---
id: TASK-18.1
title: 'Add code annotations for zconf ${key} interpolation behavior'
status: Done
assignee:
  - codex
created_date: '2026-02-19 17:45'
updated_date: '2026-02-19 17:47'
labels: []
dependencies: []
references:
  - lua/zync/lib/utils.lua
  - lua/zync/api/configurator.lua
  - lua/zync/api/configurator/sandbox.lua
parent_task_id: TASK-18
---

## Description

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Add/expand inline comments and LuaDoc annotations around interpolation utilities and configurator application points to document behavior and scope.
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## Acceptance Criteria
<!-- AC:BEGIN -->
- [x] #1 Update lua/zync/lib/utils.lua with comments describing interpolate/interpolate_recursive behavior, recursion, missing keys, and cycle handling.
- [x] #2 Update lua/zync/api/configurator.lua with comments explaining when interpolation runs and how profile-scoped values are used.
- [x] #3 Update schema/notes in lua/zync/api/configurator/sandbox.lua if needed to mention supported keys for interpolation.
<!-- AC:END -->

## Implementation Notes

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Added inline comments/LuaDoc notes in utils interpolation helpers, configurator interpolation flow, and sandbox schema note about allowed top-level keys and interpolation scope. Tests not run (docs-only change).
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## Final Summary

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Summary:
- Documented interpolation behavior in utils (missing keys, cycles, type handling) and configurator (top-level vs profile-scoped interpolation).
- Added schema note clarifying interpolation scope within allowed top-level keys.

Tests:
- Not run (documentation-only changes)

Notes:
- No Definition of Done items were defined for this task.
<!-- SECTION:FINAL_SUMMARY:END -->
