fleetd #184: report member trust model

The correction removed a false claim (blocking the socket breaks git over
SSH) but took a true one with it: the socket is a live handle to the agent,
so a member holding it can sign with every key the agent holds. Without that,
the entry reads as if the setting does not matter, and an operator has no
reason left not to set it to allow. Fixing an overclaim must not leave an
underclaim.

Also record the measurement and the mistake behind the old claim, so the next
person does not re-argue it from scratch.

deploy/fleetd.service

@@ -31,11 +31,27 @@ Environment=HERDR_SOCKET_PATH=%h/.config/herdr/herdr.sock
 # spawns, so this line decides whether the fleet can run a build at all. systemd does not source a
 # login shell, so without it the daemon — and every worker — gets a bare default with no JDK/Maven.
 Environment=PATH=/usr/lib/jvm/temurin-25-jdk/bin:/usr/share/maven/bin:/usr/local/bin:/usr/bin:/bin
-# Secrets are NOT set here — this file is committed. Put the API/worker tokens in a private
-# drop-in that systemd reads with restrictive permissions:
-#   systemctl --user edit fleetd     →  [Service] / Environment=FLEETD_API_TOKEN=...
-# or point EnvironmentFile at a 0600 file:
+# Secrets are NOT set here — this file is committed. Put ALL three tokens in a private drop-in
+# that systemd reads with restrictive permissions. In `systemctl --user edit fleetd`, add:
+#   [Service]
+#   Environment=FLEETD_API_TOKEN=...
+#   Environment=WORKER_GITEA_TOKEN=...
+#   Environment=AI_GATEWAY_TOKEN=...
+# FLEETD_API_TOKEN protects fleetd's API. WORKER_GITEA_TOKEN lets members open pull requests; if
+# it is missing, fleetd still starts, but a member fails when it later tries to open a pull request.
+# AI_GATEWAY_TOKEN authenticates gateway profiles; if it is missing, fleetd still starts, but a
+# gateway profile later returns HTTP 401. Or, put the same three variables in a 0600 file and add:
 # EnvironmentFile=%h/.config/fleetd/env
+# After starting, check which of them actually resolved. The daemon reports every secret a
+# configured profile references, by name, never by value:
+#   journalctl --user -u fleetd | grep 'startup secret'
+# A resolved one logs "startup secret NAME: set (profile 'x' tokenEnv)". A missing one logs
+# "startup secret NAME: MISSING" at WARN — and the daemon starts anyway, which is the whole
+# problem: without this grep the first sign is a member that cannot open a pull request, hours
+# later and in a different component.
+# Note what the report can and cannot tell you. It lists only names some profile actually
+# references (tokenEnv, gitTokenEnv, and the broker uriEnv). A secret nothing references is never
+# reported, because nothing needs it.
 
