diff --git a/src/main/gitlab/client-mr.test.ts b/src/main/gitlab/client-mr.test.ts
index 4ec609ded..21747de6a 100644
--- a/src/main/gitlab/client-mr.test.ts
+++ b/src/main/gitlab/client-mr.test.ts
@@ -555,6 +555,20 @@ describe('gitlab client — MR operations', () => {
       }
     })
 
+    it('appends an encoded &search= param when a query is supplied', async () => {
+      glabApiWithHeadersMock.mockResolvedValueOnce({ body: '[]', headers: {} })
+      await listMergeRequests('/repo', 'opened', 1, 20, undefined, 'fix login')
+      const callArgs = glabApiWithHeadersMock.mock.calls[0][0] as string[]
+      expect(callArgs[0]).toContain('&search=fix%20login')
+    })
+
+    it('omits &search= for an empty or whitespace-only query', async () => {
+      glabApiWithHeadersMock.mockResolvedValueOnce({ body: '[]', headers: {} })
+      await listMergeRequests('/repo', 'opened', 1, 20, undefined, '   ')
+      const callArgs = glabApiWithHeadersMock.mock.calls[0][0] as string[]
+      expect(callArgs[0]).not.toContain('search=')
+    })
+
     it('flags fork MRs as cross-repository', async () => {
       glabApiWithHeadersMock.mockResolvedValueOnce({
         body: JSON.stringify([
@@ -618,6 +632,32 @@ describe('gitlab client — MR operations', () => {
       )
     })
 
+    it('threads --search into the cwd fallback when a query is supplied', async () => {
+      resolveIssueSourceMock.mockResolvedValueOnce({
+        source: null,
+        fellBack: false
+      })
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '[]' })
+      await listMergeRequests('/repo', 'opened', 1, 20, undefined, 'fix login')
+      expect(glabApiWithHeadersMock).not.toHaveBeenCalled()
+      const callArgs = glabExecFileAsyncMock.mock.calls[0][0] as string[]
+      // Why (#6263): the cwd-inferred fallback must honor the typed query too.
+      const searchIdx = callArgs.indexOf('--search')
+      expect(searchIdx).toBeGreaterThanOrEqual(0)
+      expect(callArgs[searchIdx + 1]).toBe('fix login')
+    })
+
+    it('omits --search from the cwd fallback for a whitespace-only query', async () => {
+      resolveIssueSourceMock.mockResolvedValueOnce({
+        source: null,
+        fellBack: false
+      })
+      glabExecFileAsyncMock.mockResolvedValueOnce({ stdout: '[]' })
+      await listMergeRequests('/repo', 'opened', 1, 20, undefined, '   ')
+      const callArgs = glabExecFileAsyncMock.mock.calls[0][0] as string[]
+      expect(callArgs).not.toContain('--search')
+    })
+
     it('classifies fallback errors into the result envelope', async () => {
       resolveIssueSourceMock.mockResolvedValueOnce({
         source: null,
diff --git a/src/main/gitlab/client.ts b/src/main/gitlab/client.ts
index 11ce0fe67..b5a1569fa 100644
--- a/src/main/gitlab/client.ts
+++ b/src/main/gitlab/client.ts
@@ -433,6 +433,10 @@ export async function listMergeRequests(
     // (e.g. a fresh self-hosted instance), but glab itself can still
     // resolve it from the local git config.
     const stateFlag = mrListStateFlags(state)
+    // Why: the cwd-inferred fallback must honor the same search the API path
+    // does, otherwise typing a query against a self-hosted / unresolved-projectRef
+    // repo silently returns the unfiltered list (the original #6263 symptom).
