docs(04): capture phase context and discussion log

.planning/phases/04-auth-passthrough/04-CONTEXT.md

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+# Phase 4: Auth Passthrough - Context
+
+**Gathered:** 2026-04-10
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+Mount host Claude credentials read-write into the sandbox so subscription and API key access work inside. Includes a redesign of the pre-launch env audit to show env vars, mounts, and network as three unified sections with color + prefix-based categorization.
+
+This phase does NOT scope per-project instance isolation (Phase 5) or any other `~/.claude` state (history, todos, settings).
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Credential mount
+
+- **D-01:** Mount only `~/.claude/.credentials.json` from the host — no other auth files. Other `~/.claude` contents (history, todos, settings) belong to Phase 5.
+- **D-02:** Mount read-write (already decided in v2.0 planning): OAuth token refresh writes back to `.credentials.json`; ro-bind causes silent EACCES.
+- **D-03:** If `~/.claude/.credentials.json` does not exist on the host, skip the mount silently. No warning, no error — Claude will prompt the user to log in inside the sandbox if needed.
+- **D-04:** Always mount credentials if the file exists, even when `ANTHROPIC_API_KEY` is also set. Claude Code handles precedence internally.
+
+### ANTHROPIC_API_KEY
+
+- **D-05:** `ANTHROPIC_API_KEY` is already in the host allowlist (line 204 of claudebox.sh). No additional changes needed — AUTH-02 is satisfied by existing code.
+
+### Audit screen redesign
+
+- **D-06:** Replace the current three-section audit (Sandbox-generated / Host allowlisted / Extra) with a single unified list of all env vars, each prefixed to indicate category. Add two new sections after the env list: **Mounts** and **Network**.
+- **D-07:** Prefix scheme (accessible without color — works for colorblind/screen-reader users):
+  - `[~]` — Sandbox-generated (auto-set, never from host)
+  - `[>]` — Host allowlisted (passed from host if set)
+  - `[+]` — User-configured extras (via CLAUDEBOX_EXTRA_ENV or future profile)
+- **D-08:** Color scheme mapped to prefixes:
+  - `[~]` green
+  - `[>]` yellow
+  - `[+]` cyan
+- **D-09:** Mounts section lists the active filesystem binds visible to the user — at minimum: CWD (read-write), `~/.claudebox` → `~/.claude`, and credential file if mounted. Format TBD by planner.
+- **D-10:** Network section: for now (Phase 4, before Phase 6 adds tiers), show the current default — "full (host network)". This section is a placeholder that Phase 6 will fill in.
+
+### Claude's Discretion
+
+- Exact formatting of the Mounts and Network sections (spacing, alignment, separators).
+- Whether to show a header row for each section or just a bold label.
+- Whether unset allowlisted vars are shown as `[>] VAR (not set)` or silently omitted (recommend omitting — less noise).
+
+</decisions>
+
+<canonical_refs>
+## Canonical References
+
+**Downstream agents MUST read these before planning or implementing.**
+
+### Requirements
+
+- `.planning/REQUIREMENTS.md` §Authentication (AUTH-01, AUTH-02) — credential mount spec and API key precedence rule
+
+### Existing implementation
+
+- `claudebox.sh` lines 180–263 — current ENV_ARGS construction and audit display (`print_audit` function); this is the primary code that changes
+- `claudebox.sh` lines 326–350 — bwrap exec with current mount list; credential bind goes here
+
+No external specs — requirements fully captured in decisions above and in REQUIREMENTS.md.
+
+</canonical_refs>
+
+<code_context>
+## Existing Code Insights
+
+### Reusable Assets
+
+- `ENV_ARGS` array (claudebox.sh:181) — bwrap `--setenv` args built up before exec; credential mount args follow the same pattern as a new `MOUNT_ARGS` array or inline additions to the exec call.
+- `print_audit` function (claudebox.sh:227–263) — current audit display; will be rewritten per D-06.
+- `mask_value` function (claudebox.sh:86–95) — masks sensitive var values; remains unchanged.
+- ANSI color vars (claudebox.sh:66–79) — `GREEN`, `YELLOW`, `CYAN`, `BOLD`, `RESET` already defined; `CYAN` is not yet used in the audit but is available.
+
+### Established Patterns
+
+- bwrap mount ordering matters: `~/.claudebox` bind first, then credential file bind on top of it — bwrap layers binds in order.
+- Conditional passthrough pattern: `if [[ -v "$var" ]]; then ... fi` (line 205) — same guard pattern applies for the credential file existence check: `if [[ -f "$HOME/.claude/.credentials.json" ]]; then`.
+- All user-visible output goes to stderr (`>&2`), never stdout.
+
+### Integration Points
+
+- Credential bind must be added to both the live `exec bwrap` call (line 327) AND the `--dry-run` display block (line 292) to keep them in sync.
+- `print_audit` is called before the bwrap exec and is the only place the audit display is generated.
+- `ANTHROPIC_API_KEY` already wired (line 204) — no changes needed there.
+
+</code_context>
+
+<specifics>
+## Specific Ideas
+
+- Audit format: single unified env var list with `[~]`/`[>]`/`[+]` prefixes, followed by a Mounts section and a Network section. The prefix alone (no color) must be sufficient to distinguish categories — for accessibility.
+- Network section in Phase 4 is a placeholder showing "full (host network)" — Phase 6 will make it dynamic.
+- The credential bind must be mirrored in `--dry-run` output.
+
+</specifics>
+
+<deferred>
+## Deferred Ideas
+
+- Per-project instance isolation (`~/.claude` state scoped per project) — Phase 5
+- Dynamic network tier display in audit — Phase 6 (placeholder added in Phase 4)
+- Profile-driven extra mounts shown in audit — Phase 7
+
+</deferred>
+
+---
+
+*Phase: 04-auth-passthrough*
+*Context gathered: 2026-04-10*

