Windows: app file tools report content exclusion while another Copilot CLI session can read ARCHITECTURE.md

Summary

In a GitHub Copilot app worktree session, built-in file reads and searches repeatedly fail with an organization content-exclusion error. I can access the private repository, and another Copilot CLI session can read ARCHITECTURE.md, as shown in a screenshot I supplied to the app session.

Please investigate whether this is an intended client-policy difference, an incorrect policy evaluation, or a misleading error. The root cause is not established. This report concerns the Copilot app's file-access behavior, not the repository's application code.

Environment

• Observed: September 8, 2026.
• OS: Microsoft Windows 11 Enterprise, version 10.0.26200, build 26200.
• GitHub Copilot app: local, worktree-backed session against a private enterprise-hosted repository.
• Desktop app version: not captured.
• Agent runtime version reported in the affected session: 1.0.83-5 (not the desktop app version).
• Comparison CLI version: not captured.

Private repository identifiers, local username, session ID, and commit IDs are omitted from this public report. No source code or raw diagnostic bundle is included.

Steps observed

1. Open the private repository in a local Copilot app worktree session.
2. Ask the agent to pull the latest main and investigate the repository architecture.
3. git pull --ff-only origin main succeeds with Already up to date.
4. The app agent calls the built-in view tool on the worktree's ARCHITECTURE.md.
5. The tool rejects the read with the error below.
6. Ask the agent to retry. A second call to the same view tool, requesting lines 1-80, fails identically.
7. Built-in glob searches across several source directories also return content-exclusion errors rather than results.

Actual behavior

The file-reading tool repeatedly returns this message (only the path identifiers are redacted):

Access denied: "C:\Users\<user>\repos\copilot-worktrees\<repo>\<worktree>\ARCHITECTURE.md" is excluded by organization content policy. Do not attempt to access this file.

Reads of the root instructions file and searches under .github also received the same class of denial. The app agent stopped the code investigation rather than attempting to bypass the denied tools.

Contrasting CLI evidence

My screenshot of another CLI session shows:

Search "ARCHITECTURE.md" 4 files found
Read ARCHITECTURE.md L1:150 (150 lines read)

These lines are transcribed from the screenshot; the raw screenshot is not attached because it includes private repository-specific context. The affected app agent did not independently read the file through another mechanism.

The screenshot does not establish the successful read's absolute path, effective policy, or client identity. It also shows a different pulled commit from the affected session. An identical-path, identical-commit, identical-identity comparison is therefore still needed. Some searches in the comparison session timed out; the demonstrated success is specifically the architecture-file read.

Git access succeeding is not, by itself, evidence that agent content policy should permit reading. The discrepancy needing explanation is the app's repeated file-tool denials versus the other CLI session's successful read.

Expected behavior

Equivalent app/CLI sessions using the same repository, revision, identity, and effective policy should behave consistently, or explain any intentional difference clearly.

If the exclusion is legitimate, preserve it and provide actionable diagnostics identifying the relevant policy source or client limitation without exposing protected content. If another failure is being reported as content exclusion, report the actual cause.

Impact and requested investigation

The app could not complete a repository architecture investigation that another CLI session appeared able to start. The current error gives no actionable explanation of the difference.

Please identify the effective exclusion rule and compare policy evaluation between the clients. Windows worktree/repository mapping, cached policy state, and client-specific policy support are possible investigation areas, not confirmed causes.

No raw /collect-debug-logs bundle was collected or uploaded; any support bundle should be reviewed for sensitive information before sharing.

Reproduce the Windows 11 worktree behavior using the built-in view and glob tools against the same repository, revision, identity, and policy as the comparison CLI session. Compare the app and CLI policy evaluation, including worktree mapping and cached policy state; done means identifying whether the exclusion is legitimate and producing an actionable, accurate diagnostic.