diff --git a/Sources/TabManager.swift b/Sources/TabManager.swift
index 1b7f3701..2c4cadaf 100644
--- a/Sources/TabManager.swift
+++ b/Sources/TabManager.swift
@@ -913,18 +913,10 @@ class TabManager: ObservableObject {
         let activeProbeKeys = Set(workspaceGitProbeGenerationByKey.keys)
 
         for workspace in tabs {
-            var candidatePanelIds = Set(workspace.panelGitBranches.keys)
-            candidatePanelIds.formUnion(workspace.panelPullRequests.keys)
-
-            if candidatePanelIds.isEmpty,
-               let focusedPanelId = workspace.focusedPanelId,
-               workspace.gitBranch != nil || workspace.pullRequest != nil {
-                candidatePanelIds.insert(focusedPanelId)
-            }
-
-            for panelId in candidatePanelIds {
-                let probeKey = WorkspaceGitProbeKey(workspaceId: workspace.id, panelId: panelId)
-                guard !activeProbeKeys.contains(probeKey) else { continue }
+            for panelId in trackedWorkspaceGitMetadataPollCandidatePanelIds(
+                in: workspace,
+                activeProbeKeys: activeProbeKeys
+            ) {
                 scheduleWorkspaceGitMetadataRefreshIfPossible(
                     workspaceId: workspace.id,
                     panelId: panelId,
@@ -938,6 +930,54 @@ class TabManager: ObservableObject {
         refreshTrackedWorkspaceGitMetadata()
     }
 
+    func trackedWorkspaceGitMetadataPollCandidatePanelIdsForTesting(workspaceId: UUID) -> Set<UUID> {
+        let activeProbeKeys = Set(workspaceGitProbeGenerationByKey.keys)
+        guard let workspace = tabs.first(where: { $0.id == workspaceId }) else {
+            return []
+        }
+        return trackedWorkspaceGitMetadataPollCandidatePanelIds(
+            in: workspace,
+            activeProbeKeys: activeProbeKeys
+        )
+    }
+
+    private func trackedWorkspaceGitMetadataPollCandidatePanelIds(
+        in workspace: Workspace,
+        activeProbeKeys: Set<WorkspaceGitProbeKey>
+    ) -> Set<UUID> {
+        var candidatePanelIds = Set(workspace.panelGitBranches.keys)
+        candidatePanelIds.formUnion(workspace.panelPullRequests.keys)
+
+        if candidatePanelIds.isEmpty,
+           let focusedPanelId = workspace.focusedPanelId,
+           workspace.gitBranch != nil || workspace.pullRequest != nil {
+            candidatePanelIds.insert(focusedPanelId)
+        }
+
+        return Set(candidatePanelIds.filter { panelId in
+            let probeKey = WorkspaceGitProbeKey(workspaceId: workspace.id, panelId: panelId)
+            guard !activeProbeKeys.contains(probeKey) else { return false }
+            return shouldPollTrackedWorkspaceGitMetadata(in: workspace, panelId: panelId)
+        })
+    }
+
+    private func shouldPollTrackedWorkspaceGitMetadata(in workspace: Workspace, panelId: UUID) -> Bool {
+        guard let branch = trackedWorkspaceGitBranch(in: workspace, panelId: panelId) else {
+            return true
+        }
+        return !Self.shouldSkipWorkspacePullRequestLookup(branch: branch)
+    }
+
+    private func trackedWorkspaceGitBranch(in workspace: Workspace, panelId: UUID) -> String? {
+        if let branch = workspace.panelGitBranches[panelId]?.branch {
+            return branch
+        }
+        if workspace.focusedPanelId == panelId {
+            return workspace.gitBranch?.branch
+        }
+        return nil
+    }
+
     private func sweepStaleAgentPIDs() {
         for tab in tabs {
             var keysToRemove: [String] = []
@@ -1462,6 +1502,10 @@ class TabManager: ObservableObject {
         directory: String,
         branch: String
     ) -> WorkspacePullRequestSnapshot {
+        guard !shouldSkipWorkspacePullRequestLookup(branch: branch) else {
+            return .notFound
+        }
+
         let repoSlugs = githubRepositorySlugs(directory: directory)
         guard !repoSlugs.isEmpty else {
             return .unsupportedRepository
@@ -2010,6 +2054,15 @@ class TabManager: ObservableObject {
         return trimmed.isEmpty ? nil : trimmed
     }
 
