diff --git a/mobile/src/session/github-pr-mutations.ts b/mobile/src/session/github-pr-mutations.ts
index 7d79518f089..dff1775f34d 100644
--- a/mobile/src/session/github-pr-mutations.ts
+++ b/mobile/src/session/github-pr-mutations.ts
@@ -1,6 +1,6 @@
 import type { GitHubPRMergeMethod } from '../../../src/shared/types'
 import type { RpcClient } from '../transport/rpc-client'
-import { buildGithubPrParams, type GitHubPrRepoSlug } from './github-pr-rpc'
+import { buildGithubPrParams, githubPrRepoSlugParam, type GitHubPrRepoSlug } from './github-pr-rpc'
 
 // Mutation wrappers for the github.* PR surface, split out so github-pr-rpc.ts
 // stays under the max-lines budget. They mirror the read wrappers' shape but
@@ -105,7 +105,7 @@ export async function fetchUpdatePRTitle(
   // METHODS_ACCEPTING_PR_REPO read allow-list — pass it explicitly so it reaches the
   // host schema (which declares it optional/nullable).
   if (args.prRepo) {
-    params.prRepo = { owner: args.prRepo.owner, repo: args.prRepo.repo }
+    params.prRepo = githubPrRepoSlugParam(args.prRepo)
   }
   const response = await sendRaw(
     client,
@@ -226,7 +226,7 @@ export async function fetchAddPRReviewCommentReply(
   // centralized METHODS_ACCEPTING_PR_REPO allow-list (read-focused) — pass it
   // explicitly so it reaches the host schema, which declares it optional.
   if (args.prRepo) {
-    params.prRepo = { owner: args.prRepo.owner, repo: args.prRepo.repo }
+    params.prRepo = githubPrRepoSlugParam(args.prRepo)
   }
   return sendGithubPrMutation(
     client,
@@ -247,7 +247,7 @@ export async function fetchAddIssueComment(
     type: 'pr'
   }
   if (args.prRepo) {
-    params.prRepo = { owner: args.prRepo.owner, repo: args.prRepo.repo }
+    params.prRepo = githubPrRepoSlugParam(args.prRepo)
   }
   return sendGithubPrMutation(
     client,
diff --git a/mobile/src/session/github-pr-rpc.ts b/mobile/src/session/github-pr-rpc.ts
index 8fd11f710a8..e24c50e8dfc 100644
--- a/mobile/src/session/github-pr-rpc.ts
+++ b/mobile/src/session/github-pr-rpc.ts
@@ -31,7 +31,13 @@ export {
 
 // Why: a fork PR's head lives in a different owner/repo; the host's SlugRepo
 // (`{ owner, repo }`) identifies it. Only a subset of github.* methods accept it.
-export type GitHubPrRepoSlug = { owner: string; repo: string }
+// Why: `host` must survive the RPC boundary or GHES actions on the host fall
+// back to a same-named github.com repo (src/shared/types.ts identity contract).
+export type GitHubPrRepoSlug = { owner: string; repo: string; host?: string }
+
+export function githubPrRepoSlugParam(slug: GitHubPrRepoSlug): Record<string, string> {
+  return { owner: slug.owner, repo: slug.repo, ...(slug.host ? { host: slug.host } : {}) }
+}
 
 export type GitHubPrReadOutcome<T> = { ok: true; result: T } | { ok: false; error: string }
 
@@ -62,7 +68,7 @@ export function buildGithubPrParams(
     ...params
   }
   if (options?.prRepo && METHODS_ACCEPTING_PR_REPO.has(method) && !('prRepo' in built)) {
-    built.prRepo = { owner: options.prRepo.owner, repo: options.prRepo.repo }
+    built.prRepo = githubPrRepoSlugParam(options.prRepo)
   }
   if (options?.headSha && METHODS_ACCEPTING_HEAD_SHA.has(method) && !('headSha' in built)) {
     built.headSha = options.headSha
diff --git a/mobile/src/session/github-pr-value-readers.ts b/mobile/src/session/github-pr-value-readers.ts
index 6ba8ccd6954..1756d51c59a 100644
--- a/mobile/src/session/github-pr-value-readers.ts
+++ b/mobile/src/session/github-pr-value-readers.ts
@@ -153,7 +153,10 @@ export function readRepoIdentity(value: unknown): GitHubRepositoryIdentity | und
   if (!owner || !repo) {
     return undefined
   }
-  return { owner, repo }
+  // Why: dropping `host` here would strip the GHES identity before every
+  // subsequent PR RPC, forcing the host to re-derive it per call.
+  const host = readString(value.host)
+  return { owner, repo, ...(host ? { host } : {}) }
 }
 
 function readMergeMethod(value: unknown): GitHubPRMergeMethod | undefined {
diff --git a/src/main/git/gh-rate-limit-breaker.ts b/src/main/git/gh-rate-limit-breaker.ts
index cf26b0f0f50..85394f0d540 100644
--- a/src/main/git/gh-rate-limit-breaker.ts
+++ b/src/main/git/gh-rate-limit-breaker.ts
@@ -25,7 +25,13 @@ const FALLBACK_BLOCK_MS: Record<GhRateLimitBucket, number> = {
   graphql: 5 * 60_000
 }
 