 Restart=on-failure
 RestartSec=10s

fleetd/fleetd.example.yaml

@@ -307,16 +307,22 @@ profiles:
     #   and no refusal on cost; the cap on live members is the single thing standing between a
     #   fan-out and your monthly limit. Set it deliberately and keep it small.
     #
-    #   GOTCHA 3 (fleetd #176) — `maxLoad` counts members, never the lead itself. The lead is a live
-    #   `claude` session on this SAME account (a lead is never moved off-subscription, whatever its
-    #   own profile says), so it already holds one seat before any member spawns. If a lead's
-    #   `fleet.leaders.<name>.profile` names THIS profile — or ANY OTHER `subscription: true`
-    #   profile that shares this one's account (see THE SENTINEL, just below, next to
-    #   `credentialId:`) — `fleet_list`'s `free` for this profile subtracts that lead's live
-    #   seat(s) automatically; see `profile:` under THE FLEET below. If no lead entry names a
-    #   profile sharing this account, fleetd has no way to know a lead holds a seat here, and `free`
-    #   will overstate what a fresh `fleet_spawn` actually gets by exactly the seats the lead is
-    #   quietly holding.
+    #   GOTCHA 3 (fleetd #176, corrected by fleetd #257) — `maxLoad` counts members, never the lead
+    #   itself. The lead is a live `claude` session on this SAME account (a lead is never moved
+    #   off-subscription, whatever its own profile says), so it already holds one seat before any
+    #   member spawns. If a lead's `fleet.leaders.<name>.profile` names THIS profile — or ANY OTHER
+    #   `subscription: true` profile that shares this one's account (see THE SENTINEL, just below,
+    #   next to `credentialId:`) — `fleet_list` reports that seat count under `leadSeats`; see
+    #   `profile:` under THE FLEET below. `free` itself is NEVER reduced by `leadSeats`: `free` means
+    #   "what the real placement gate (`CompositePeerLauncher#enforceMaxLoad`) will actually grant a
+    #   fresh `fleet_spawn` right now", and that gate only ever compares live members against
+    #   `maxLoad` — it has no notion of the lead's own seat. An earlier cut of this feature
+    #   subtracted `leadSeats` from `free` on the theory it made `free` describe the true ceiling on
+    #   the account, but no backend seat ceiling shared with the lead has ever actually been
+    #   measured, and the subtraction just made `free` disagree with the one thing it is supposed to
+    #   describe — the fleetd #257 fix. `maxLoad: 3` means 3 member slots, full stop; a lead sharing
+    #   the account is a fact you can see in `leadSeats`, not a reason `free` undercounts spawns that
+    #   will, in practice, succeed.
     #
     #   THE SENTINEL (fleetd #176 stage 2, correcting an inert stage 1 fix): every `subscription:
     #   true` profile that leaves `credentialId` unset shares ONE implicit account-wide credential
@@ -536,17 +542,18 @@ fleet:
   # auto-launched: it is also how fleetd learns which account this lead's own session shares. A
   # `subscription: true` profile bills the operator's Claude account, and the lead itself is always
   # a live `claude` session on that same account — `maxLoad` never counted that seat. If a lead
-  # entry here names a profile that shares a worker profile's account, `fleet_list`'s `free` for
-  # that worker profile subtracts the lead's live seat(s) automatically. "Shares the account" is
-  # decided by matching `effectiveCredentialId()`, which (fleetd #176 stage 2 — see THE SENTINEL,
-  # next to `credentialId:`, in THE WORKERS above) means: an explicit, matching `credentialId:` on
-  # both, OR — the common case, needing NO extra config — both being `subscription: true` with
-  # `credentialId` left unset, since those all share one implicit account-wide id. A lead on `opus`
-  # and workers on `sonnet` link automatically this way; they do NOT need the same profile name.
-  # Setting `profile:` on an already-running, recognise-only lead is safe — the daemon only launches
-  # the SHORTFALL below `instances`, so naming a profile here does not, by itself, start anything.
-  # Omit it and fleetd has no way to derive the sharing — there is no other reliable signal on the
-  # daemon's side — so that lead's seat goes uncounted, exactly as before this ticket.
+  # entry here names a profile that shares a worker profile's account, `fleet_list` reports the
+  # lead's live seat(s) on that worker profile under `leadSeats` — informational only, as of fleetd
+  # #257 it is NEVER subtracted from `free` (see GOTCHA 3, next to `maxLoad:`, in THE WORKERS above,
+  # for why). "Shares the account" is decided by matching `effectiveCredentialId()`, which (fleetd
+  # #176 stage 2 — see THE SENTINEL, next to `credentialId:`, in THE WORKERS above) means: an
+  # explicit, matching `credentialId:` on both, OR — the common case, needing NO extra config — both
+  # being `subscription: true` with `credentialId` left unset, since those all share one implicit
+  # account-wide id. A lead on `opus` and workers on `sonnet` link automatically this way; they do
+  # NOT need the same profile name. Setting `profile:` on an already-running, recognise-only lead is
+  # safe — the daemon only launches the SHORTFALL below `instances`, so naming a profile here does
+  # not, by itself, start anything. Omit it and fleetd has no way to derive the sharing — there is
+  # no other reliable signal on the daemon's side — so that lead's seat never appears in `leadSeats`.
   #
   # `tab:` (CB-579) is REQUIRED and is the only field identity depends on — the exact label of the
   # tab hosting the lead, matched case-insensitively. Label the tab yourself and put that same
@@ -669,13 +676,28 @@ guard:
 #            every name here NOT also in `allow` is overlaid with a non-secret sentinel value before
 #            the pane's login shell runs — real protection only for names that shell does not itself
 #            re-export (see the ROUND-2 CORRECTION note above). Under allow-list: reporting only.
-#   sshAuthSock → whether SSH_AUTH_SOCK may pass through under allow-list ("allow") or must be
-#            blanked like any other non-derived name ("block", the default). This is a decision you
-#            have to make explicitly: SSH_AUTH_SOCK is a handle to YOUR ssh-agent, and a member
-#            holding it can sign with your keys — it sits in no secret file and looks like no
-#            credential, which is why it slipped past three earlier tickets (gitea #110). Blocking
-#            it breaks git over SSH inside members (push/fetch authenticate as you); use HTTPS
-#            remotes or scoped deploy keys instead of allowing it lightly.
+#   sshAuthSock → whether SSH_AUTH_SOCK may pass through under allow-list ("allow") or is omitted
+#            from the member environment ("block", the default). Blocking it only omits the
+#            inherited ssh-agent path. It discourages automatic use of the operator's agent.
+#            It does not deny same-user access to that socket. It also does not block SSH keys that
+#            are readable on disk. Git over SSH may still work from inside a member. Keep the block:
+#            it is correct and costs nothing, but it is not a control. A member runs as the same OS
+#            user as the lead. Inside one uid, ordinary Unix permissions provide no meaningful
+#            confidentiality boundary. A real boundary needs a different OS user or OS-level
+#            confinement, such as a container or VM. That is the open question in fleetd #184.
+#
+#            Still do not set this to "allow" casually. SSH_AUTH_SOCK is a live handle to YOUR
+#            ssh-agent, so a member holding it can sign with EVERY key the agent holds. It sits in
+#            no secret file and looks like no credential, which is why it slipped past three
+#            earlier tickets (gitea #110). Blocking it does not contain a member, but allowing it
+#            hands one a signing capability for no gain — the block costs nothing, so keep it.
+#
+#            Both halves of this are measured, not argued. 2026-08-28: a member with
+#            SSH_AUTH_SOCK blanked pushed to the forge over SSH successfully, because `ssh -G`
+#            resolves an IdentityFile outside ~/.ssh that is readable and has no passphrase. An
+#            earlier version of this comment claimed blocking the socket BREAKS git over SSH. It
+#            does not. That claim came from looking only in ~/.ssh, which holds nothing but four
+#            `Include` lines — looking in one place and concluding about the whole host.
 #
 # HOT-RELOADABLE the same way `fleet:` is (CB-559): read fresh on every spawn, so editing this list
 # and reloading config (or restarting) changes what the NEXT spawn inherits; already-running members