+    nonisolated static func shouldSkipWorkspacePullRequestLookup(branch: String) -> Bool {
+        switch normalizedBranchName(branch) {
+        case "main", "master":
+            return true
+        default:
+            return false
+        }
+    }
+
     func requestBackgroundWorkspaceLoad(for workspaceId: UUID) {
         guard !pendingBackgroundWorkspaceLoadIds.contains(workspaceId) else { return }
         var updated = pendingBackgroundWorkspaceLoadIds
diff --git a/cmuxTests/TabManagerUnitTests.swift b/cmuxTests/TabManagerUnitTests.swift
index 78920716..d8ec097a 100644
--- a/cmuxTests/TabManagerUnitTests.swift
+++ b/cmuxTests/TabManagerUnitTests.swift
@@ -301,6 +301,72 @@ final class TabManagerPullRequestProbeTests: XCTestCase {
         )
     }
 
+    func testShouldSkipWorkspacePullRequestLookupOnlyForExactMainAndMaster() {
+        XCTAssertTrue(TabManager.shouldSkipWorkspacePullRequestLookup(branch: "main"))
+        XCTAssertTrue(TabManager.shouldSkipWorkspacePullRequestLookup(branch: "master"))
+        XCTAssertTrue(TabManager.shouldSkipWorkspacePullRequestLookup(branch: " master \n"))
+
+        XCTAssertFalse(TabManager.shouldSkipWorkspacePullRequestLookup(branch: "Main"))
+        XCTAssertFalse(TabManager.shouldSkipWorkspacePullRequestLookup(branch: "mainline"))
+        XCTAssertFalse(TabManager.shouldSkipWorkspacePullRequestLookup(branch: "feature/main"))
+        XCTAssertFalse(TabManager.shouldSkipWorkspacePullRequestLookup(branch: "release/master-fix"))
+    }
+
+    func testTrackedWorkspaceGitMetadataPollCandidatesSkipMainAndMasterPanelsOnly() throws {
+        let manager = TabManager()
+        guard let workspace = manager.selectedWorkspace,
+              let mainPanelId = workspace.focusedPanelId else {
+            XCTFail("Expected selected workspace with focused panel")
+            return
+        }
+
+        guard let masterPanel = workspace.newTerminalSplit(from: mainPanelId, orientation: .horizontal),
+              let featurePanel = workspace.newTerminalSplit(from: mainPanelId, orientation: .vertical),
+              let mainlinePanel = workspace.newTerminalSplit(from: mainPanelId, orientation: .horizontal) else {
+            XCTFail("Expected split panels to be created")
+            return
+        }
+
+        let staleURL = try XCTUnwrap(URL(string: "https://github.com/manaflow-ai/cmux/pull/371"))
+        workspace.updatePanelGitBranch(panelId: mainPanelId, branch: "main", isDirty: false)
+        workspace.updatePanelPullRequest(
+            panelId: mainPanelId,
+            number: 371,
+            label: "PR",
+            url: staleURL,
+            status: .open,
+            branch: "main"
+        )
+        workspace.updatePanelGitBranch(panelId: masterPanel.id, branch: "master", isDirty: false)
+        workspace.updatePanelGitBranch(panelId: featurePanel.id, branch: "feature/sidebar-pr", isDirty: false)
+        workspace.updatePanelGitBranch(panelId: mainlinePanel.id, branch: "mainline", isDirty: false)
+
+        XCTAssertEqual(
+            manager.trackedWorkspaceGitMetadataPollCandidatePanelIdsForTesting(workspaceId: workspace.id),
+            Set([featurePanel.id, mainlinePanel.id])
+        )
+    }
+
+    func testTrackedWorkspaceGitMetadataPollCandidatesSkipFocusedFallbackOnMainOnly() {
+        let manager = TabManager()
+        guard let workspace = manager.selectedWorkspace,
+              let panelId = workspace.focusedPanelId else {
+            XCTFail("Expected selected workspace with focused panel")
+            return
+        }
+
+        workspace.gitBranch = SidebarGitBranchState(branch: "main", isDirty: false)
+        XCTAssertTrue(
+            manager.trackedWorkspaceGitMetadataPollCandidatePanelIdsForTesting(workspaceId: workspace.id).isEmpty
+        )
+
+        workspace.gitBranch = SidebarGitBranchState(branch: "feature/sidebar-pr", isDirty: false)
+        XCTAssertEqual(
+            manager.trackedWorkspaceGitMetadataPollCandidatePanelIdsForTesting(workspaceId: workspace.id),
+            Set([panelId])
+        )
+    }
+
     func testResolvedCommandPathFallsBackOutsideAppPATH() throws {
         let fileManager = FileManager.default
         let tempDir = fileManager.temporaryDirectory.appendingPathComponent(