+    const searchFlag = query?.trim() ? ['--search', query.trim()] : []
     await acquire()
     try {
       const { stdout } = await glabExecFileAsync(
@@ -449,7 +453,8 @@ export async function listMergeRequests(
           'updated_at',
           '--sort',
           'desc',
-          ...stateFlag
+          ...stateFlag,
+          ...searchFlag
         ],
         glabRepoExecOptions(repoPath, connectionId, localGitOptions)
       )
diff --git a/src/main/gitlab/gitlab-preload-args.ts b/src/main/gitlab/gitlab-preload-args.ts
index 5ce88408c..be59907b4 100644
--- a/src/main/gitlab/gitlab-preload-args.ts
+++ b/src/main/gitlab/gitlab-preload-args.ts
@@ -21,6 +21,23 @@ export function normalizeGitLabIssueListState(value: unknown): GitLabIssueListSt
   return value === 'closed' || value === 'all' ? value : 'opened'
 }
 
+// Why: cap the free-text MR search at the same byte budget the renderer
+// enforces (SMART_WORKSPACE_SOURCE_QUERY_MAX_BYTES) so the RPC/SSH path —
+// which can be driven by callers other than the desktop input — can't push
+// an unbounded string into the glab `&search=` query.
+const GITLAB_SEARCH_QUERY_MAX_BYTES = 2048
+
+export function normalizeGitLabSearchQuery(value: unknown): string | undefined {
+  if (typeof value !== 'string') {
+    return undefined
+  }
+  const trimmed = value.trim()
+  if (!trimmed) {
+    return undefined
+  }
+  return Buffer.byteLength(trimmed, 'utf8') > GITLAB_SEARCH_QUERY_MAX_BYTES ? undefined : trimmed
+}
+
 export function normalizeGitLabIssueAssignee(value: unknown): '@me' | undefined {
   // Why: the renderer only exposes "Assigned to me"; accepting arbitrary
   // values would turn preload/RPC boundaries into a generic glab flag surface.
diff --git a/src/main/ipc/gitlab.test.ts b/src/main/ipc/gitlab.test.ts
index 6344fab3d..7002f31d8 100644
--- a/src/main/ipc/gitlab.test.ts
+++ b/src/main/ipc/gitlab.test.ts
@@ -213,6 +213,68 @@ describe('GitLab IPC handlers', () => {
     )
   })
 
+  it('forwards the typed search query into listMRs and listWorkItems', async () => {
+    listMergeRequestsMock.mockResolvedValueOnce({ items: [] })
+    listWorkItemsMock.mockResolvedValueOnce({ items: [] })
+    registerGitLabHandlers(storeWithRepos([repo()]) as Store)
+
+    await ipcHandlers.get('gitlab:listMRs')?.(null, {
+      repoPath: '/local/orca',
+      state: 'opened',
+      page: 1,
+      perPage: 20,
+      query: '  fix login  '
+    })
+    await ipcHandlers.get('gitlab:listWorkItems')?.(null, {
+      repoPath: '/local/orca',
+      state: 'opened',
+      page: 1,
+      perPage: 20,
+      query: 'fix login'
+    })
+
+    // Why (#6263): the trimmed query must land in the 6th positional arg —
+    // previously the slot was hardcoded to `undefined`, so search never worked.