-const DEFAULT_SCOPE = 'native:github.com'
+// Why: the runner derives scopes with this builder too — a format drift would
+// silently split blocks from the default-scope reads below.
+export function ghRateLimitScopeKey(runtime: string, host: string): string {
+  return `${runtime}:${host.toLowerCase()}`
+}
+
+const DEFAULT_SCOPE = ghRateLimitScopeKey('native', 'github.com')
 const blockedUntilMsByScopeAndBucket = new Map<string, number>()
 let resetProbe: ((bucket: GhRateLimitBucket) => void) | null = null
 
diff --git a/src/main/git/runner-gh-host-args.test.ts b/src/main/git/runner-gh-host-args.test.ts
index e4168dbaf9a..0bee44eac74 100644
--- a/src/main/git/runner-gh-host-args.test.ts
+++ b/src/main/git/runner-gh-host-args.test.ts
@@ -53,36 +53,56 @@ describe('applyGhHostToArgs', () => {
     ])
   })
 
-  it('qualifies inline long and short repo forms for a GHES host', () => {
+  it('qualifies the inline --repo= form for a GHES host', () => {
     expect(applyGhHostToArgs(['pr', 'list', '--repo=a/b'], 'github.acme-corp.com')).toEqual([
       'pr',
       'list',
       '--repo=github.acme-corp.com/a/b'
     ])
+  })
+
+  it('leaves combined -R short forms untouched (indistinguishable from free-text values)', () => {
     expect(applyGhHostToArgs(['pr', 'list', '-R=a/b'], 'github.acme-corp.com')).toEqual([
       'pr',
       'list',
-      '-R=github.acme-corp.com/a/b'
+      '-R=a/b'
     ])
     expect(applyGhHostToArgs(['pr', 'list', '-Ra/b'], 'github.acme-corp.com')).toEqual([
       'pr',
       'list',
-      '-Rgithub.acme-corp.com/a/b'
+      '-Ra/b'
     ])
   })
 
-  it('leaves --repo untouched for the github.com host (gh default resolution)', () => {
+  it('does not rewrite free-text flag values that merely start with -R', () => {
+    expect(
+      applyGhHostToArgs(
+        ['pr', 'edit', '7', '--title', '-Refactor foo/bar', '--repo', 'a/b'],
+        'github.acme-corp.com'
+      )
+    ).toEqual([
+      'pr',
+      'edit',
+      '7',
+      '--title',
+      '-Refactor foo/bar',
+      '--repo',
+      'github.acme-corp.com/a/b'
+    ])
+  })
+
+  it('qualifies --repo for the github.com host so GH_HOST cannot redirect it', () => {
     expect(applyGhHostToArgs(['pr', 'list', '--repo', 'a/b'], 'github.com')).toEqual([
       'pr',
       'list',
       '--repo',
-      'a/b'
+      'github.com/a/b'
     ])
     expect(applyGhHostToArgs(['pr', 'list', '--repo', 'a/b'], 'GitHub.com')).toEqual([
       'pr',
       'list',
       '--repo',
-      'a/b'
+      'GitHub.com/a/b'
     ])
   })
 
@@ -101,13 +121,10 @@ describe('applyGhHostToArgs', () => {
     ).toEqual(['pr', 'list', '--repo', 'github.acme-corp.com/a/b'])
     expect(
       applyGhHostToArgs(
-        ['pr', 'list', '-R=https://github.acme-corp.com/a/b'],
+        ['pr', 'list', '-R', 'https://github.acme-corp.com/a/b'],
         'github.acme-corp.com'
       )
-    ).toEqual(['pr', 'list', '-R=https://github.acme-corp.com/a/b'])
-    expect(
-      applyGhHostToArgs(['pr', 'list', '-Rgithub.acme-corp.com/a/b'], 'github.acme-corp.com')
-    ).toEqual(['pr', 'list', '-Rgithub.acme-corp.com/a/b'])
+    ).toEqual(['pr', 'list', '-R', 'https://github.acme-corp.com/a/b'])
   })
 