fleetd/src/main/java/dev/ltms/fleet/Fleetd.java

@@ -121,6 +121,7 @@ public final class Fleetd {
         // else can fail on a silently-empty one. A daemon started without a login shell (launchd)
         // boots fine either way — this is the only thing that says so out loud.
         reportRequiredSecrets(cfg);
+        reportMemberTrustModel(cfg);
         // CB-596: an absent (or empty) memberCredentials: block blocks NOTHING — no credential
         // name is hardcoded any more to fall back on. Say so loudly, the same way a missing
         // secret is reported above, so upgrading past this commit never silently drops CB-592's
@@ -1136,6 +1137,24 @@ public final class Fleetd {
         });
     }
 
+    /**
+     * fleetd #184: state the member trust model at startup. Environment controls and worktrees do
+     * not make a sandbox when fleetd and its members use the same OS user. A separate herdr may
+     * provide that boundary, but fleetd cannot inspect the uid at the other end of its socket.
+     */
+    static void reportMemberTrustModel(FleetConfig cfg) {
+        if (cfg.memberHerdrSocket() != null && !cfg.memberHerdrSocket().isBlank()) {
+            log.info("member trust model: members are routed to a separate herdr through "
+                    + "memberHerdrSocket. fleetd cannot see that herdr's uid, so confirm it runs "
+                    + "as a different OS user before treating it as a boundary.");
+            return;
+        }
+        log.info("member trust model: members run as the same OS user as fleetd, not in a sandbox. "
+                + "A member can read any file this user can read, including SSH keys and credential "
+                + "stores, whatever memberCredentials says. To add a real boundary, route members to "
+                + "a second herdr under a different OS user with memberHerdrSocket.");
+    }
+
     /**
      * CB-596: {@code known:} empty (block absent entirely, or present but empty) means {@link
      * FleetConfig.MemberCredentials#blockedSet()} is empty too — every member pane inherits the