+    expect(listMergeRequestsMock).toHaveBeenCalledWith(
+      '/local/orca',
+      'opened',
+      1,
+      20,
+      undefined,
+      'fix login',
+      null
+    )
+    expect(listWorkItemsMock).toHaveBeenCalledWith(
+      '/local/orca',
+      'opened',
+      1,
+      20,
+      undefined,
+      'fix login',
+      null
+    )
+  })
+
+  it('drops blank or whitespace-only search queries to undefined', async () => {
+    listMergeRequestsMock.mockResolvedValueOnce({ items: [] })
+    registerGitLabHandlers(storeWithRepos([repo()]) as Store)
+
+    await ipcHandlers.get('gitlab:listMRs')?.(null, {
+      repoPath: '/local/orca',
+      query: '   '
+    })
+
+    expect(listMergeRequestsMock).toHaveBeenCalledWith(
+      '/local/orca',
+      'opened',
+      1,
+      20,
+      undefined,
+      undefined,
+      null
+    )
+  })
+
   it('rejects source context for a different host', async () => {
     registerGitLabHandlers(
       storeWithRepos([repo({ id: 'repo-local', path: '/local/orca' })]) as Store
diff --git a/src/main/ipc/gitlab.ts b/src/main/ipc/gitlab.ts
index 241060e0a..9e69c93aa 100644
--- a/src/main/ipc/gitlab.ts
+++ b/src/main/ipc/gitlab.ts
@@ -17,7 +17,8 @@ import {
   normalizeGitLabIssueAssignee,
   normalizeGitLabIssueListState,
   normalizeGitLabMRListState,
-  normalizeGitLabPositiveInteger
+  normalizeGitLabPositiveInteger,
+  normalizeGitLabSearchQuery
 } from '../gitlab/gitlab-preload-args'
 import { recordGitLabProjectRecent } from '../gitlab/gitlab-project-recents'
 import {
@@ -165,6 +166,7 @@ export function registerGitLabHandlers(store: Store): void {
         state?: 'opened' | 'merged' | 'closed' | 'all'
         page?: number
         perPage?: number
+        query?: string
       }
     ) => {
       const repo = assertRegisteredRepo(args, store)
@@ -177,7 +179,7 @@ export function registerGitLabHandlers(store: Store): void {
         page,
         perPage,
         repo.issueSourcePreference,
-        undefined,
+        normalizeGitLabSearchQuery(args.query),
         repoConnectionId(repo),
         ...localGitOptionArgs(store, repo)
       )
@@ -326,6 +328,7 @@ export function registerGitLabHandlers(store: Store): void {
         state?: 'opened' | 'merged' | 'closed' | 'all'
         page?: number
         perPage?: number
+        query?: string
       }
     ) => {
       const repo = assertRegisteredRepo(args, store)
@@ -335,7 +338,7 @@ export function registerGitLabHandlers(store: Store): void {
         normalizeGitLabPositiveInteger(args.page, 1, 10_000),
         normalizeGitLabPositiveInteger(args.perPage, 20, 100),
         repo.issueSourcePreference,
-        undefined,
+        normalizeGitLabSearchQuery(args.query),
         repoConnectionId(repo),
         ...localGitOptionArgs(store, repo)
       )
diff --git a/src/main/runtime/orca-runtime.test.ts b/src/main/runtime/orca-runtime.test.ts
index 0c11b6685..4ae08c2cf 100644
--- a/src/main/runtime/orca-runtime.test.ts
+++ b/src/main/runtime/orca-runtime.test.ts
@@ -21329,6 +21329,66 @@ describe('OrcaRuntimeService', () => {
     )
   })
 
+  it('keeps the MR source base when the optional compare-base fetch fails', async () => {
+    // Why (#6263): a merged MR may have had its target ref deleted. A failed
+    // compare-base fetch must not abort and silently drop the worktree onto
+    // the repo default branch — keep the verified source base, drop compareBaseRef.
+    const localRepo = {
+      id: TEST_REPO_ID,
+      path: TEST_REPO_PATH,
+      displayName: 'repo',
+      badgeColor: 'blue',
+      addedAt: 1,
+      issueSourcePreference: 'origin' as const
+    }
+    const runtimeStore = {
+      ...store,
+      getRepos: () => [localRepo],
+      getRepo: (id: string) => (id === localRepo.id ? localRepo : undefined)
+    }
+    getGitLabProjectRefForRemoteMock.mockResolvedValue({
+      host: 'gitlab.example',
+      path: 'group/repo'
+    })
+    const runtime = new OrcaRuntimeService(runtimeStore as never)
+    const gitSpy = vi.spyOn(gitRunner, 'gitExecFileAsync').mockImplementation(async (args) => {
+      if (
+        args[0] === 'fetch' &&
+        args[2] === '+refs/heads/feature/fix:refs/remotes/origin/feature/fix'
+      ) {
+        return { stdout: '', stderr: '' }
+      }
+      if (args[0] === 'fetch' && args[2] === '+refs/heads/main:refs/remotes/origin/main') {
+        // Target branch was deleted on the remote (merged MR).