   it('injects --hostname and qualifies --repo together for GHES api calls', () => {
diff --git a/src/main/git/runner.ts b/src/main/git/runner.ts
index 65ff7501b3a..bf8741ee053 100644
--- a/src/main/git/runner.ts
+++ b/src/main/git/runner.ts
@@ -24,6 +24,7 @@ import {
   classifyGhRateLimitBucket,
   createGhRateLimitBlockedError,
   getGhRateLimitBlockedUntilMs,
+  ghRateLimitScopeKey,
   isGhPrimaryRateLimitStderr,
   isGhRateLimitProbe,
   notifyGhPrimaryRateLimit,
@@ -1435,32 +1436,37 @@ export function applyGhHostToArgs(args: string[], host?: string): string[] {
   if (result[0] === 'api' && !hasGhHostnameFlag(result)) {
     result = ['api', '--hostname', host, ...result.slice(1)]
   }
-  // github.com is gh's default resolution for bare OWNER/REPO shorthand.
-  if (host.toLowerCase() === 'github.com') {
-    return result
-  }
-  return result.map((arg, i) => {
-    const prev = result[i - 1]
-    if (prev === '--repo' || prev === '-R') {
-      return hostQualifiedGhRepoValue(arg, host)
+  // Why: bare OWNER/REPO shorthand resolves against gh's default host — GH_HOST
+  // when set — so github.com must be qualified too, not just GHES, or a
+  // process-level GH_HOST redirects pinned github.com commands.
+  // Combined short forms (`-Ra/b`, `-R=a/b`) are deliberately not rewritten:
+  // no call site uses them, and prefix-matching `-R` corrupts free-text values
+  // of other flags (e.g. a --title that happens to start with `-R`).
+  const qualified: string[] = []
+  for (let i = 0; i < result.length; i += 1) {
+    const arg = result[i]
+    if (arg === '--repo' || arg === '-R') {
+      qualified.push(arg)
+      const value = result[i + 1]
+      if (value !== undefined) {
+        qualified.push(hostQualifiedGhRepoValue(value, host))
+        i += 1
+      }
+      continue
     }
     if (arg.startsWith('--repo=')) {
-      return `--repo=${hostQualifiedGhRepoValue(arg.slice('--repo='.length), host)}`
+      qualified.push(`--repo=${hostQualifiedGhRepoValue(arg.slice('--repo='.length), host)}`)
+      continue
     }
-    if (arg.startsWith('-R=')) {
-      return `-R=${hostQualifiedGhRepoValue(arg.slice('-R='.length), host)}`
-    }
-    if (arg.startsWith('-R') && arg.length > '-R'.length) {
-      return `-R${hostQualifiedGhRepoValue(arg.slice('-R'.length), host)}`
-    }
-    return arg
-  })
+    qualified.push(arg)
+  }
+  return qualified
 }
 
 function ghRateLimitScope(options: GhExecOptions, resolved: ResolvedCommand): string {
   const runtime = resolved.wsl ? `wsl:${resolved.wsl.distro.toLowerCase()}` : 'native'
   const host = options.host ?? options.env?.GH_HOST ?? process.env.GH_HOST ?? 'github.com'
-  return `${runtime}:${host.toLowerCase()}`
+  return ghRateLimitScopeKey(runtime, host)
 }
 
 function assertGhRateLimitScopeAvailable(
diff --git a/src/main/github/client-create-pr.test.ts b/src/main/github/client-create-pr.test.ts
index 1c90e068d83..dd7a3fd0c70 100644
--- a/src/main/github/client-create-pr.test.ts
+++ b/src/main/github/client-create-pr.test.ts
@@ -60,6 +60,14 @@ vi.mock('./github-enterprise-repository', () => ({
 
 import { createGitHubPullRequest } from './client'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('createGitHubPullRequest', () => {
   beforeEach(() => {
     ghExecFileAsyncMock.mockReset()
@@ -259,7 +267,7 @@ describe('createGitHubPullRequest', () => {
       url: 'https://github.com/acme/widgets/pull/45'
     })
 
-    expect(getOwnerRepoMock).toHaveBeenCalledWith('/remote/repo-root', 'ssh-1')
+    expect(getOwnerRepoMock).toHaveBeenCalledWith('/remote/repo-root', 'ssh-1', {})
     const [args, options] = ghExecFileAsyncMock.mock.calls[0]
     expect(args).toEqual(
       expect.arrayContaining([
@@ -417,7 +425,9 @@ describe('createGitHubPullRequest', () => {
         '--json',
         'number,url'
       ],
-      { cwd: '/repo-root' }
+      // Why: dotcom slugs resolve with host:'github.com' so creation stays
+      // pinned against a process-level GH_HOST.
+      { cwd: '/repo-root', host: 'github.com' }
     ])
   })
 
diff --git a/src/main/github/client-file-viewed.test.ts b/src/main/github/client-file-viewed.test.ts
index 79ad4e6a752..d00f34a3433 100644
--- a/src/main/github/client-file-viewed.test.ts
+++ b/src/main/github/client-file-viewed.test.ts
@@ -45,6 +45,14 @@ vi.mock('./github-enterprise-repository', () => ({
 
