diff --git a/CHANGELOG.md b/CHANGELOG.md
index de2549b..a1ffbdd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Never send a liveness signal to the host's own process when checking a persistence lease owner. On Windows, runtimes that emulate POSIX signals may treat `kill(pid, 0)` as a real termination, which matches reports of the OpenCode service dying silently with the plugin installed (#81).
+- On OpenCode 2, tear down everything a partially failed `setup` already started (event subscription, timers, hook registrations, and the goal core with its persistence lease) instead of leaking it on every location boot.
+- On Windows, treat `/` and `\` as the same separator when matching a location, so a reload with a differently spelled path retires the previous instance instead of running beside it.
 - Fix completion audits always failing on OpenCode 2.0.26. That host appends a `browser` deny rule to every agent, and the verifier ownership check compared permissions by exact JSON, so it rejected the plugin's own `goal-verify` agent and every completion was rejected. The check now accepts extra host-added deny rules, which only narrow access, and still rejects any changed, missing, reordered, allow or ask rule. Verified against live 2.0.16 and 2.0.26 hosts, including the foreign-verifier rejection mode.
 - When the auditor's prompt fails and no verdict reached the transcript, report `auditor prompt failed: <reason>` instead of the misleading "no single clear final-line verdict".
 
diff --git a/src/persistence-lease.js b/src/persistence-lease.js
index 2cddc99..4cd414f 100644
--- a/src/persistence-lease.js
+++ b/src/persistence-lease.js
@@ -103,6 +103,10 @@ function persistenceLeaseHardLinkError() {
 
 function processIsAlive(pid) {
   if (!Number.isSafeInteger(pid) || pid <= 0) return null
+  // The host process is alive by definition. Never signal it: runtimes that
+  // emulate POSIX signals on Windows may map signal 0 to a real termination,
+  // which would kill the OpenCode service silently (issue #81).
+  if (pid === process.pid) return true
   try {
     process.kill(pid, 0)
     return true
diff --git a/src/v2-bridge.js b/src/v2-bridge.js
index c949719..633a1e6 100644
--- a/src/v2-bridge.js
+++ b/src/v2-bridge.js
@@ -100,7 +100,9 @@ function normalizeDirectory(value) {
   let end = directory.length
   while (end > 0 && (directory[end - 1] === "/" || directory[end - 1] === "\\")) end--
   const trimmed = directory.slice(0, end)
-  return process.platform === "win32" ? trimmed.toLowerCase() : trimmed
+  // Windows accepts either separator, so one location can arrive spelled both
+  // ways. Unify them so reloads retire the previous same-location instance.
+  return process.platform === "win32" ? trimmed.replaceAll("/", "\\").toLowerCase() : trimmed
 }
 
 function sessionIDOf(input) {
@@ -672,16 +674,58 @@ export function normalizeCommandName(value) {
  * @param {(context: {client: unknown, directory?: string}, options: object) => Promise<object>} goalPluginFactory
  */
 export function createV2Setup(goalPluginFactory) {
+  // Everything setup starts is tracked here so a setup that fails partway can
+  // still be torn down. Without that, a rejected setup leaked its event
+  // subscription, timers, hook registrations and persistence lease on every
+  // host location boot (issue #81).
+  const disposeInstance = (instance) => instance.disposePromise ||= (async () => {
+    const { host, timers, controller, registrations } = instance
+    host.disposed = true
+    for (const timer of timers) clearTimeout(timer)
+    timers.clear()
+    controller.abort()
+    for (const registration of [...registrations].reverse()) {
+      try {
+        await registration?.dispose?.()
+      } catch {
+        // Disposal is best-effort; registrations are also disposed on unload.
+      }
+    }
+    try {
+      await instance.hooks?.dispose?.()
+    } catch (error) {
+      logError("OpenCode 2 dispose hook failed", error?.stack || error?.message || error)
+    }
+  })()
+
   const setupInstance = async function setup(ctx) {
-    const host = createHostState()
+    const instance = {
+      host: createHostState(),
+      registrations: [],
+      timers: new Set(),
+      controller: new AbortController(),
+      hooks: null,
+      disposePromise: null,
+    }
+    try {
+      await wireInstance(ctx, instance)
+    } catch (error) {
+      await disposeInstance(instance)
+      throw error
+    }
+    return () => disposeInstance(instance)
+  }
+
+  async function wireInstance(ctx, instance) {
+    const { host, registrations, timers, controller } = instance
     const directory = ctx?.location?.directory || process.cwd()
     // V2's session API only speaks the flat argument shape; the compatibility
     // adapter probes the legacy generated-client shape otherwise.
     const options = { ...(isPlainObject(ctx?.options) ? ctx.options : {}), sdkShape: "flat" }
     const client = createV2Client(ctx, host, options)
     const hooks = await goalPluginFactory({ client, directory }, options)
+    instance.hooks = hooks
 