fleetd/src/main/java/dev/ltms/fleet/mcp/FleetMcp.java

@@ -139,16 +139,24 @@ public final class FleetMcp {
 
     /**
      * fleetd #176: the seats a profile's own live LEAD session(s) hold on the same Claude
-     * subscription — the third reason (alongside {@link QuarantineSource} and {@link OutageSource})
-     * {@code free} can overstate what a fresh {@code fleet_spawn} would actually get.
+     * subscription — a fact {@code fleet_list} reports alongside {@code free} via the
+     * {@code leadSeats} key.
      *
      * <p>{@code maxLoad} counts only <em>members</em>, never the lead itself. But a
      * {@code subscription: true} profile bills the operator's own Claude account, and the lead is
      * always a live {@code claude} session on that same account (it is never moved off-subscription
-     * — see {@code LeadLauncher}). So a fan-out that fills every member slot still leaves the lead's
-     * own seat unaccounted for, and the daemon reports a slot that was never really free. See
-     * {@code Fleetd.leadSeatLookup} for how the count is derived — from {@code fleet.leaders.<name>
-     * .profile} and each profile's {@code effectiveCredentialId()}, never a hardcoded constant.
+     * — see {@code LeadLauncher}). See {@code Fleetd.leadSeatLookup} for how the count is derived —
+     * from {@code fleet.leaders.<name>.profile} and each profile's {@code effectiveCredentialId()},
+     * never a hardcoded constant.
+     *
+     * <p>fleetd #257: this count is reported, never subtracted from {@code free}. An earlier cut of
+     * this feature subtracted it, on the theory that it made {@code free} describe the real ceiling
+     * on the account — but the real spawn gate ({@code CompositePeerLauncher#enforceMaxLoad}) never
+     * read this count at all, so the subtraction made {@code free} disagree with the one thing it is
+     * supposed to describe: what a fresh {@code fleet_spawn} will actually get. No backend seat
+     * ceiling shared with the lead has been measured either — see {@code fleetd.example.yaml}'s
+     * {@code maxLoad} docs. {@code free} now always equals {@code max(0, maxLoad - live)}, and
+     * {@code leadSeats} is reported purely as a fact the caller may act on however it likes.
      */
     public record LeadSeatSource(Function<String, Integer> seatsFor) {
         /** Inert source — no profile is ever reported as sharing a seat with a lead. */
@@ -1137,10 +1145,17 @@ public final class FleetMcp {
      * <p>fleetd #176: {@code maxLoad} counts panes, not subscription seats — it never counted the
      * lead's own seat on a {@code subscription: true} profile's account. {@link LeadSeatSource}
      * reports that count (0 for a non-subscription profile, or when no live lead shares its
-     * credential), and it is subtracted from {@code free} the same way {@code live} already is —
-     * {@code maxLoad} itself is left untouched, so the row still reports the configured cap. The
-     * {@code leadSeats} key is added only when the count is positive, for the same
-     * byte-identical-when-unused reason as the quarantine/cool-off keys above.
+     * credential) via the {@code leadSeats} key, added only when the count is positive, for the
+     * same byte-identical-when-unused reason as the quarantine/cool-off keys above.
+     *
+     * <p>fleetd #257: {@code leadSeatCount} is reported, never subtracted from {@code free}.
+     * {@code free} means "what a fresh {@code fleet_spawn} on this profile will actually get", and
+     * the real gate ({@code CompositePeerLauncher#enforceMaxLoad}) only ever compares {@code live}
+     * against {@code maxLoad} — it has no notion of a lead's own seat. Subtracting
+     * {@code leadSeatCount} here made {@code free} disagree with the gate it is supposed to
+     * describe: it could report {@code free: 0} while a spawn on that exact profile still
+     * succeeded. {@code leadSeats} stays in the row as a fact the caller can act on however it
+     * likes, but it no longer changes what {@code free} means.
      */
     private static Map<String, Object> capacityView(String profile, Function<String, Integer> liveCount,
                                                      Function<String, Integer> maxLoad, List<MemberSession> roster,
@@ -1155,7 +1170,12 @@ public final class FleetMcp {
                 .count();
         Map<String, Object> row = new LinkedHashMap<>();
         row.put("profile", profile); row.put("maxLoad", cap); row.put("live", live);
-        row.put("free", cap == null ? null : Math.max(0, cap - live - leadSeatCount));
+        // fleetd #257: free must report what the real spawn gate (CompositePeerLauncher#enforceMaxLoad)
+        // will actually grant, and that gate never reads leadSeatCount — only maxLoad and live. Not
+        // subtracting the lead's seat here used to make free UNDERSTATE what a fresh fleet_spawn would
+        // get, so a lead believing free:0 gave up on a profile the gate would still spawn onto.
+        // leadSeatCount is still reported via the leadSeats key below, just never subtracted from free.
+        row.put("free", cap == null ? null : Math.max(0, cap - live));
         row.put("reclaimable", reclaimable);
         if (leadSeatCount > 0) {
             row.put("leadSeats", leadSeatCount);
@@ -1360,8 +1380,13 @@ public final class FleetMcp {
                         + "member spawned without one shares its directory with others and never reports "
                         + "an id, however long it runs (fleetd #249). An empty 'members' "
                         + "means no members are spawned; it says nothing about peers. When capacity "
-                        + "facts are configured, a 'capacity' row per profile also reports free: 0 for "
-                        + "a quarantined profile's credential (see fleet_profiles), whatever its "
+                        + "facts are configured, a 'capacity' row per profile reports 'free' — the "
+                        + "slots a fresh fleet_spawn on that profile will actually be granted right "
+                        + "now (max(0, maxLoad - live)), the same check the spawn gate itself runs. A "
+                        + "'leadSeats' key, when present, reports how many of those live slots are a "
+                        + "lead session sharing this profile's subscription — informational only, "
+                        + "already NOT subtracted from 'free' (fleetd #257). It also reports free: 0 "
+                        + "for a quarantined profile's credential (see fleet_profiles), whatever its "
                         + "maxLoad/live — with credentialId and quarantinedForSeconds naming the "
                         + "quarantine, so 'free: 0, busy' can be told apart from 'free: 0, refusing "
                         + "for N seconds'.",