 import { setPRFileViewed } from './client'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('setPRFileViewed', () => {
   beforeEach(() => {
     ghExecFileAsyncMock.mockReset()
diff --git a/src/main/github/client-pr-checks.test.ts b/src/main/github/client-pr-checks.test.ts
index 82310af697b..782fa277d39 100644
--- a/src/main/github/client-pr-checks.test.ts
+++ b/src/main/github/client-pr-checks.test.ts
@@ -80,6 +80,14 @@ vi.mock('./rate-limit', () => ({
 
 import { getPRChecks, rerunPRChecks, _resetOwnerRepoCache } from './client'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 function graphQLChecksResponse({
   contexts = [],
   checkSuites = [],
diff --git a/src/main/github/client-pr-local-runtime.test.ts b/src/main/github/client-pr-local-runtime.test.ts
index 8e19df99f56..03c00cd0802 100644
--- a/src/main/github/client-pr-local-runtime.test.ts
+++ b/src/main/github/client-pr-local-runtime.test.ts
@@ -122,6 +122,14 @@ import {
   updatePRTitle
 } from './client'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('GitHub PR local runtime routing', () => {
   beforeEach(() => {
     execFileAsyncMock.mockReset()
diff --git a/src/main/github/client-work-items.test.ts b/src/main/github/client-work-items.test.ts
index 70fe8fc2804..35191c3be20 100644
--- a/src/main/github/client-work-items.test.ts
+++ b/src/main/github/client-work-items.test.ts
@@ -20,7 +20,7 @@ const {
   getOwnerRepoForRemoteMock: vi.fn(),
   resolveIssueSourceMock: vi.fn(),
   gitExecFileAsyncMock: vi.fn(),
-  rateLimitGuardMock: vi.fn(() => ({ blocked: false })),
+  rateLimitGuardMock: vi.fn((_bucket?: unknown) => ({ blocked: false })),
   noteRateLimitSpendMock: vi.fn(),
   acquireMock: vi.fn(),
   releaseMock: vi.fn()
@@ -65,8 +65,11 @@ vi.mock('./rate-limit', () => ({
   rateLimitGuard: rateLimitGuardMock,
   noteRateLimitSpend: noteRateLimitSpendMock,
   getRateLimit: vi.fn(async () => ({ ok: false, error: 'not probed in tests' })),
-  repositoryRateLimitGuard: vi.fn(() => ({ blocked: false })),
-  noteRepositoryRateLimitSpend: vi.fn(),
+  // Mirror production: shared-scope calls delegate to the global guard/spend.
+  repositoryRateLimitGuard: vi.fn((_repo: unknown, bucket: string) => rateLimitGuardMock(bucket)),
+  noteRepositoryRateLimitSpend: vi.fn((_repo: unknown, bucket: string, cost?: number) =>
+    noteRateLimitSpendMock(bucket, cost)
+  ),
   spendsSharedGitHubComQuota: () => true
 }))
 
@@ -79,6 +82,14 @@ import {
 import { _resetGhCwdRepoNegativeCache } from './gh-cwd-repo-negative-cache'
 import { GITHUB_WORK_ITEMS_QUERY_MAX_BYTES } from '../../shared/github-work-items-query-bounds'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('listWorkItems', () => {
   beforeEach(() => {
     execFileAsyncMock.mockReset()
diff --git a/src/main/github/client.test.ts b/src/main/github/client.test.ts
index 2a3c102f0c0..86d12c075ee 100644
--- a/src/main/github/client.test.ts
+++ b/src/main/github/client.test.ts
@@ -134,6 +134,14 @@ import {
 import { __resetPRConflictSummaryCachesForTests } from './conflict-summary'
 import { resetMergedPRCommitMembershipCacheForTest } from './merged-pr-commit-membership'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('checkOrcaStarred', () => {
   beforeEach(() => {
     execFileAsyncMock.mockReset()
diff --git a/src/main/github/client.ts b/src/main/github/client.ts
index 1b24d97648b..5e31b44dfb9 100644
--- a/src/main/github/client.ts
+++ b/src/main/github/client.ts
@@ -79,7 +79,6 @@ import {
   rememberGhCwdResolutionFailure
 } from './gh-cwd-repo-negative-cache'
 import type { GitHubRepoContext } from './github-repository-identity'
-import { getEnterpriseGitHubRepoSlug } from './github-enterprise-repository'
 import {
   getOriginGitHubApiRepository,
   githubHostExecOptions,
@@ -111,7 +110,6 @@ import {
 import { mapGraphQLReactionGroups, type GitHubGraphQLReactionGroup } from './comment-reactions'
 import {
   getRateLimit,
-  noteRateLimitSpend,
   noteRepositoryRateLimitSpend,
   rateLimitGuard,
   repositoryRateLimitGuard,
@@ -1520,7 +1518,7 @@ async function countWorkItemsForQuery(
   )
   // Why: over-counts gh cache hits, which is the safe direction — the search
   // bucket is only 30/min and the next probe corrects the estimate.
-  noteRateLimitSpend('search')
+  noteRepositoryRateLimitSpend(ownerRepo, 'search', 1, localGitOptions)
   return Number.parseInt(stdout.trim(), 10) || 0
 }
 
