diff --git a/github/index.ts b/github/index.ts
index fc32083b..38bafd36 100644
--- a/github/index.ts
+++ b/github/index.ts
@@ -113,10 +113,6 @@ type IssueQueryResponse = {
 }
 
 const { client, server } = createOpencode()
-let input = {
-  mockEvent: process.env["MOCK_EVENT"],
-  mockToken: process.env["MOCK_TOKEN"],
-}
 let accessToken: string
 let octoRest: Octokit
 let octoGraph: typeof graphql
@@ -150,8 +146,8 @@ try {
   session = await client.session.create<true>().then((r) => r.data)
   await subscribeSessionEvents()
   shareId = await (async () => {
-    if (useShare() === false) return
-    if (!useShare() && repoData.data.private) return
+    if (useEnvShare() === false) return
+    if (!useEnvShare() && repoData.data.private) return
     await client.session.share<true>({ path: session })
     return session.id.slice(-8)
   })()
@@ -274,23 +270,7 @@ function assertContextEvent(...events: string[]) {
   return context
 }
 
-function isMock() {
-  const { mockEvent, mockToken } = input
-  return Boolean(mockEvent || mockToken)
-}
-
-function isPullRequest() {
-  const context = useContext()
-  const payload = context.payload as IssueCommentEvent
-  return Boolean(payload.issue.pull_request)
-}
-
-function useContext() {
-  const { mockEvent } = input
-  return isMock() ? (JSON.parse(mockEvent!) as GitHubContext) : github.context
-}
-
-function useModel() {
+function useEnvModel() {
   const value = process.env["MODEL"]
   if (!value) throw new Error(`Environment variable "MODEL" is not set`)
 
@@ -302,7 +282,7 @@ function useModel() {
   return { providerID, modelID }
 }
 
-function useRunUrl() {
+function useEnvRunUrl() {
   const { repo } = useContext()
 
   const runId = process.env["GITHUB_RUN_ID"]
@@ -311,7 +291,7 @@ function useRunUrl() {
   return `/${repo.owner}/${repo.repo}/actions/runs/${runId}`
 }
 
-function useShare() {
+function useEnvShare() {
   const value = process.env["SHARE"]
   if (!value) return undefined
   if (value === "true") return true
@@ -319,6 +299,33 @@ function useShare() {
   throw new Error(`Invalid share value: ${value}. Share must be a boolean.`)
 }
 
+function useEnvMock() {
+  return {
+    mockEvent: process.env["MOCK_EVENT"],
+    mockToken: process.env["MOCK_TOKEN"],
+  }
+}
+
+function useEnvGithubApp() {
+  if (process.env["USE_GITHUB_APP"]?.toLowerCase() === "false") return false
+  return true
+}
+
+function isMock() {
+  const { mockEvent, mockToken } = useEnvMock()
+  return Boolean(mockEvent || mockToken)
+}
+
+function isPullRequest() {
+  const context = useContext()
+  const payload = context.payload as IssueCommentEvent
+  return Boolean(payload.issue.pull_request)
+}
+
+function useContext() {
+  return isMock() ? (JSON.parse(useEnvMock().mockEvent!) as GitHubContext) : github.context
+}
+
 function useIssueId() {
   const payload = useContext().payload as IssueCommentEvent
   return payload.issue.number
@@ -331,12 +338,14 @@ function useShareUrl() {
 async function getAccessToken() {
   const { repo } = useContext()
 
+  if (useEnvGithubApp()) return await core.getIDToken("opencode-github-action")
+
   let response
   if (isMock()) {
     response = await fetch("https://api.opencode.ai/exchange_github_app_token_with_pat", {
       method: "POST",
       headers: {
-        Authorization: `Bearer ${input.mockToken}`,
+        Authorization: `Bearer ${useEnvMock().mockToken}`,
       },
       body: JSON.stringify({ owner: repo.owner, repo: repo.repo }),
     })
@@ -366,7 +375,7 @@ async function createComment() {
     owner: repo.owner,
     repo: repo.repo,
     issue_number: useIssueId(),
-    body: `[Working...](${useRunUrl()})`,
+    body: `[Working...](${useEnvRunUrl()})`,
   })
 }
 
@@ -525,7 +534,7 @@ async function summarize(response: string) {
 
 async function chat(text: string, files: PromptFiles = []) {
   console.log("Sending message to opencode...")
-  const { providerID, modelID } = useModel()
+  const { providerID, modelID } = useEnvModel()
 
   const chat = await client.session.chat<true>({
     path: session,
@@ -722,7 +731,7 @@ async function createPR(base: string, branch: string, title: string, body: strin
 }
 
 function footer(opts?: { image?: boolean }) {
-  const { providerID, modelID } = useModel()
+  const { providerID, modelID } = useEnvModel()
 
   const image = (() => {
     if (!shareId) return ""
@@ -734,7 +743,7 @@ function footer(opts?: { image?: boolean }) {
     return `<a href="${useShareUrl()}/s/${shareId}"><img width="200" alt="${titleAlt}" src="https://social-cards.sst.dev/opencode-share/${title64}.png?model=${providerID}/${modelID}&version=${session.version}&id=${shareId}" /></a>\n`
   })()
   const shareUrl = shareId ? `[opencode session](${useShareUrl()}/s/${shareId})&nbsp;&nbsp;|&nbsp;&nbsp;` : ""
-  return `\n\n${image}${shareUrl}[github run](${useRunUrl()})`
+  return `\n\n${image}${shareUrl}[github run](${useEnvRunUrl()})`
 }
 
 async function fetchRepo() {