fleetd/src/test/java/dev/ltms/fleet/MemberTrustModelReportTest.java

@@ -0,0 +1,73 @@
+package dev.ltms.fleet;
+
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+import dev.ltms.fleet.config.FleetConfig;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+import org.slf4j.LoggerFactory;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * fleetd #184: startup must state whether members share fleetd's OS user or use a separate herdr.
+ */
+class MemberTrustModelReportTest {
+
+    private static FleetConfig load(Path dir, String yaml) throws Exception {
+        Path f = dir.resolve("fleetd.yaml");
+        Files.writeString(f, yaml);
+        return FleetConfig.load(f);
+    }
+
+    private static ListAppender<ILoggingEvent> attach() {
+        Logger logger = (Logger) LoggerFactory.getLogger(Fleetd.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        return appender;
+    }
+
+    private static void detach(ListAppender<ILoggingEvent> appender) {
+        ((Logger) LoggerFactory.getLogger(Fleetd.class)).detachAppender(appender);
+    }
+
+    private static String report(FleetConfig cfg) {
+        Logger logger = (Logger) LoggerFactory.getLogger(Fleetd.class);
+        ch.qos.logback.classic.Level original = logger.getLevel();
+        logger.setLevel(ch.qos.logback.classic.Level.INFO);
+        ListAppender<ILoggingEvent> appender = attach();
+        try {
+            Fleetd.reportMemberTrustModel(cfg);
+        } finally {
+            detach(appender);
+            logger.setLevel(original);
+        }
+        return appender.list.getFirst().getFormattedMessage();
+    }
+
+    @Test
+    void unsetMemberHerdrSocketStatesThatMembersAreNotSandboxed(@TempDir Path dir) throws Exception {
+        FleetConfig cfg = load(dir, "bind:\n  host: 127.0.0.1\n  port: 8765\n");
+
+        assertEquals("member trust model: members run as the same OS user as fleetd, not in a sandbox. "
+                        + "A member can read any file this user can read, including SSH keys and credential "
+                        + "stores, whatever memberCredentials says. To add a real boundary, route members to "
+                        + "a second herdr under a different OS user with memberHerdrSocket.",
+                report(cfg));
+    }
+
+    @Test
+    void configuredMemberHerdrSocketStatesThatFleetdCannotConfirmTheBoundary(@TempDir Path dir) throws Exception {
+        FleetConfig cfg = load(dir, "memberHerdrSocket: /tmp/member-herdr.sock\n");
+
+        assertEquals("member trust model: members are routed to a separate herdr through "
+                        + "memberHerdrSocket. fleetd cannot see that herdr's uid, so confirm it runs "
+                        + "as a different OS user before treating it as a boundary.",
+                report(cfg));
+    }
+}

fleetd/src/test/java/dev/ltms/fleet/mcp/FleetMcpTest.java

@@ -34,6 +34,7 @@ import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Function;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -810,13 +811,16 @@ class FleetMcpTest {
     }
 
