bound. We sweep on startup and then every hour. Override the
diff --git a/cli/src/slack/client.ts b/cli/src/slack/client.ts
index 366a587..8f8f5f3 100644
--- a/cli/src/slack/client.ts
+++ b/cli/src/slack/client.ts
@@ -1,5 +1,15 @@
 import { WebClient } from "@slack/web-api";
 
+/// One channel from a `conversations.list` snapshot. `isMember` reflects whether
+/// THIS bot token is in the channel — the bridge gates mirroring on it because a
+/// public channel is listed before the bot is invited (see matchPendingChannels).
+export interface SlackChannelInfo {
+  id: string;
+  name: string;
+  isMember: boolean;
+  isPrivate: boolean;
+}
+
 /// Thin wrapper over the Slack Web API for what the bridge needs: identify the
 /// bot, post messages, and resolve channel names to ids.
 export class SlackClient {
@@ -96,4 +106,29 @@ export class SlackClient {
     } while (cursor);
     return undefined;
   }
+
+  /// Page through every channel the bot can see in one pass and return a flat
+  /// snapshot (id + name + membership). Public channels are returned regardless
+  /// of membership (with isMember=false until the bot is invited); private
+  /// channels only where the bot is already a member. The bridge calls this once
+  /// per re-resolution pass and matches ALL pending agents against the single
+  /// snapshot, rather than a paginated lookup per agent.
+  async listChannels(): Promise<SlackChannelInfo[]> {
+    const out: SlackChannelInfo[] = [];
+    let cursor: string | undefined;
+    do {
+      const r = await this.web.conversations.list({
+        types: "public_channel,private_channel",
+        limit: 1000,
+        cursor,
+      });
+      for (const c of (r.channels ?? []) as any[]) {
+        if (c?.id && typeof c.name === "string") {
+          out.push({ id: c.id, name: c.name, isMember: !!c.is_member, isPrivate: !!c.is_private });
+        }
+      }
+      cursor = r.response_metadata?.next_cursor || undefined;
+    } while (cursor);
+    return out;
+  }
 }
diff --git a/cli/src/slack/reresolve.ts b/cli/src/slack/reresolve.ts
new file mode 100644
index 0000000..f901807
--- /dev/null
+++ b/cli/src/slack/reresolve.ts
@@ -0,0 +1,54 @@
+import type { SlackChannelInfo } from "./client.js";
+
+/// A roster agent that wants Slack mirroring but whose channel is not yet
+/// usable — the channel does not exist yet, or the bot has not been invited.
+/// Held in the bridge's `pending` set and retried against fresh channel
+/// snapshots until it becomes mirrorable, so a channel created (or a bot
+/// invited) AFTER the bridge last started is picked up without a restart.
+export interface PendingAgent {
+  slug: string;
+  /// The agent's configured slackChannel: "#name", "name", or a raw id.
+  channel: string;
+}
+
+export interface ResolvedAgent {
+  slug: string;
+  channelId: string;
+}
+
+/// Match pending agents against a single channel snapshot (one
+/// `conversations.list` page-through per pass, shared across all pending
+/// agents — never a lookup per agent, which would throttle the token bucket
+/// the post/pill path also uses).
+///
+/// An agent resolves ONLY when its channel is found AND the bot is a member.
+/// `conversations.list` returns a PUBLIC channel as soon as it exists — before
+/// the bot is invited — so promoting on mere presence would mirror a channel
+/// the bot cannot post to (`not_in_channel`) and receives no message events
+/// from: a silent half-mirrored agent, the exact bug this guards against. A
+/// PRIVATE channel is only listed once the bot is a member, so the gate is
+/// implied there. A raw channel id in the config is taken as-is (the operator
+/// wired it explicitly; membership is their responsibility), mirroring
+/// `resolveChannelId`.
+///
+/// Resolved agents are removed from the returned `stillPending` set, so the
+/// caller's next pass never re-resolves them (promote-once).
+export function matchPendingChannels(
+  pending: PendingAgent[],
+  channels: SlackChannelInfo[],
+): { resolved: ResolvedAgent[]; stillPending: PendingAgent[] } {
+  const byName = new Map<string, SlackChannelInfo>();
+  for (const c of channels) byName.set(c.name, c);
+  const resolved: ResolvedAgent[] = [];
+  const stillPending: PendingAgent[] = [];
+  for (const a of pending) {
+    if (/^[CG][A-Z0-9]+$/.test(a.channel)) {
+      resolved.push({ slug: a.slug, channelId: a.channel });
+      continue;
+    }
+    const hit = byName.get(a.channel.replace(/^#/, ""));
+    if (hit && hit.isMember) resolved.push({ slug: a.slug, channelId: hit.id });
+    else stillPending.push(a);
+  }
+  return { resolved, stillPending };
+}