# Session Log – zlh-grind

Append-only execution log for GPT-assisted development work.  
Do not rewrite or reorder past entries.

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## 2025-12-20
- Goal: Restore reliable end-to-end provisioning for devcontainers and agent-managed installs.
- Observed repeated failures during devcontainer runtime installation (node, python, go, java).
- Initial assumption was installer regression; investigation showed installers were enforcing contract correctly.
- Root cause identified: agent was not exporting required runtime environment variables (notably `RUNTIME_VERSION`).

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## 2025-12-21
- Deep dive on zlh-agent devcontainer provisioning flow.
- Confirmed that all devcontainer installers intentionally require `RUNTIME_VERSION` and fail fast if missing.
- Clarified that payload JSON is not read by installers; agent must project intent via environment variables.
- Verified that installer logic itself (artifact naming, extraction, symlink layout) was correct.

### Embedded installer execution findings
- Agent executes installers as **embedded scripts**, not filesystem paths.
- Identified critical requirement: shared installer logic (`common.sh`) and runtime installer must execute in the **same shell session**.
- Failure mode observed: `install_runtime: command not found` → caused by running runtime installer without `common.sh` loaded.
- Confirmed this explains missing runtime directories and lack of artifact downloads.

### Installer architecture changes
- Refactored installer model to:
  - `common.sh`: shared, strict, embedded-safe installation logic
  - per-runtime installers (`node`, `python`, `go`, `java`) as declarative descriptors only
- Established that runtime installers are intentionally minimal and declarative by design.
- Confirmed that this preserves existing runtime layout:
  `/opt/zlh/runtime/<language>/<version>/current`

### Artifact layout update
- Artifact naming and layout changed to simplified form:
  - `node-24.tar.xz`
  - `python-3.12.tar.xz`
  - `go-1.22.tar.gz`
  - `jdk-21.tar.gz`
- Identified mismatch between runtime name and archive prefix (notably Java).
- Introduced `ARCHIVE_PREFIX` as a runtime-level variable to resolve naming cleanly.

### Final conclusions
- No regression in installer logic; failures were execution-order and environment-projection issues.
- Correct fix is agent-side:
  - concatenate `common.sh` + runtime installer into one bash invocation
  - inject `RUNTIME_VERSION` (and related vars) into environment
- Architecture now supports deterministic, artifact-driven, embedded-safe installs.

Status: **Root cause resolved; implementation pending agent patch & installer updates.**

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