     /**
-     * fleetd #176: this is the exact shape measured on the Mac fleet — {@code maxLoad:3, live:2},
-     * where one of the "free" three is really the lead's own seat on the same subscription. The old
-     * formula ({@code max(0, cap - live)}) reported {@code free:1}; the real ceiling is {@code 0}
-     * (two members plus the lead's own seat already fill all three).
+     * fleetd #257: this is the exact shape measured on the Mac fleet — {@code maxLoad:3, live:2},
+     * one lead sharing the subscription. The OLD formula ({@code max(0, cap - live - leadSeats)})
+     * reported {@code free:0} here, disagreeing with the real spawn gate (which never read
+     * {@code leadSeats} and would still grant one more spawn — see
+     * {@code freeMatchesWhatTheRealPlacementGateActuallyGrants} below for that proof against the
+     * actual gate). {@code free} must report {@code 1}: {@code leadSeats} is carried as a fact, not
+     * subtracted.
      */
     @Test
-    void leadSeatSubtractsFromFreeTheSameWayLiveDoes() {
+    void leadSeatIsReportedButNeverSubtractedFromFree() {
         FakeHerdr h = new FakeHerdr();
         SessionManager sessions = new SessionManager(workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")));
         FleetMcp.LeadSeatSource leadSeats = new FleetMcp.LeadSeatSource(
@@ -829,17 +833,17 @@ class FleetMcpTest {
 
         assertTrue(out.contains("\"maxLoad\":3"), "maxLoad itself must be left untouched: " + out);
         assertTrue(out.contains("\"live\":2"), out);
-        assertTrue(out.contains("\"free\":0"), "2 live + 1 lead seat fills all 3: " + out);
-        assertTrue(out.contains("\"leadSeats\":1"), out);
+        assertTrue(out.contains("\"free\":1"), "free is maxLoad - live only, never minus leadSeats: " + out);
+        assertTrue(out.contains("\"leadSeats\":1"), "leadSeats is still reported, just not subtracted: " + out);
     }
 
     /**
-     * fleetd #176: the OTHER measurement in the issue — a completely idle fleet still overstates
-     * {@code free} by the lead's own seat. {@code maxLoad:3, live:0} must report {@code free:2}, the
-     * real fan-out ceiling, not {@code 3}.
+     * fleetd #257: the OTHER measurement in the issue — a completely idle fleet with a lead sharing
+     * the subscription. {@code maxLoad:3, live:0} must report {@code free:3}, matching what the
+     * spawn gate (which has no notion of a lead's seat) would actually grant.
      */
     @Test
-    void leadSeatLowersFreeOnAnOtherwiseIdleSubscriptionProfile() {
+    void leadSeatDoesNotLowerFreeOnAnOtherwiseIdleSubscriptionProfile() {
         FakeHerdr h = new FakeHerdr();
         SessionManager sessions = new SessionManager(workerService(h, "http://gx00.gw:8000", Set.of("gx00.gw")));
         FleetMcp.LeadSeatSource leadSeats = new FleetMcp.LeadSeatSource(
@@ -851,10 +855,76 @@ class FleetMcpTest {
                 FleetMcp.QuarantineSource.none(), FleetMcp.OutageSource.none(), leadSeats, Map.of(), "", null));
 
         assertTrue(out.contains("\"live\":0"), out);
-        assertTrue(out.contains("\"free\":2"), "an idle fleet's real ceiling is 3 minus the lead's own seat: " + out);
+        assertTrue(out.contains("\"free\":3"), "the real gate never subtracts the lead's seat: " + out);
         assertTrue(out.contains("\"leadSeats\":1"), out);
     }
 