-    const registrations = []
     const track = async (registration) => {
       registrations.push(registration)
       return registration
@@ -958,7 +1002,6 @@ export function createV2Setup(goalPluginFactory) {
 
     /* ---------------- event stream ---------------- */
 
-    const controller = new AbortController()
     const consumeEvents = async () => {
       try {
         for await (const event of ctx.event.subscribe({ signal: controller.signal })) {
@@ -992,7 +1035,6 @@ export function createV2Setup(goalPluginFactory) {
 
     /* ---------------- deferred host-activation work ---------------- */
 
-    const timers = new Set()
     const later = (fn, delay) => {
       const timer = setTimeout(() => {
         timers.delete(timer)
@@ -1080,25 +1122,6 @@ export function createV2Setup(goalPluginFactory) {
 
     /* ---------------- cleanup ---------------- */
 
-    let disposePromise
-    return () => disposePromise ||= (async () => {
-      host.disposed = true
-      for (const timer of timers) clearTimeout(timer)
-      timers.clear()
-      controller.abort()
-      for (const registration of [...registrations].reverse()) {
-        try {
-          await registration.dispose()
-        } catch {
-          // Disposal is best-effort; registrations are also disposed on unload.
-        }
-      }
-      try {
-        await hooks.dispose()
-      } catch (error) {
-        hookError("dispose", error)
-      }
-    })()
   }
   return async function setup(ctx) {
     // Host reloads can omit cleanup. Retire the old same-location instance
diff --git a/test/persistence-lease.test.js b/test/persistence-lease.test.js
index caef8b7..1e2dc97 100644
--- a/test/persistence-lease.test.js
+++ b/test/persistence-lease.test.js
@@ -135,6 +135,20 @@ async function acquireVersion1Lease(
   throw new Error("version-1 lease exhausted")
 }
 
+test("the host's own pid is alive without being signalled", () => {
+  const original = process.kill
+  const signalled = []
+  process.kill = (pid, signal) => { signalled.push([pid, signal]); return true }
+  try {
+    assert.equal(persistenceLeaseInternals.processIsAlive(process.pid), true)
+    assert.deepEqual(signalled, [], "signal 0 may terminate the caller on Windows runtimes (#81)")
+    persistenceLeaseInternals.processIsAlive(process.pid + 1)
+    assert.equal(signalled.length, 1, "other pids still get the liveness probe")
+  } finally {
+    process.kill = original
+  }
+})
+
 test("persistence lease rejects a concurrent owner and releases by token", async () => {
   const dir = await mkdtemp(join(tmpdir(), "goal-lease-"))
   const state = join(dir, "state.json")
diff --git a/test/v2-bridge.test.js b/test/v2-bridge.test.js
index e9f18fa..561afb1 100644
--- a/test/v2-bridge.test.js
+++ b/test/v2-bridge.test.js
@@ -646,6 +646,35 @@ test("same-location setup retires the previous instance instead of stealing a li
   assert.equal(disposals, 2)
 })
 
+test("a setup that fails partway disposes everything it already started", async () => {
+  let disposals = 0
+  const factory = async () => ({ config: async () => {}, dispose: async () => { disposals++ }, "command.execute.before": async () => {} })
+  const { ctx, registrations } = createFakeCtx({ pluginOptions: { registerAgents: false } })
+  ctx.session.hook = async () => ({ dispose: async () => { registrations.push("session:prompt") } })
+  ctx.command.transform = async () => { throw new Error("host rejected command") }
+  await assert.rejects(createV2Setup(factory)(ctx), /host rejected command/)
+  assert.equal(disposals, 1, "the core (and its persistence lease) is released")
+  assert.ok(registrations.includes("session:prompt"), "hook registrations are released")
+
+  // The failed attempt must not block the next boot of the same location.
+  const retry = createFakeCtx({ pluginOptions: { registerAgents: false } }).ctx
+  const cleanup = await createV2Setup(factory)(retry)
+  assert.equal(disposals, 1)
+  await cleanup()
+  assert.equal(disposals, 2)
+})
+
+test("on Windows, either separator spelling names the same location", () => {
+  const original = Object.getOwnPropertyDescriptor(process, "platform")
+  Object.defineProperty(process, "platform", { ...original, value: "win32" })
+  try {
+    const event = { type: "session.execution.succeeded", data: { sessionID: "s1" }, location: { directory: "C:/Proj/App/" } }
+    assert.equal(eventBelongsToLocation(event, "c:\\proj\\app"), true)
+  } finally {
+    Object.defineProperty(process, "platform", original)
+  }
+})
+
 test("setup registers every V2 surface the goal workflow needs", async () => {
   const { ctx, registered } = createFakeCtx()
   const cleanup = await createV2Setup(GoalPlugin)(ctx)