+        throw new Error("couldn't find remote ref refs/heads/main")
+      }
+      if (args[0] === 'rev-parse' && args[1] === '--verify' && args[2] === 'origin/feature/fix') {
+        return { stdout: 'same-repo-mr-sha\n', stderr: '' }
+      }
+      throw new Error(`unexpected git call: ${args.join(' ')}`)
+    })
+    gitSpy.mockClear()
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    try {
+      const result = await runtime.resolveManagedMrBase({
+        repoSelector: 'id:repo-1',
+        mrIid: 79,
+        sourceBranch: 'feature/fix',
+        targetBranch: 'main'
+      })
+
+      expect(result).toEqual({
+        baseBranch: 'origin/feature/fix',
+        pushTarget: { remoteName: 'origin', branchName: 'feature/fix' }
+      })
+      expect(result).not.toHaveProperty('compareBaseRef')
+      expect(result).not.toHaveProperty('error')
+    } finally {
+      warnSpy.mockRestore()
+      gitSpy.mockRestore()
+    }
+  })
+
   it('creates the first terminal by id when duplicate repo entries expose the same path', async () => {
     const runtime = new OrcaRuntimeService(store)
     const spawn = vi.fn().mockResolvedValue({ id: 'pty-duplicate-path' })
diff --git a/src/main/runtime/orca-runtime.ts b/src/main/runtime/orca-runtime.ts
index c5fc22bf8..8ae5d68a7 100644
--- a/src/main/runtime/orca-runtime.ts
+++ b/src/main/runtime/orca-runtime.ts
@@ -14120,17 +14120,27 @@ export class OrcaRuntimeService {
         ? sshGitProvider.fetchRemoteTrackingRef(repo.path, remote, branch, ref)
         : gitExec(['fetch', remote, `+refs/heads/${branch}:${ref}`]))
     }
-    const fetchTargetBranch = async (): Promise<{ error: string } | null> => {
+    // Why: the target/compare branch is optional (it only powers the diff
+    // base). A merged MR may have had its target ref deleted, so a fetch
+    // failure must NOT abort the whole resolution — that would discard the
+    // already-verified source-branch base and silently fall back to the repo
+    // default branch. Degrade gracefully by dropping compareBaseRef instead.
+    const fetchCompareBaseRef = async (): Promise<boolean> => {
       if (!targetBranch || !compareBaseRef) {
-        return null
+        return false
       }
       try {
         await fetchRemoteTrackingRef(targetBranch, compareBaseRef)
+        return true
       } catch (error) {
-        const message = error instanceof Error ? error.message : String(error)
-        return { error: `Failed to fetch ${remote}/${targetBranch}: ${message.split('\n')[0]}` }
+        console.warn('[runtime:resolveManagedMrBase] optional compare-base fetch failed', {
+          remote,
+          targetBranch,
+          mrIid: args.mrIid,
+          error: error instanceof Error ? error.message.split('\n')[0] : String(error)
+        })
+        return false
       }
-      return null
     }
 
     if (isCrossRepository) {
@@ -14155,11 +14165,8 @@ export class OrcaRuntimeService {
       if (!sha) {
         return { error: `Empty SHA resolving fork MR !${args.mrIid} head.` }
       }
-      const targetFetchError = await fetchTargetBranch()
-      if (targetFetchError) {
-        return targetFetchError
-      }
-      return { baseBranch: sha, ...(compareBaseRef ? { compareBaseRef } : {}) }
+      const compareBaseFetched = await fetchCompareBaseRef()
+      return { baseBranch: sha, ...(compareBaseFetched ? { compareBaseRef } : {}) }
     }
 
     try {
@@ -14175,13 +14182,10 @@ export class OrcaRuntimeService {
     } catch {
       return { error: `Remote ref ${remoteRef} does not exist after fetch.` }
     }
-    const targetFetchError = await fetchTargetBranch()
-    if (targetFetchError) {
-      return targetFetchError
-    }
+    const compareBaseFetched = await fetchCompareBaseRef()
