feat(ce-work-beta): add beta Codex delegation mode (#476)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

plugins/compound-engineering/AGENTS.md

@@ -136,7 +136,8 @@ Why: shell-heavy exploration causes avoidable permission prompts in sub-agent wo
 
 - [ ] Never instruct agents to use `find`, `ls`, `cat`, `head`, `tail`, `grep`, `rg`, `wc`, or `tree` through a shell for routine file discovery, content search, or file reading
 - [ ] Describe tools by capability class with platform hints — e.g., "Use the native file-search/glob tool (e.g., Glob in Claude Code)" — not by Claude Code-specific tool names alone
-- [ ] When shell is the only option (e.g., `ast-grep`, `bundle show`, git commands), instruct one simple command at a time — no chaining (`&&`, `||`, `;`) and no error suppression (`2>/dev/null`, `|| true`). Simple pipes (e.g., `| jq .field`) and output redirection (e.g., `> file`) are acceptable when they don't obscure failures. **Exception:** `!` backtick pre-resolution commands may use error suppression and `||` fallbacks to produce clean sentinel values (e.g., `|| echo '__FAILED__'`), since these run at load time and the model needs a parseable signal, not raw stderr
+- [ ] When shell is the only option (e.g., `ast-grep`, `bundle show`, git commands), instruct one simple command at a time — no action chaining (`cmd1 && cmd2`, `cmd1 ; cmd2`) and no error suppression (`2>/dev/null`, `|| true`). Boolean conditions within if/while guards (`[ -n "$X" ] || [ -n "$Y" ]`) are fine — that is normal conditional logic, not action chaining. Simple pipes (e.g., `| jq .field`) and output redirection (e.g., `> file`) are acceptable when they don't obscure failures
+- [ ] **Pre-resolution exception:** `!` backtick pre-resolution commands run at skill load time, not at agent runtime. They may use chaining (`&&`, `||`), error suppression (`2>/dev/null`), and fallback sentinels (e.g., `|| echo '__NO_CONFIG__'`) to produce a clean, parseable value for the model. This is the preferred pattern for environment probes (CLI availability, config file reads) that would otherwise require runtime shell calls with chaining. Example: `` !`command -v codex >/dev/null 2>&1 && echo "AVAILABLE" || echo "NOT_FOUND"` ``
 - [ ] Do not encode shell recipes for routine exploration when native tools can do the job; encode intent and preferred tool classes instead
 - [ ] For shell-only workflows (e.g., `gh`, `git`, `bundle show`, project CLIs), explicit command examples are acceptable when they are simple, task-scoped, and not chained together
 
@@ -148,6 +149,20 @@ When a skill orchestrates sub-agents that need codebase reference material, pref
 
 When dispatching sub-agents, **omit the `mode` parameter** on the Agent/Task tool call unless the skill explicitly needs a specific mode (e.g., `mode: "plan"` for plan-approval workflows). Passing `mode: "auto"` or any other value overrides the user's configured permission settings (e.g., `bypassPermissions` in their user-level config), which is never the intended behavior for routine subagent dispatch. Omitting `mode` lets the user's own `defaultMode` setting apply.
 
+### Reading Config Files from Skills
+
+Plugin config lives at `.compound-engineering/config.local.yaml` in the repo root. This file is gitignored (machine-local settings), which creates two gotchas:
+
+1. **Path resolution:** Never read the config relative to CWD — the user may invoke a skill from a subdirectory. Always resolve from the repo root. In pre-resolution commands, use `git rev-parse --show-toplevel` to find the root.
+
+2. **Worktrees:** Gitignored files are per-worktree. A config file created in the main checkout does not exist in worktrees. When reading config, fall back to the main repo root if the file is missing in the current worktree:
+   ```
+   !`cat "$(git rev-parse --show-toplevel 2>/dev/null)/.compound-engineering/config.local.yaml" 2>/dev/null || cat "$(dirname "$(git rev-parse --path-format=absolute --git-common-dir 2>/dev/null)")/.compound-engineering/config.local.yaml" 2>/dev/null || echo '__NO_CONFIG__'`
+   ```
+   The first `cat` tries the current worktree root. The second derives the main repo root from `git-common-dir` as a fallback. In a regular (non-worktree) checkout, both paths are identical.
+
+If neither path has the file, fall through to defaults — never fail or block on missing config.
+
 ### Quick Validation Command
 
 ```bash