resume-auto-cd sets CWD to / when session was created by external producer (Agency)

[andrii-z4i]

Bug Description

When Copilot CLI 1.0.55 resumes a session created by an external producer (e.g., Agency CLI via agency cp), the new resume-auto-cd feature changes the process working directory to / instead of using the actual terminal CWD.

Current Behavior

1. User runs agency cp from ~/projects/my-repo
2. Agency creates a session file (events.jsonl) with a session.start event (no cwd field — Agency does not set it)
3. Agency launches copilot --resume <session-id> — the child process correctly inherits the terminal CWD (~/projects/my-repo)
4. Copilot 1.0.55 reads workspace.yaml (which has no CWD yet, or defaults to /) and resume-auto-cd does process.chdir("/")
5. The session.resume event is emitted with "context": { "cwd": "/" } — no git info, no branch, no repository
6. workspace.yaml is written with cwd: /
7. The session operates from / — all file operations, git detection, etc. are broken

Evidence from process log:

[DEBUG] resume-auto-cd: chdir -> /

Yet the process itself was started in the correct directory — after the chdir, remoteHosts sees / instead of the real project dir.

Expected Behavior

When resume-auto-cd finds no persisted CWD (or CWD is /), it should fall back to process.cwd() (the inherited terminal CWD) rather than changing to /. The logic should be:

1. If workspace.yaml has a valid, non-root CWD → use it (current behavior, correct)
2. If workspace.yaml has no CWD, or CWD is / or empty → stay in process.cwd() (do not chdir)
3. If COPILOT_DISABLE_RESUME_AUTO_CD=1 → skip entirely (current behavior, correct)

Regression

• Works in: Copilot CLI 1.0.51 (no resume-auto-cd feature)
• Broken in: Copilot CLI 1.0.55-0 (resume-auto-cd introduced)

Verified by comparing two sessions started 3 minutes apart in the same Agency session:

Session	Copilot Version	session.resume context
Good session	1.0.51	Full context: cwd, gitRoot, branch, repository ✅
Bad session	1.0.55	cwd: / only ❌

Steps to Reproduce

1. Create a session file manually (simulating what Agency does):

   SESSION_ID=$(uuidgen | tr "[:upper:]" "[:lower:]")
   mkdir -p ~/.copilot/session-state/$SESSION_ID
   cat > ~/.copilot/session-state/$SESSION_ID/events.jsonl << EOF
   {"type":"session.start","data":{"sessionId":"$SESSION_ID","version":1,"producer":"external","copilotVersion":"1.0.55","startTime":"2026-01-01T00:00:00.000Z"},"id":"00000000-0000-0000-0000-000000000001","timestamp":"2026-01-01T00:00:00.000Z","parentId":null}
   EOF

2. From a project directory (e.g., ~/projects/my-repo), run:

   copilot --resume $SESSION_ID

3. Observe that CWD is / instead of ~/projects/my-repo

Workaround

export COPILOT_DISABLE_RESUME_AUTO_CD=1
agency cp

Environment

• Copilot CLI: 1.0.55-0
• Agency CLI: 2026.5.23.2
• OS: macOS (arm64)

Additional Context

The resume-auto-cd feature checks workspace.yaml for a persisted CWD before the session fully initializes. When the session was created by an external producer that does not write CWD to the session metadata, workspace.yaml either does not exist yet or has a default/empty CWD — and the feature interprets this as "change to /".

This affects any external tool that creates Copilot sessions programmatically (Agency CLI, CI/CD pipelines, custom integrations) — not just direct copilot invocations.

Security Side-Effect

Because sessions resume with cwd: /, the user is prompted to trust / as a directory. If accepted, / gets added to trustedFolders in ~/.copilot/config.json, which effectively trusts the entire filesystem — a security concern.