     return {
       baseBranch: remoteRef,
-      ...(compareBaseRef ? { compareBaseRef } : {}),
+      ...(compareBaseFetched ? { compareBaseRef } : {}),
       pushTarget: { remoteName: remote, branchName: sourceBranch }
     }
   }
diff --git a/src/preload/api-types.ts b/src/preload/api-types.ts
index 00514423f..a25297106 100644
--- a/src/preload/api-types.ts
+++ b/src/preload/api-types.ts
@@ -1507,6 +1507,7 @@ export type PreloadApi = {
         state?: MRListState
         page?: number
         perPage?: number
+        query?: string
       }
     ) => Promise<ListMergeRequestsResult>
     /** Combined MR + issue list filtered by state. Issues are skipped
@@ -1516,6 +1517,7 @@ export type PreloadApi = {
         state?: MRListState
         page?: number
         perPage?: number
+        query?: string
       }
     ) => Promise<ListMergeRequestsResult>
     issue: (args: GitLabRepoSelectorArgs & { number: number }) => Promise<GitLabIssueInfo | null>
diff --git a/src/preload/gitlab.ts b/src/preload/gitlab.ts
index bc14907d7..28c6f763e 100644
--- a/src/preload/gitlab.ts
+++ b/src/preload/gitlab.ts
@@ -35,6 +35,7 @@ export const glApi = {
       state?: 'opened' | 'merged' | 'closed' | 'all'
       page?: number
       perPage?: number
+      query?: string
     }
   ): Promise<unknown> => ipcRenderer.invoke('gitlab:listMRs', args),
 
@@ -43,6 +44,7 @@ export const glApi = {
       state?: 'opened' | 'merged' | 'closed' | 'all'
       page?: number
       perPage?: number
+      query?: string
     }
   ): Promise<unknown> => ipcRenderer.invoke('gitlab:listWorkItems', args),
 
diff --git a/src/renderer/src/components/new-workspace/SmartWorkspaceNameField.tsx b/src/renderer/src/components/new-workspace/SmartWorkspaceNameField.tsx
index 425dd8d03..f508faebd 100644
--- a/src/renderer/src/components/new-workspace/SmartWorkspaceNameField.tsx
+++ b/src/renderer/src/components/new-workspace/SmartWorkspaceNameField.tsx
@@ -976,6 +976,10 @@ export default function SmartWorkspaceNameField({
     }
     let stale = false
     setGitlabLoading(true)
+    // Why: thread the typed query through so the GitLab API filters MRs by
+    // name/number (mirrors the GitHub effect). shouldQueryGitlab already
+    // gates on sourceQueryWithinLimit, so an oversized query never reaches here.
+    const trimmedQuery = debouncedQuery.trim() || undefined
     void Promise.all(
       repoBackedSearchTargets.map((target) =>
         listGitLabMRsForSource({
@@ -984,7 +988,8 @@ export default function SmartWorkspaceNameField({
           sourceContext: target.gitlabSourceContext,
           state: mrStateFilter,
           page: 1,
-          perPage: RESULT_LIMIT
+          perPage: RESULT_LIMIT,
+          query: trimmedQuery
         }).catch(() => ({ items: [], hasMore: false }))
       )
     )
@@ -1013,6 +1018,7 @@ export default function SmartWorkspaceNameField({
       stale = true
     }
   }, [
+    debouncedQuery,
     disabled,
     mode,
     mrStateFilter,
diff --git a/src/renderer/src/hooks/useComposerState-host-context-boundaries.test.ts b/src/renderer/src/hooks/useComposerState-host-context-boundaries.test.ts
index 5a8bdf55a..7ad739b74 100644
--- a/src/renderer/src/hooks/useComposerState-host-context-boundaries.test.ts
+++ b/src/renderer/src/hooks/useComposerState-host-context-boundaries.test.ts
@@ -45,6 +45,11 @@ describe('useComposerState host-context boundaries', () => {
     expect(section).toContain('worktree.resolveMrBase')
     expect(section).toContain('repo: runRepo.id')
     expect(section).not.toContain('repoId: repoForItem.id')
+    // Why (#6263): an unresolved MR base must surface a toast and clear stale
+    // state instead of silently dropping the worktree onto origin/master.
