Implementation Plan: T5-P6-A2-WP1 Close Test Gap for config.toml auto_compact_limit Override + ADR

docs/decisions/0004-recipe-redelivery.md

@@ -0,0 +1,48 @@
+# ADR-0004: Codex Recipe Knowledge Re-Delivery via load_recipe
+
+**Status:** Accepted
+**Date:** 2026-06-27
+**Issue:** [#4051](https://github.com/TalonT-Org/AutoSkillit/issues/4051)
+
+## Context
+
+Codex auto-compaction fires at 90% of the 258K context window. When triggered, it can
+destroy recipe content delivered by `open_kitchen` in the initial orchestrator response.
+After compaction, the agent loses the recipe steps it needs to complete the pipeline.
+
+Two defenses exist:
+
+1. **Primary — disable compaction**: `ensure_codex_mcp_registered` writes
+   `model_auto_compact_token_limit = 999_999_999` (an unreachable threshold) to
+   `~/.codex/config.toml`. `setup_session_dir` copies this config into each session
+   directory, ensuring every headless session inherits the setting.
+
+2. **Guard — block raw recipe reads**: The `recipe_read_guard.py` PreToolUse hook
+   blocks `run_cmd`/`Bash` from reading recipe YAML, SKILL.md, or agent definition
+   files, and blocks `run_python` from calling `autoskillit.recipe.*` callables.
+   This prevents the agent from self-recovering from compaction loss via raw file
+   access — compaction loss is treated as a hard failure, not a recoverable state.
+
+If the primary defense is ever relaxed (e.g., Codex fixes its compaction behavior or
+the context window grows), the agent needs a sanctioned channel to re-acquire recipe
+knowledge without reading raw files.
+
+## Decision
+
+> **`load_recipe` (the MCP tool exposed by `server/tools/tools_recipe.py`) is the
+> sanctioned channel for recipe knowledge re-delivery after context compaction.**
+
+If recipe content is lost, the agent must call `load_recipe` to re-acquire it. The
+`recipe_read_guard` enforces that only this path is allowed — raw file access is denied.
+
+This is a forward obligation: when the primary defense (unreachable auto-compact limit)
+is relaxed, `load_recipe` re-delivery must be tested end-to-end as the recovery path.
+
+## Consequences
+
+- `recipe_read_guard.py` error messages direct the agent to call `load_recipe`.
+- No production code changes are needed today — the channel already exists and works.
+- Future work relaxing `CODEX_AUTO_COMPACT_LIMIT` must add integration tests verifying
+  `load_recipe` re-delivery restores full pipeline execution capability.
+- `test_copied_config_has_auto_compact_limit` validates the primary defense path:
+  `setup_session_dir` preserves the override in the copied `config.toml`.

docs/decisions/README.md

@@ -3,3 +3,4 @@
 - [0001-prohibit-background-subagent-execution.md](0001-prohibit-background-subagent-execution.md) — prohibit `run_in_background: true` in all skills
 - [0002-ban-inline-shell-scripts-from-cmd.md](0002-ban-inline-shell-scripts-from-cmd.md) — Prohibit inline shell scripts in recipe cmd fields; require externalization to .sh files or run_python callables
 - [0003-skill-args.md](0003-skill-args.md) — Pass skill inputs as positional arguments, not environment variables
+- [0004-recipe-redelivery.md](0004-recipe-redelivery.md) — Sanctioned `load_recipe` channel for recipe knowledge re-delivery after Codex context compaction

tests/execution/backends/test_codex_backend.py

@@ -1753,3 +1753,26 @@ def test_no_git_subdir_created(self) -> None:
         self._write_all_source_files()
         CodexBackend().setup_session_dir(self.session_dir)
         assert not (self.session_dir / ".git").exists()
+
+    def test_copied_config_has_auto_compact_limit(self) -> None:
+        import tomllib
+
+        from autoskillit.execution.backends import CODEX_AUTO_COMPACT_LIMIT
+
+        (self.codex_home / "config.toml").write_text(
+            f"model_auto_compact_token_limit = {CODEX_AUTO_COMPACT_LIMIT}\n"
+            "[mcp_servers.autoskillit]\n"
+        )
+        (self.codex_home / "auth.json").write_text("{}")
+        CodexBackend().setup_session_dir(self.session_dir)
+        data = tomllib.loads((self.session_dir / "config.toml").read_text(encoding="utf-8"))
+        assert data["model_auto_compact_token_limit"] == CODEX_AUTO_COMPACT_LIMIT
+
+    def test_session_config_lacks_key_when_source_lacks_it(self) -> None:
+        import tomllib
+
+        (self.codex_home / "config.toml").write_text("[mcp_servers.autoskillit]\n")
+        (self.codex_home / "auth.json").write_text("{}")
+        CodexBackend().setup_session_dir(self.session_dir)
+        data = tomllib.loads((self.session_dir / "config.toml").read_text(encoding="utf-8"))
+        assert "model_auto_compact_token_limit" not in data