diff --git a/workbuddy-plugin/package.json b/workbuddy-plugin/package.json
index cf067e2..14371d3 100644
--- a/workbuddy-plugin/package.json
+++ b/workbuddy-plugin/package.json
@@ -31,7 +31,7 @@
     "test": "vitest run",
     "check": "npm test && npm run build && node scripts/validate.mjs",
     "pack:release": "npm run check && node scripts/package.mjs",
-    "smoke:packed": "node scripts/test-preflight.mjs && node scripts/test-install.mjs && node scripts/smoke-packed.mjs && node scripts/test-release-installer.mjs",
+    "smoke:packed": "node scripts/test-preflight.mjs && node scripts/test-install.mjs && node scripts/test-mcp-conflict.mjs && node scripts/smoke-packed.mjs && node scripts/test-release-installer.mjs",
     "test:browser": "npm run build && node scripts/test-wall-browser.mjs",
     "test:native": "npm run build && node scripts/test-native.mjs",
     "test:host": "npm run build && node scripts/test-workbuddy-host.mjs"
diff --git a/workbuddy-plugin/scripts/install-local.mjs b/workbuddy-plugin/scripts/install-local.mjs
index dad2132..182bf08 100644
--- a/workbuddy-plugin/scripts/install-local.mjs
+++ b/workbuddy-plugin/scripts/install-local.mjs
@@ -50,8 +50,18 @@ for (const path of targets) await assertOwnedPath(path)
 const existingMcp = JSON.parse(original[0] ?? '{}').mcpServers?.opengui
 if (existingMcp) {
   const knownEntrypoints = [packageDir, previous.packageDir].filter(Boolean).map(path => join(path, 'lib', 'mcp.js'))
-  assert(Array.isArray(existingMcp.args) && existingMcp.args.length === 1 && knownEntrypoints.includes(existingMcp.args[0]),
-    'MCP_CONFLICT: an unrecognized opengui server already exists; preserve it and resolve the conflict explicitly')
+  const ownedStdio = (!existingMcp.type || existingMcp.type === 'stdio') && Array.isArray(existingMcp.args)
+    && existingMcp.args.length === 1 && knownEntrypoints.includes(existingMcp.args[0])
+  // Native installations record the exact server, including its authorization.
+  // A matching URL alone cannot establish ownership of a third-party entry.
+  const ownedHttp = previous.configRoot === root && previous.transport === 'http' && existingMcp.type === 'http'
+    && previous.nativeServerSha256 === createHash('sha256').update(JSON.stringify(existingMcp)).digest('hex')
+  assert(ownedStdio || ownedHttp,
+    `MCP_CONFLICT: unrecognized or edited opengui server in ${targets[0]}. No configuration files changed.\n`
+    + `Back up and inspect the configuration before retrying:\ncp ${quote(targets[0])} ${quote(`${targets[0]}.before-opengui-conflict-${Date.now()}`)}\n`
+    + `\${EDITOR:-vi} ${quote(targets[0])}\n`
+    + 'To keep the existing server, rename its mcpServers key from opengui to an unused name (for example opengui-existing); '
+    + 'or explicitly remove only that entry if it is no longer needed. Save, then rerun the installation command.')
 }
 const values = [
   JSON.stringify(mergeMcpConfig(JSON.parse(original[0] ?? '{}'), node, join(packageDir, 'lib', 'mcp.js')), null, 2) + '\n',
diff --git a/workbuddy-plugin/scripts/test-mcp-conflict.mjs b/workbuddy-plugin/scripts/test-mcp-conflict.mjs
new file mode 100644
index 0000000..6e2ec84
--- /dev/null
+++ b/workbuddy-plugin/scripts/test-mcp-conflict.mjs
@@ -0,0 +1,63 @@
+import assert from 'node:assert/strict'
+import { createHash } from 'node:crypto'
+import { execFileSync, spawnSync } from 'node:child_process'
+import { mkdtemp, mkdir, readFile, realpath, rm, writeFile } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+const temporary = await realpath(await mkdtemp(join(tmpdir(), 'opengui-conflict-')))
+const script = fileURLToPath(new URL('./install-local.mjs', import.meta.url))
+const hash = value => createHash('sha256').update(value).digest('hex')
+try {
+  const root = join(temporary, "host with spaces and 'quote")
+  const state = join(root, 'opengui')
+  const pkg = join(state, 'packages/new/node_modules/opengui-mcp')
+  await mkdir(join(pkg, 'lib'), { recursive: true })
+  await writeFile(join(pkg, 'package.json'), JSON.stringify({ name: 'opengui-mcp', version: '0.4.0' }))
+  await writeFile(join(pkg, 'lib/host-hook.js'), '// Fixture only\n')
+  await writeFile(join(pkg, 'lib/opengui-SKILL.md'), 'fixture skill\n')
+  const receiptPath = join(state, `local-install-${hash(root).slice(0, 16)}.json`)
+  const http = { type: 'http', timeout: 120000, disabled: false, url: 'http://127.0.0.1:61785/mcp', headers: { Authorization: 'Bearer fixture-only' } }
+  const receipt = { configRoot: root, packageDir: join(state, 'packages/old/node_modules/opengui-mcp'), transport: 'http', nativeServerSha256: hash(JSON.stringify(http)), hookCommands: [] }
+  const args = [script, '--config-root', root, '--state-root', state, '--package-dir', pkg]
+  const seed = async (server, previous = receipt) => {