+    expect(section).toContain('toast.error(result.error)')
+    expect(section).toContain("'Failed to resolve MR base.'")
+    expect(section).toMatch(/\.catch\(\(error: unknown\) =>/)
   })
 
   it('does not use local SSH gates for runtime-owned folder targets', () => {
diff --git a/src/renderer/src/hooks/useComposerState.ts b/src/renderer/src/hooks/useComposerState.ts
index b0d5511d1..7de0f11ad 100644
--- a/src/renderer/src/hooks/useComposerState.ts
+++ b/src/renderer/src/hooks/useComposerState.ts
@@ -2702,12 +2702,35 @@ export function useComposerState(options: UseComposerStateOptions): UseComposerS
               },
               { timeoutMs: 30_000 }
             )
-      void resolveMrBase.then((result) => {
-        if ('error' in result) {
-          return
-        }
-        handleBaseBranchMrSelect(result.baseBranch, item, result.pushTarget, result.compareBaseRef)
-      })
+      void resolveMrBase
+        .then((result) => {
+          if ('error' in result) {
+            // Why: without surfacing the failure the worktree silently falls
+            // back to the repo default branch (origin/master), so clear stale
+            // base state and tell the user — mirrors the GitHub PR path.
+            setBaseBranch(undefined)
+            setCompareBaseRef(undefined)
+            setPushTarget(undefined)
+            toast.error(result.error)
+            return
+          }
+          handleBaseBranchMrSelect(
+            result.baseBranch,
+            item,
+            result.pushTarget,
+            result.compareBaseRef
+          )
+        })
+        .catch((error: unknown) => {
+          setBaseBranch(undefined)
+          setCompareBaseRef(undefined)
+          setPushTarget(undefined)
+          toast.error(
+            error instanceof Error
+              ? error.message
+              : translate('auto.hooks.useComposerState.5f3d2c8a1b', 'Failed to resolve MR base.')
+          )
+        })
     },
     [
       applyLinkedGitLabWorkItem,
diff --git a/src/renderer/src/i18n/locales/en.json b/src/renderer/src/i18n/locales/en.json
index 559023da3..5a4f04e6e 100644
--- a/src/renderer/src/i18n/locales/en.json
+++ b/src/renderer/src/i18n/locales/en.json
@@ -543,7 +543,8 @@
         "chooseOrAddProjectBeforeWorkspace": "Choose or add a project before creating a workspace.",
         "folderWorkspaceCreateFailedTitle": "Folder workspace creation failed",
         "folderWorkspaceCreateFailedMessage": "The folder workspace could not be created. Check the error details above, then try again.",
-        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior."
+        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior.",
+        "5f3d2c8a1b": "Failed to resolve MR base."
       },
       "useGlobalFileDrop": {
         "38c9f034ff": "Failed to upload dropped files.",
diff --git a/src/renderer/src/i18n/locales/es.json b/src/renderer/src/i18n/locales/es.json
index 0c85b5bde..0b5d62fa8 100644
--- a/src/renderer/src/i18n/locales/es.json
+++ b/src/renderer/src/i18n/locales/es.json
@@ -543,7 +543,8 @@
         "chooseOrAddProjectBeforeWorkspace": "Elige o agrega un proyecto antes de crear un espacio de trabajo.",
         "folderWorkspaceCreateFailedTitle": "No se pudo crear el espacio de trabajo de carpeta",
         "folderWorkspaceCreateFailedMessage": "No se pudo crear el espacio de trabajo de carpeta. Revisa los detalles del error de arriba e inténtalo de nuevo.",
-        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior."