+    /**
+     * fleetd #257 — the defect, driven against the REAL placement gate, not a copy of its
+     * arithmetic. {@code free} must equal exactly how many more spawns
+     * {@link CompositePeerLauncher#spawn} (routed through the same {@link SessionManager} fleet_spawn
+     * itself uses) will grant on this profile right now: this test reads whatever number
+     * {@code fleet_list}'s real {@code listFleet} call reports, then drives that many spawns through
+     * the REAL composite launcher and asserts every one succeeds, and the next one — one past what
+     * fleet_list promised — is refused. A test that instead hand-computed {@code cap - live} and
+     * compared it to {@code free} would pass even if both sides shared the same wrong formula (this
+     * repo has been bitten by exactly that before); this one only passes when fleet_list's number and
+     * the gate's real behaviour actually agree.
+     *
+     * <p>{@code liveCount} here is wired the same way {@code Fleetd.main} wires it in production: one
+     * function, read by both the {@link CompositePeerLauncher}'s {@code maxLoad} gate and
+     * {@code fleet_list}'s {@code CapacitySource}, off the SAME {@link SessionManager#roster()} — so
+     * the two paths cannot silently drift on what "live" means.
+     */
+    @Test
+    void freeMatchesWhatTheRealPlacementGateActuallyGrants() {
+        FakeHerdr h = new FakeHerdr();
+        FleetConfig.Profile wcfg = new FleetConfig.Profile(
+                "sonnet", "http://gx00.gw:8000", "coder", null, "FLEETD_WORKER_TOKEN", null,
+                "tab", "fleetd-workers", "worker: {profile} #{n}", null,
+                null, null, null, null, null, null, null, 3);
+        Map<String, FleetConfig.Profile> profiles = Map.of(wcfg.profile(), wcfg);
+        ClaudeCodeLauncher delegate = new ClaudeCodeLauncher(
+                new AgentControl(h), new WorkspaceControl(h), new SubscriptionGuard(Set.of("gx00.gw")),
+                profiles, wcfg.profile(), k -> "FLEETD_WORKER_TOKEN".equals(k) ? "tok" : null);
+
+        java.util.concurrent.atomic.AtomicReference<SessionManager> smRef =
+                new java.util.concurrent.atomic.AtomicReference<>();
+        Function<String, Integer> liveCount = profile -> (int) smRef.get().roster().stream()
+                .filter(s -> profile.equals(s.profile())).count();
+        CompositePeerLauncher composite = new CompositePeerLauncher(
+                List.of(delegate), wcfg.profile(), profiles, PlacementPolicies.fixed(), liveCount);
+        SessionManager sm = new SessionManager(composite);
+        smRef.set(sm);
+
+        // Two members already live — the exact shape measured in fleetd #257 (maxLoad:3, live:2).
+        assertFalse(FleetMcp.spawn(sm, "sonnet").isError(), "setup: first live member must spawn cleanly");
+        assertFalse(FleetMcp.spawn(sm, "sonnet").isError(), "setup: second live member must spawn cleanly");
+
+        // A lead session shares this profile's subscription — leadSeats:1, same as the ticket.
+        FleetMcp.LeadSeatSource leadSeats = new FleetMcp.LeadSeatSource(p -> "sonnet".equals(p) ? 1 : 0);
+        String out = textOf(FleetMcp.listFleet(composite, sm, null,
+                new FleetMcp.CapacitySource(liveCount, p -> profiles.get(p).maxLoad(), profiles::keySet, () -> 0),
+                new FleetMcp.HealthCoverageSource(() -> "off"), FleetMcp.QuarantineSource.none(),
+                FleetMcp.OutageSource.none(), leadSeats, Map.of(), "", null));
+        int reportedFree = extractInt(out, "free");
+
+        for (int i = 0; i < reportedFree; i++) {
+            McpSchema.CallToolResult res = FleetMcp.spawn(sm, "sonnet");
+            assertFalse(res.isError(), "fleet_list promised free:" + reportedFree + "; spawn #" + (i + 1)
+                    + " of that many was refused by the real gate: " + textOf(res));
+        }
+        McpSchema.CallToolResult overflow = FleetMcp.spawn(sm, "sonnet");
+        assertTrue(overflow.isError(), "fleet_list reported free:" + reportedFree
+                + " but the real placement gate granted at least one more spawn than that: " + textOf(overflow));
+    }
+
+    private static int extractInt(String json, String key) {
+        java.util.regex.Matcher m = java.util.regex.Pattern.compile("\"" + key + "\":(-?\\d+)").matcher(json);
+        assertTrue(m.find(), "no \"" + key + "\" field in: " + json);
+        return Integer.parseInt(m.group(1));
+    }
+
     /** A profile with no lead seats reported must be byte-identical to before this ticket. */
     @Test
     void zeroLeadSeatsOmitsTheKeyAndLeavesFreeUnchanged() {