@@ -1580,8 +1578,11 @@ export async function countWorkItems(
   // 30/min, so a multi-repo Tasks page must stop counting when the budget is
   // gone instead of converting the remaining repos into 403 spawns. getRateLimit
   // is 30s-cached and single-flight, so priming here is one spawn per window.
-  await getRateLimit()
-  if (rateLimitGuard('search').blocked) {
+  // Only shared github.com traffic consults the snapshot; other scopes bypass.
+  if (spendsSharedGitHubComQuota(ownerRepo, localGitOptions)) {
+    await getRateLimit()
+  }
+  if (repositoryRateLimitGuard(ownerRepo, 'search', localGitOptions).blocked) {
     return 0
   }
 
@@ -1876,11 +1877,14 @@ export async function createGitHubPullRequest(
     }
   }
 
-  // Why: github.com-only slug parsing returns null for GHES, so fall back to the
-  // enterprise resolver (gh-authenticated custom host) before giving up (#8312).
-  const ownerRepo =
-    (await getOwnerRepo(repoPath, connectionId, ...hostedReviewLocalGitOptionArgs(options))) ??
-    (await getEnterpriseGitHubRepoSlug(repoPath, connectionId, options))
+  // Why: the shared origin resolver covers GHES fallback and stamps
+  // host:'github.com' on dotcom slugs, keeping creation pinned against GH_HOST
+  // like every other PR path (#8312).
+  const ownerRepo = await getOriginGitHubApiRepository(
+    repoPath,
+    connectionId,
+    getHostedReviewLocalGitOptions(options)
+  )
   if (!ownerRepo) {
     return {
       ok: false,
@@ -4359,7 +4363,7 @@ export async function getPRComments(
       ['pr', 'view', String(prNumber), '--json', 'comments'],
       ghOptions
     )
-    noteRateLimitSpend('graphql')
+    noteRepositoryRateLimitSpend(ownerRepo, 'graphql', 1, ghOptions)
     const data = JSON.parse(stdout) as {
       comments: {
         author: { login: string }
diff --git a/src/main/github/github-api-repository.ts b/src/main/github/github-api-repository.ts
index cd7284dd90e..571ec5a5b2d 100644
--- a/src/main/github/github-api-repository.ts
+++ b/src/main/github/github-api-repository.ts
@@ -1,9 +1,31 @@
 import type { GitHubOwnerRepo } from '../../shared/types'
+import { isDefaultGitHubHost } from '../../shared/github-repository-identity-key'
 import { getOwnerRepo, type LocalGitExecOptions } from './gh-utils'
 import { getEnterpriseGitHubRepoSlug } from './github-enterprise-repository'
 
 export type GitHubApiRepository = GitHubOwnerRepo
 
+// Why: the enterprise branch spawns an uncached `git remote get-url` (an SSH
+// round trip on connection-backed repos) — hot paths like per-file contents
+// and viewed-state toggles resolve per call, so cache like ownerRepoCache does.
+const ORIGIN_REPO_CACHE_TTL_MS = 30_000
+const originRepoCache = new Map<string, { value: GitHubApiRepository | null; expiresAt: number }>()
+const originRepoInFlight = new Map<string, Promise<GitHubApiRepository | null>>()
+
+function originRepoCacheKey(
+  repoPath: string,
+  connectionId?: string | null,
+  localGitOptions: LocalGitExecOptions = {}
+): string {
+  return `${connectionId ?? 'local'}\0${localGitOptions.wslDistro ?? ''}\0${repoPath}`
+}
+
+/** @internal - exposed for tests only */
+export function _resetOriginGitHubApiRepositoryCache(): void {
+  originRepoCache.clear()
+  originRepoInFlight.clear()
+}
+
 export async function getOriginGitHubApiRepository(
   repoPath: string,
   connectionId?: string | null,
@@ -13,9 +35,30 @@ export async function getOriginGitHubApiRepository(
   if (ownerRepo) {
     return { ...ownerRepo, host: 'github.com' }
   }
-  const enterpriseOptions =
-    Object.keys(localGitOptions).length > 0 ? { localGitExecOptions: localGitOptions } : {}
-  return getEnterpriseGitHubRepoSlug(repoPath, connectionId, enterpriseOptions)
+  const cacheKey = originRepoCacheKey(repoPath, connectionId, localGitOptions)
+  const cached = originRepoCache.get(cacheKey)
+  if (cached && cached.expiresAt > Date.now()) {
+    return cached.value
+  }
+  const inFlight = originRepoInFlight.get(cacheKey)
+  if (inFlight) {
+    return inFlight
+  }
+  const probe = (async () => {
+    const enterpriseOptions =
+      Object.keys(localGitOptions).length > 0 ? { localGitExecOptions: localGitOptions } : {}
+    const slug = await getEnterpriseGitHubRepoSlug(repoPath, connectionId, enterpriseOptions)
+    originRepoCache.set(cacheKey, { value: slug, expiresAt: Date.now() + ORIGIN_REPO_CACHE_TTL_MS })
+    return slug
+  })()
+  originRepoInFlight.set(cacheKey, probe)
+  try {
+    return await probe
+  } finally {
+    if (originRepoInFlight.get(cacheKey) === probe) {
+      originRepoInFlight.delete(cacheKey)
+    }
+  }
 }
 