+        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior.",
+        "5f3d2c8a1b": "Failed to resolve MR base."
       },
       "useGlobalFileDrop": {
         "38c9f034ff": "No se pudieron cargar los archivos eliminados.",
diff --git a/src/renderer/src/i18n/locales/ja.json b/src/renderer/src/i18n/locales/ja.json
index a801f65bd..b6de9e836 100644
--- a/src/renderer/src/i18n/locales/ja.json
+++ b/src/renderer/src/i18n/locales/ja.json
@@ -543,7 +543,8 @@
         "chooseOrAddProjectBeforeWorkspace": "ワークスペースを作成する前に、プロジェクトを選択または追加。",
         "folderWorkspaceCreateFailedTitle": "フォルダーワークスペースを作成できませんでした",
         "folderWorkspaceCreateFailedMessage": "フォルダーワークスペースを作成できませんでした。上のエラー詳細を確認して、もう一度お試しください。",
-        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior."
+        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior.",
+        "5f3d2c8a1b": "Failed to resolve MR base."
       },
       "useGlobalFileDrop": {
         "38c9f034ff": "ドロップされたファイルのアップロードに失敗しました。",
diff --git a/src/renderer/src/i18n/locales/ko.json b/src/renderer/src/i18n/locales/ko.json
index 615cb7c3f..888eb9e19 100644
--- a/src/renderer/src/i18n/locales/ko.json
+++ b/src/renderer/src/i18n/locales/ko.json
@@ -543,7 +543,8 @@
         "chooseOrAddProjectBeforeWorkspace": "워크스페이스를 만들기 전에 프로젝트를 선택하거나 추가하세요.",
         "folderWorkspaceCreateFailedTitle": "폴더 워크스페이스를 만들지 못했습니다",
         "folderWorkspaceCreateFailedMessage": "폴더 워크스페이스를 만들 수 없습니다. 위의 오류 세부 정보를 확인한 뒤 다시 시도하세요.",
-        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior."
+        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior.",
+        "5f3d2c8a1b": "Failed to resolve MR base."
       },
       "useGlobalFileDrop": {
         "38c9f034ff": "드롭한 파일을 업로드하지 못했습니다.",
diff --git a/src/renderer/src/i18n/locales/zh.json b/src/renderer/src/i18n/locales/zh.json
index d292efcc1..5f3fa0b1d 100644
--- a/src/renderer/src/i18n/locales/zh.json
+++ b/src/renderer/src/i18n/locales/zh.json
@@ -543,7 +543,8 @@
         "chooseOrAddProjectBeforeWorkspace": "创建工作区前，请选择或添加项目。",
         "folderWorkspaceCreateFailedTitle": "文件夹工作区创建失败",
         "folderWorkspaceCreateFailedMessage": "无法创建文件夹工作区。请查看上方错误详情，然后重试。",
-        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior."
+        "setupAgentStartupPolicySaveFailed": "Failed to save setup startup behavior.",
+        "5f3d2c8a1b": "Failed to resolve MR base."