.planning/phases/04-auth-passthrough/04-DISCUSSION-LOG.md

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+# Phase 4: Auth Passthrough - Discussion Log
+
+> **Audit trail only.** Do not use as input to planning, research, or execution agents.
+> Decisions captured in CONTEXT.md — this log preserves the Q&A.
+
+**Date:** 2026-04-10
+**Phase:** 04-auth-passthrough
+**Mode:** discuss
+**Areas discussed:** Missing credentials fallback, Audit display, API key + OAuth coexistence, Which credential files
+
+---
+
+## Areas Discussed
+
+### Missing credentials fallback
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| What should happen if ~/.claude/.credentials.json doesn't exist on the host? | Skip silently / Warn in audit / Hard error | Skip silently |
+
+**Rationale:** No credentials = no subscription access inside sandbox. Claude will prompt to log in. No need to warn or error.
+
+---
+
+### Audit display
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| Should the credential mount appear in the pre-launch env audit? | Show in audit / Silent | Show in audit |
+
+**User input:** Requested a broader audit redesign — three sections (env, mounts, network), unified env var list with color + prefix-based categorization. Not just a minimal mount line.
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| Fold audit redesign into Phase 4 or defer? | Fold into Phase 4 / Phase 4 shows mount only | Fold into Phase 4 |
+
+**Rationale:** Phase 4 already touches the audit; doing the full redesign avoids a half-done audit screen.
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| Color scheme for unified env var list? | Green/Yellow/Cyan / Green/Yellow/Magenta / You decide | Green/Yellow/Cyan + accessibility prefixes |
+
+**User input:** Requested accessibility prefixes alongside colors: `[~]` sandbox-generated, `[>]` host allowlisted, `[+]` user-configured.
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| Prefix characters? | [S]/[H]/[U] / [~]/[>]/[+] / You decide | [~] / [>] / [+] |
+
+---
+
+### API key + OAuth coexistence
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| When ANTHROPIC_API_KEY is set, still mount credentials? | Always mount if credentials exist / Skip mount when API key is set | Always mount if credentials exist |
+
+**Rationale:** Simpler logic. Claude Code handles precedence internally.
+
+---
+
+### Which credential files
+
+| Question | Options | Selected |
+|----------|---------|----------|
+| Which auth files to mount? | .credentials.json only / Entire ~/.claude / credentials.json + .oauth-token | .credentials.json only |
+
+**Rationale:** Minimal surface. Other ~/.claude contents belong to Phase 5 (instance isolation).
+
+---
+
+## Corrections Made
+
+None — all selections were user-confirmed choices.
+
+## Scope Notes
+
+- Audit redesign (three sections, color + prefix) folded into Phase 4 scope at user request.
+- Network section in audit is a placeholder in Phase 4 — Phase 6 makes it dynamic.