 export async function resolveGitHubApiRepository(
@@ -46,7 +89,7 @@ export async function resolveGitHubApiRepository(
 }
 
 export function isGitHubDotComRepository(repository: GitHubApiRepository): boolean {
-  return !repository.host || repository.host.toLowerCase() === 'github.com'
+  return isDefaultGitHubHost(repository.host)
 }
 
 // Why: the gh runner host-qualifies argv from `options.host`, so every known
diff --git a/src/main/github/issues.test.ts b/src/main/github/issues.test.ts
index e804a6cbc5c..7ff695ba12d 100644
--- a/src/main/github/issues.test.ts
+++ b/src/main/github/issues.test.ts
@@ -37,6 +37,14 @@ import {
   updateIssue
 } from './issues'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('issue source operations', () => {
   beforeEach(() => {
     ghExecFileAsyncMock.mockReset()
diff --git a/src/main/github/rate-limit.ts b/src/main/github/rate-limit.ts
index 721c0b52f76..d3a4a4a056f 100644
--- a/src/main/github/rate-limit.ts
+++ b/src/main/github/rate-limit.ts
@@ -18,6 +18,7 @@ import type {
   GitHubRateLimitBucket,
   GitHubRateLimitSnapshot
 } from '../../shared/types'
+import { isDefaultGitHubHost } from '../../shared/github-repository-identity-key'
 import { acquire, release } from './gh-utils'
 import { ghExecFileAsync } from '../git/runner'
 import {
@@ -168,8 +169,7 @@ export function spendsSharedGitHubComQuota(
   repository: { host?: string } | null | undefined,
   executionOptions?: { wslDistro?: string }
 ): boolean {
-  const host = repository?.host
-  return (!host || host.toLowerCase() === 'github.com') && !executionOptions?.wslDistro
+  return isDefaultGitHubHost(repository?.host) && !executionOptions?.wslDistro
 }
 
 export function repositoryRateLimitGuard(
diff --git a/src/main/github/work-item-details-file-viewed.test.ts b/src/main/github/work-item-details-file-viewed.test.ts
index b8816bf4e0b..3ebe70aa1d6 100644
--- a/src/main/github/work-item-details-file-viewed.test.ts
+++ b/src/main/github/work-item-details-file-viewed.test.ts
@@ -61,6 +61,14 @@ vi.mock('./rate-limit', () => ({
 
 import { getWorkItemDetails } from './work-item-details'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('getWorkItemDetails PR file viewed state', () => {
   beforeEach(() => {
     ghExecFileAsyncMock.mockReset()
diff --git a/src/main/github/work-item-details-pr-files.test.ts b/src/main/github/work-item-details-pr-files.test.ts
index cbd043fe996..092b800a807 100644
--- a/src/main/github/work-item-details-pr-files.test.ts
+++ b/src/main/github/work-item-details-pr-files.test.ts
@@ -48,6 +48,14 @@ vi.mock('./rate-limit', () => ({
 
 import { getWorkItemDetails } from './work-item-details'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 function pullRequestItem(number: number, title: string): Record<string, unknown> {
   return {
     id: `pr:${number}`,
diff --git a/src/main/github/work-item-details.test.ts b/src/main/github/work-item-details.test.ts
index cfb6641fda9..3c39a252df5 100644
--- a/src/main/github/work-item-details.test.ts
+++ b/src/main/github/work-item-details.test.ts
@@ -78,6 +78,14 @@ vi.mock('./rate-limit', () => ({
 
 import { getPRFileContents, getWorkItemDetails } from './work-item-details'
 