       },
       "useGlobalFileDrop": {
         "38c9f034ff": "无法上传删除的文件。",
diff --git a/src/renderer/src/lib/gitlab-work-item-source-lookup.test.ts b/src/renderer/src/lib/gitlab-work-item-source-lookup.test.ts
index 64197e684..82d9b8262 100644
--- a/src/renderer/src/lib/gitlab-work-item-source-lookup.test.ts
+++ b/src/renderer/src/lib/gitlab-work-item-source-lookup.test.ts
@@ -94,19 +94,60 @@ describe('GitLab source lookup routing', () => {
         sourceContext: runtimeSourceContext,
         state: 'opened',
         page: 1,
-        perPage: 12
+        perPage: 12,
+        query: 'fix login'
       })
     ).resolves.toMatchObject({ items: [{ repoId: 'renderer-repo', number: 7 }] })
 
+    // Why (#6263): the typed query must reach the runtime RPC so GitLab search
+    // actually filters; previously the field was never threaded through.
     expect(callRuntimeRpc).toHaveBeenCalledWith(
       { kind: 'environment', environmentId: 'env-1' },
       'gitlab.listMRs',
-      { repo: 'runtime-repo', state: 'opened', page: 1, perPage: 12 },
+      { repo: 'runtime-repo', state: 'opened', page: 1, perPage: 12, query: 'fix login' },
       { timeoutMs: 30_000 }
     )
     expect(window.api.gl.listMRs).not.toHaveBeenCalled()
   })
 
+  it('forwards the search query to local GitLab MR lists over Electron IPC', async () => {
+    const localSourceContext: TaskSourceContext = {
+      ...runtimeSourceContext,
+      hostId: 'local',
+      repoId: 'local-repo'
+    }
+    vi.mocked(window.api.gl.listMRs).mockResolvedValue({
+      items: [gitlabItem({ repoId: 'local-returned' })],
+      page: 1,
+      perPage: 12,
+      totalCount: 1,
+      totalPages: 1
+    })
+
+    await expect(
+      listGitLabMRsForSource({
+        repoPath: '/workspace/app',
+        repoId: 'local-repo',
+        sourceContext: localSourceContext,
+        state: 'opened',
+        page: 1,
+        perPage: 12,
+        query: 'fix login'
+      })
+    ).resolves.toMatchObject({ items: [{ repoId: 'local-repo', number: 7 }] })
+
+    expect(window.api.gl.listMRs).toHaveBeenCalledWith({
+      repoPath: '/workspace/app',
+      repoId: 'local-repo',
+      sourceContext: localSourceContext,
+      state: 'opened',
+      page: 1,
+      perPage: 12,
+      query: 'fix login'
+    })
+    expect(callRuntimeRpc).not.toHaveBeenCalled()
+  })
+
   it('keeps local GitLab lookups on Electron IPC with source context', async () => {
     vi.mocked(window.api.gl.workItemByPath).mockResolvedValue(
       gitlabItem({ repoId: 'local-returned' })
diff --git a/src/renderer/src/lib/gitlab-work-item-source-lookup.ts b/src/renderer/src/lib/gitlab-work-item-source-lookup.ts
index a99700d58..911997a82 100644
--- a/src/renderer/src/lib/gitlab-work-item-source-lookup.ts
+++ b/src/renderer/src/lib/gitlab-work-item-source-lookup.ts
@@ -20,6 +20,7 @@ type GitLabMRListLookupArgs = GitLabSourceLookupArgs & {
   state?: 'opened' | 'merged' | 'closed' | 'all'
   page?: number
   perPage?: number
+  query?: string
 }
 
 function runtimeRepoId(args: Pick<GitLabSourceLookupArgs, 'repoId' | 'sourceContext'>): string {
@@ -73,7 +74,8 @@ export async function listGitLabMRsForSource(
             repo: runtimeRepoId(args),
             state: args.state,
             page: args.page,
-            perPage: args.perPage
+            perPage: args.perPage,
+            query: args.query
           },
           { timeoutMs: 30_000 }
         )
@@ -83,7 +85,8 @@ export async function listGitLabMRsForSource(
           sourceContext: args.sourceContext,
           state: args.state,
           page: args.page,
-          perPage: args.perPage
+          perPage: args.perPage,
+          query: args.query
         })) as ListMergeRequestsResult)
   return {
     ...result,