Xcode 26.5 downloads darwin-arm64 Claude Agent binary on Intel Macs, causing exec failure misreported as code-signing error (workaround verified)
On Intel Macs, Xcode 26.5 (build 17F42) downloads the darwin-arm64 build of the Claude Agent rather than the darwin-x64 build that the vendor publishes at the same version. The arm64 binary fails to exec on Intel with NSPOSIXErrorDomain Code=86 ("Bad CPU type in executable") and Xcode's Intelligence subsystem then surfaces this in the UI as a code-signing / sandboxing failure. Replacing the downloaded binary with the parallel darwin-x64 build, and updating the agent's Info.plist checksum and URL to match, results in a fully functional Claude Agent in Xcode 26.5 on the same Intel Mac.
This was verified end to end on the affected hardware.
The agent downloader in Xcode should select the URL matching the host CPU architecture (e.g. by inspecting the result of uname -m or the equivalent in Foundation). This appears to be an isolated fix to whichever component constructs the agent's download URL in Xcode's Intelligence subsystem.
Secondary suggestion: the user-facing error message "the code signing identity for the agent did not match expectations, or the agent violated sandboxing rules" should be revised when the underlying cause is an exec failure (EBADARCH or otherwise). The current wording is misleading and has produced considerable misdirected investigation in the developer community.
USER-SIDE WORKAROUND (VERIFIED) The following restores Claude Agent functionality on this Intel Mac running Xcode 26.5. It may need re-applying after Xcode updates the agent, since the buggy download logic will run again.
- Quit Xcode.
- Download the parallel darwin-x64 binary from the vendor's release bucket (the same URL as in the Info.plist, with "darwin-arm64" replaced by "darwin-x64").
- Make the destination writable, copy in the new binary, restore read-only mode.
- Recompute SHA-512 and update Info.plist's
checksumandurlfields with plutil. - Relaunch Xcode.
Workaround for Intel Mac users (verified)
This restores a working Claude Agent in Xcode 26.5 on Intel until Xcode'sdownloader is fixed. Quit Xcode fully first.
1. Quit Xcode
osascript -e 'tell application "Xcode" to quit' sleep 3
2. Download the correct-arch binary directly from Anthropic's release bucket
curl -fL -o /tmp/claude-x64\ttps://storage.googleapis.com/claude-code-dist-86c565f3-f756-42ad-8dfa-d59b1c096819/claude-code-releases/2.1.118/darwin-x64/claude chmod +x /tmp/claude-x64
3. Verify it's the right arch and properly signed
file /tmp/claude-x64 # → Mach-O 64-bit executable x86_64 codesign --verify --verbose /tmp/claude-x64
4. Replace the arm64 binary Xcode downloaded (destination is read-only by default)
AGENT_DIR=~/Library/Developer/Xcode/CodingAssistant/Agents/XcodeVersions/17F42/claude chmod u+w "$AGENT_DIR/claude" cp -p /tmp/claude-x64 "$AGENT_DIR/claude" chmod a-w "$AGENT_DIR/claude"
5. Update Info.plist so its checksum and URL match the swapped binary
NEW_CHECKSUM=$(shasum -a 512 "$AGENT_DIR/claude" | awk '{print $1}')
plutil -replace checksum -string "$NEW_CHECKSUM" "$AGENT_DIR/Info.plist"
plutil -replace url -string
"https://storage.googleapis.com/claude-code-dist-86c565f3-f756-42ad-8dfa-d59b1c096819/claude-code-releases/2.1.118/darwin-x64/claude"
"$AGENT_DIR/Info.plist"
6. Relaunch Xcode; the Claude Agent now works on Intel.
Caveats
Adjust 17F42 and 2.1.118 to whatever your Xcode build and agent version actually are. Check with ls ~/Library/Developer/Xcode/CodingAssistant/Agents/XcodeVersions/ and the version key in the Info.plist.
The workaround may not survive an Xcode update. If Xcode refreshes the agent (new Claude Code version, new Xcode point release), the buggy download logic will run again and overwrite the x86_64 binary. The same procedure restores working state. Worth saving the commands above as a small shell script so you don't have to re-derive them next time.
ENVIRONMENT
Hardware: MacBook Pro 2019, Intel Core i9 (x86_64) macOS: 26.5 Xcode: 26.5 (build 17F42) Agent: Claude Code 2.1.118 Account: Claude Pro (claude.ai OAuth)
I have tried unsuccessfully to request via 'Apple Feedback Assistant' that the above problem be looked into.
This was their response:
"Thank you for your feedback, it is noted. Engineering has determined that there are currently no plans to address this issue.
This feature relies on the dedicated Neural Engine found on Macs with Apple silicon (M1 or newer) to provide the necessary performance and capabilities. As a result, systems that do not include this hardware are not supported for this specific workflow.
You can close this feedback by selecting "Close Feedback" via the Actions button found above. This Feedback will no longer be monitored, and incoming messages will not be reviewed. "
Clearly no one from the senior engineering team has looked at this or given it any consideration and they are not interested in making a trivial fix within Xcode so that it selects the correct Claude binary for download.
It is frustrating that Apple's response cites the requirement for a 'neural engine found in M-series Macs' , when this is very clear to any developer that Claude does not make use of this feature and it self-evidently works on x86 hardware without it . If anyone has any ideas how to get a response from a helpful senior Xcode developer, I would be most interested.
I can understand Apple are reluctant to put any effort into old hardware, however they still provide an up to date Xcode for the x86 platform and I don't think it is asking too much to fix a simple bug which would make life easier.