+    await writeFile(join(root, 'mcp.json'), JSON.stringify({ mcpServers: { other: { command: 'retained' }, opengui: server } }))
+    await writeFile(join(root, 'settings.json'), '{"user":"retained"}\n')
+    await mkdir(join(root, 'skills/opengui'), { recursive: true })
+    await writeFile(join(root, 'skills/opengui/SKILL.md'), 'old skill\n')
+    await writeFile(receiptPath, JSON.stringify(previous))
+  }
+  await seed(http)
+  const installed = JSON.parse(execFileSync(process.execPath, args, { encoding: 'utf8', stdio: 'pipe' }))
+  const migrated = JSON.parse(await readFile(join(root, 'mcp.json'), 'utf8'))
+  assert.equal(installed.status, 'CONFIG_WRITTEN')
+  assert.equal(migrated.mcpServers.opengui.type, 'stdio')
+  assert.deepEqual(migrated.mcpServers.opengui.args, [join(pkg, 'lib/mcp.js')])
+  assert.equal(migrated.mcpServers.opengui.url, undefined)
+  assert.equal(migrated.mcpServers.opengui.headers, undefined)
+  assert.equal(migrated.mcpServers.other.command, 'retained')
+  assert.equal(JSON.parse(execFileSync(process.execPath, args, { encoding: 'utf8', stdio: 'pipe' })).status, 'ALREADY_CONFIGURED')
+  await seed({ type: 'stdio', command: process.execPath, args: [join(receipt.packageDir, 'lib/mcp.js')] }, { ...receipt, transport: 'stdio' })
+  execFileSync(process.execPath, args, { stdio: 'pipe' })
+  for (const [server, previous] of [
+    [{ command: 'third-party', args: [] }, {}],
+    [http, {}],
+    [{ ...http, url: 'http://127.0.0.1:61786/mcp' }, receipt],
+    [{ ...http, headers: { Authorization: 'Bearer user-edit' } }, receipt],
+    [http, { ...receipt, configRoot: join(temporary, 'other-host') }],
+    [http, { ...receipt, nativeServerSha256: undefined }],
+  ]) {
+    await seed(server, previous)
+    const paths = [join(root, 'mcp.json'), join(root, 'settings.json'), join(root, 'skills/opengui/SKILL.md'), receiptPath]
+    const before = await Promise.all(paths.map(path => readFile(path, 'utf8')))
+    const result = spawnSync(process.execPath, args, { encoding: 'utf8' })
+    assert.notEqual(result.status, 0)
+    assert.match(result.stderr, /MCP_CONFLICT/)
+    assert.match(result.stderr, /cp /)
+    assert.match(result.stderr, /EDITOR/)
+    assert.match(result.stderr, /rename.*opengui/s)
+    assert.deepEqual(await Promise.all(paths.map(path => readFile(path, 'utf8'))), before)
+  }
+  console.log('PASS: HTTP receipt migration, stdio upgrade, reinstall, and six preserved actionable conflicts')
+} finally { await rm(temporary, { recursive: true, force: true }) }
diff --git a/workbuddy-plugin/src/installation.ts b/workbuddy-plugin/src/installation.ts
index 561f225..d37a9c7 100644
--- a/workbuddy-plugin/src/installation.ts
+++ b/workbuddy-plugin/src/installation.ts
@@ -18,8 +18,9 @@ export function mergeHostHooks(settings: Record<string, unknown>, command: strin
 
 export function mergeMcpConfig(config: Record<string, unknown>, node: string, entrypoint: string): Record<string, unknown> {
   const servers = (config.mcpServers ?? {}) as Record<string, unknown>
+  const { url: _url, headers: _headers, ...retained } = (servers.opengui ?? {}) as Record<string, unknown>
   return { ...config, mcpServers: { ...servers, opengui: {
-    ...((servers.opengui ?? {}) as Record<string, unknown>), type: 'stdio', command: node,
+    ...retained, type: 'stdio', command: node,
     args: [entrypoint], timeout: 120000, disabled: false,
   } } }
 }
diff --git a/workbuddy-plugin/tests/installation.spec.ts b/workbuddy-plugin/tests/installation.spec.ts
index 3acb7a1..2ca8d22 100644
--- a/workbuddy-plugin/tests/installation.spec.ts
+++ b/workbuddy-plugin/tests/installation.spec.ts
@@ -13,6 +13,12 @@ describe('scoped WorkBuddy installation', () => {
     expect(Object.keys(updated.hooks as object).sort()).toEqual([...HOST_HOOK_EVENTS].sort())
     expect(JSON.stringify(updated)).not.toContain('permissionDecision')
   })
+  it('removes HTTP transport fields when migrating an owned server to stdio', () => {
+    const original = { mcpServers: { opengui: { type: 'http', url: 'http://127.0.0.1:61785/mcp', headers: { Authorization: 'Bearer fixture' }, extra: true } } }
+    const updated = mergeMcpConfig(original, '/managed/node', '/immutable/lib/mcp.js')
+    expect(updated.mcpServers).toEqual({ opengui: { extra: true, type: 'stdio', command: '/managed/node', args: ['/immutable/lib/mcp.js'], timeout: 120000, disabled: false } })
+    expect(original.mcpServers.opengui.headers.Authorization).toBe('Bearer fixture')
+  })
   it('changes only the OpenGUI MCP entry and preserves its unrelated settings', () => {
     const original = { extra: true, mcpServers: { other: { command: 'production' }, opengui: { command: 'old', env: { KEEP: 'local' } } } }
     expect(mergeMcpConfig(original, '/managed/node', '/immutable/lib/mcp.js')).toEqual({ extra: true, mcpServers: { other: original.mcpServers.other,