+import { _resetOriginGitHubApiRepositoryCache } from './github-api-repository'
+
+// The origin-repository cache is module-level state; reset it so slugs
+// resolved by one test cannot leak into the next.
+beforeEach(() => {
+  _resetOriginGitHubApiRepositoryCache()
+})
+
 describe('getWorkItemDetails', () => {
   beforeEach(() => {
     ghExecFileAsyncMock.mockReset()
diff --git a/src/main/github/work-item-details.ts b/src/main/github/work-item-details.ts
index b76508f8653..1af2c90ad4b 100644
--- a/src/main/github/work-item-details.ts
+++ b/src/main/github/work-item-details.ts
@@ -1086,14 +1086,15 @@ export async function getWorkItemDetails(
       : await getOriginGitHubApiRepository(repoPath, connectionId, localGitOptions)
   // Why: SSH-backed gh runs without a cwd, so an unresolved PR repository must
   // not fall through to gh's default host and show a same-number github.com PR.
-  if (connectionId && type === 'pr' && !originApiRepository) {
+  // Covers type-less lookups too — they can also reach the PR path below.
+  if (connectionId && type !== 'issue' && !originApiRepository) {
     return null
   }
   // Why: connection-backed repos have no local cwd for gh to inspect, so GHES
   // must use its host-qualified repository identity during the initial lookup.
   const useExplicitEnterpriseRepository =
     type === 'pr' && originApiRepository !== null && !isGitHubDotComRepository(originApiRepository)
-  const item: Omit<GitHubWorkItem, 'repoId'> | null = useExplicitEnterpriseRepository
+  let item: Omit<GitHubWorkItem, 'repoId'> | null = useExplicitEnterpriseRepository
     ? await getWorkItemByOwnerRepo(
         repoPath,
         originApiRepository,
@@ -1109,6 +1110,17 @@ export async function getWorkItemDetails(
         connectionId,
         ...localGitOptionArgs(localGitOptions)
       )
+  if (!item && useExplicitEnterpriseRepository && !connectionId) {
+    // Why: on a local fork checkout the PR lives on the base repo, which the
+    // origin slug can't see — the cwd lets gh resolve the actual remote.
+    item = await getWorkItem(
+      repoPath,
+      number,
+      type,
+      connectionId,
+      ...localGitOptionArgs(localGitOptions)
+    )
+  }
   if (!item) {
     return null
   }
diff --git a/src/main/ipc/github.ts b/src/main/ipc/github.ts
index 84afec20c3b..f693a750ed2 100644
--- a/src/main/ipc/github.ts
+++ b/src/main/ipc/github.ts
@@ -474,6 +474,7 @@ export function registerGitHubHandlers(store: Store, stats: StatsCollector): voi
         repoPath: string
         owner: string
         repo: string
+        host?: string
         number: number
         type: 'issue' | 'pr'
       }
@@ -481,7 +482,9 @@ export function registerGitHubHandlers(store: Store, stats: StatsCollector): voi
       const repo = assertRegisteredRepo(args, store)
       return getWorkItemByOwnerRepo(
         repo.path,
-        { owner: args.owner, repo: args.repo },
+        // Why: Enterprise host identity must survive the IPC boundary or the
+        // lookup falls back to gh's default host for a same-named repo.
+        { owner: args.owner, repo: args.repo, ...(args.host ? { host: args.host } : {}) },
         args.number,
         args.type,
         repoConnectionId(repo),
diff --git a/src/main/runtime/orca-runtime.ts b/src/main/runtime/orca-runtime.ts
index 6e1bce48a5a..8a8e8916f93 100644
--- a/src/main/runtime/orca-runtime.ts
+++ b/src/main/runtime/orca-runtime.ts
@@ -13483,7 +13483,7 @@ export class OrcaRuntimeService {
 