fleetd/src/test/java/dev/ltms/fleet/session/FakeWorktrees.java

@@ -45,6 +45,9 @@ public final class FakeWorktrees implements Worktrees {
     private final List<String> overlayShareOrder = new CopyOnWriteArrayList<>();
     private final Set<String> existingPaths = ConcurrentHashMap.newKeySet();
     private final Set<String> trackedPaths = ConcurrentHashMap.newKeySet();
+    /** Worktree paths that currently exist, mirroring GitWorktrees' {@code Files.exists} check for
+     *  the already-gone case (CB-576 review, fleetd #116). */
+    private final Set<String> worktreePaths = ConcurrentHashMap.newKeySet();
     private final AtomicLong snapshotSeq = new AtomicLong();
     private volatile RuntimeException addFailure;
     private volatile RuntimeException snapshotFailure;
@@ -115,7 +118,15 @@ public final class FakeWorktrees implements Worktrees {
         }
         // The branch already carries a unique nonce, so the derived path is distinct per acquire
         // without an extra counter — keep it a pure function of the branch the test can predict.
-        return prefix + "/" + branch.replace('/', '_');
+        String path = prefix + "/" + branch.replace('/', '_');
+        worktreePaths.add(path);
+        return path;
+    }
+
+    /** Model an operator / {@code git worktree prune} removing the worktree before release. */
+    public FakeWorktrees markGone(String worktreePath) {
+        worktreePaths.remove(worktreePath);
+        return this;
     }
 
     @Override
@@ -125,6 +136,11 @@ public final class FakeWorktrees implements Worktrees {
 
     @Override
     public boolean hasUncommitted(String worktreePath) {
+        // A path that was never added, or was marked gone, is reported clean, mirroring
+        // GitWorktrees' already-gone guard — never an error, so teardown still completes.
+        if (!worktreePaths.contains(worktreePath)) {
+            return false;
+        }
         return dirty;
     }
 

fleetd/src/test/java/dev/ltms/fleet/session/WorktreeSessionManagerTest.java

@@ -258,6 +258,38 @@ class WorktreeSessionManagerTest {
         }
     }
 
+    /**
+     * CB-576 review (fleetd #116). A worktree that is already gone (operator cleanup,
+     * {@code git worktree prune}, an earlier half-completed release) must not break teardown.
+     * {@code hasUncommitted} reports the missing path clean (mirroring {@code GitWorktrees}), so
+     * {@code release} still runs {@code notifyReleased} (the CB-516 fast-fail for a blocked
+     * {@code fleet_send} caller) and {@code launcher.stop} (so the pane is not orphaned), and falls
+     * through to the already-gone-tolerant {@code remove}. Since CB-581 this all happens because the
+     * notify-and-stop work sits in {@code release}'s {@code finally}/post-try block rather than a
+     * checked branch — this test pins that shape by construction.
+     */
+    @Test
+    void releaseStillStopsPaneAndNotifiesWhenWorktreeIsGone() {
+        FakeHerdr herdr = new FakeHerdr();
+        FakeWorktrees worktrees = new FakeWorktrees().withRepoRoot("/repo").withPrefix("/wt");
+        SessionManager sessions = new SessionManager(workerService(herdr), worktrees);
+        List<SessionManager.ReleaseDetail> released = new java.util.concurrent.CopyOnWriteArrayList<>();
+        sessions.onRelease(released::add);
+        MemberSession s = sessions.acquire("ltms-local", null, "/caller/proj", null,
+                new WorktreeRequest("cb-576g", null));
+
+        worktrees.markGone(s.worktree());
+        sessions.release(s.paneId());
+
+        assertEquals(1, released.size(),
+                "notifyReleased must still fire when the worktree is already gone (CB-516)");
+        assertEquals(s.terminalId(), released.getFirst().terminalId());
+        assertTrue(herdr.called("pane.close"),
+                "the pane must still be stopped when the worktree is already gone");
+        assertEquals(1, worktrees.removeCalls().size(),
+                "release still calls the already-gone-tolerant remove");
+    }
+
     @Test
     void drainAllPreservesWorktreeOfIdleSession() {
         FakeHerdr herdr = new FakeHerdr();