   async getRepoWorkItemByOwnerRepo(
     repoSelector: string,
-    ownerRepo: { owner: string; repo: string },
+    ownerRepo: { owner: string; repo: string; host?: string },
     number: number,
     type: 'issue' | 'pr'
   ): Promise<Awaited<ReturnType<typeof getWorkItemByOwnerRepo>>> {
diff --git a/src/main/runtime/rpc/methods/github.ts b/src/main/runtime/rpc/methods/github.ts
index b72019dccac..e10afbd82af 100644
--- a/src/main/runtime/rpc/methods/github.ts
+++ b/src/main/runtime/rpc/methods/github.ts
@@ -26,6 +26,9 @@ const WorkItem = RepoSelector.extend({
 const WorkItemByOwnerRepo = RepoSelector.extend({
   owner: requiredString('Missing owner'),
   ownerRepo: requiredString('Missing repo'),
+  // Why: Enterprise host identity must survive RPC parsing; Zod strips
+  // undeclared fields before the runtime can host-qualify gh requests.
+  host: OptionalString,
   number: z.number().int().positive(),
   type: z.enum(['issue', 'pr'])
 })
@@ -345,7 +348,11 @@ export const GITHUB_METHODS: RpcMethod[] = [
     handler: async (params, { runtime }) =>
       runtime.getRepoWorkItemByOwnerRepo(
         params.repo,
-        { owner: params.owner, repo: params.ownerRepo },
+        {
+          owner: params.owner,
+          repo: params.ownerRepo,
+          ...(params.host ? { host: params.host } : {})
+        },
         params.number,
         params.type
       )
diff --git a/src/main/source-control/hosted-review-creation.test.ts b/src/main/source-control/hosted-review-creation.test.ts
index 04c751d7c3b..abfcd11935e 100644
--- a/src/main/source-control/hosted-review-creation.test.ts
+++ b/src/main/source-control/hosted-review-creation.test.ts
@@ -393,7 +393,7 @@ describe('createHostedReview', () => {
     )
     expect(ghExecFileAsyncMock).toHaveBeenCalledWith(
       ['auth', 'status', '--hostname', 'github.com'],
-      { cwd: '/repo', wslDistro: 'Ubuntu' }
+      { cwd: '/repo', wslDistro: 'Ubuntu', host: 'github.com' }
     )
     expect(createGitHubPullRequestMock).toHaveBeenCalledWith(
       '/repo',
@@ -578,7 +578,7 @@ describe('createHostedReview', () => {
     expect(getUpstreamStatusMock).not.toHaveBeenCalled()
     expect(ghExecFileAsyncMock).toHaveBeenCalledWith(
       ['auth', 'status', '--hostname', 'github.com'],
-      {}
+      { host: 'github.com' }
     )
     expect(createGitHubPullRequestMock).toHaveBeenCalledWith(
       '/remote/repo',
diff --git a/src/main/source-control/hosted-review-creation.ts b/src/main/source-control/hosted-review-creation.ts
index 1e19f1d4fa8..68633a29eeb 100644
--- a/src/main/source-control/hosted-review-creation.ts
+++ b/src/main/source-control/hosted-review-creation.ts
@@ -74,9 +74,13 @@ async function isGitHubAuthenticated(
   }
   await acquire()
   try {
+    // Why: `host` scopes any rate-limit breaker trip to github.com — the host
+    // this probe actually targets — instead of a GH_HOST-derived scope.
     await ghExecFileAsync(
       ['auth', 'status', '--hostname', 'github.com'],
-      connectionId ? {} : { cwd: repoPath, ...getHostedReviewLocalGitOptions(options) }
+      connectionId
+        ? { host: 'github.com' }
+        : { cwd: repoPath, ...getHostedReviewLocalGitOptions(options), host: 'github.com' }
     )
     return true
   } catch {
diff --git a/src/preload/index.ts b/src/preload/index.ts
index d1f0d37ea30..1395d808906 100644
--- a/src/preload/index.ts
+++ b/src/preload/index.ts
@@ -1275,6 +1275,7 @@ const api = {
       repoId?: string
       owner: string
       repo: string
+      host?: string
       number: number
       type: 'issue' | 'pr'
     }): Promise<unknown> => ipcRenderer.invoke('gh:workItemByOwnerRepo', args),
diff --git a/src/renderer/src/components/PullRequestPage.tsx b/src/renderer/src/components/PullRequestPage.tsx
index b53ba354618..93e655c22e9 100644
--- a/src/renderer/src/components/PullRequestPage.tsx
+++ b/src/renderer/src/components/PullRequestPage.tsx
@@ -239,7 +239,9 @@ function parseOwnerRepoFromItemUrl(url: string): GitHubOwnerRepo | null {
     if (segments.length < 2) {
       return null
     }
-    return { owner: segments[0], repo: segments[1] }
+    // Why: the URL proves the host. Leaving it off lets the main process stamp
+    // a GHES origin's host onto what is provably a github.com repo.
+    return { owner: segments[0], repo: segments[1], host: 'github.com' }
   } catch {
     return null
   }
diff --git a/src/shared/github-repository-identity-key.ts b/src/shared/github-repository-identity-key.ts
index cace13fb5ab..b8631ac404b 100644
--- a/src/shared/github-repository-identity-key.ts
+++ b/src/shared/github-repository-identity-key.ts
@@ -1,3 +1,10 @@
+// Why: the github.com-vs-GHES boundary is the core invariant of Enterprise
+// support — cache identity, quota scoping, and exec-host routing must all
+// agree on it, so the predicate lives here once.
+export function isDefaultGitHubHost(host?: string): boolean {
+  return !host || host.toLowerCase() === 'github.com'
+}
+
 // Why: cache keys and equality checks for GitHub repos must include the host,
 // or a GHES repo and a same-named github.com repo would collide. github.com is
 // omitted so pre-Enterprise host-less keys stay stable.
@@ -7,6 +14,5 @@ export function githubRepoIdentityKey(repo: {
   host?: string
 }): string {
   const slug = `${repo.owner.toLowerCase()}/${repo.repo.toLowerCase()}`
-  const host = repo.host?.toLowerCase()
-  return host && host !== 'github.com' ? `${host}/${slug}` : slug
+  return repo.host && !isDefaultGitHubHost(repo.host) ? `${repo.host.toLowerCase()}/${slug}` : slug
 }