Post Edit Verification

Post-Edit Verification

After editing a component file, the natural instinct is to re-read the full file to confirm the edit landed. Don't, by default. Component JSON files are minified single-line documents, often 20–100 KB, and re-reading them after every edit consumes parent-conversation context that the actual work needs. Several lighter-weight signals do the same job — apply them in this order.

Hook-replacement context. Mitch's repo carried a PostToolUse hook (hooks/validate-component.py) that auto-blocked any Edit/Write of a tracked component suffix when the description was null/empty/>100 chars or the JSON failed to parse. The Datex Skills repo has no PostToolUse mechanism — skills are not auto-invoked by tool events. This skill is the substitute: every component-creator skill ends with "after your edit, invoke post-edit-verification", so the same two platform invariants are enforced in one place (DRY) at the skill layer instead of the harness layer. If a harness-level save-gate hook is installed in a given environment (a PostToolUse validator that blocks bad component saves), treat hook silence as a positive signal — those gates passed at the harness level — not as absent feedback; the skill checks below remain the portable floor.

Platform invariants (the minimum checks)

These two rules are non-negotiable for every component file. They are the rules the former hook enforced and they remain the floor of this skill — every invocation must confirm both, regardless of how trivial the edit looked.

1. description is present and within the platform limit. The top-level description must be non-null, non-empty, and ≤ 100 characters. The Footprint platform stores description in a SQL column capped at 100 characters; imports fail with a SQL truncation error if exceeded. See ../datex-studio-conventions/defaults.md for the canonical "Descriptions Are Mandatory" rule and ../datex-studio-conventions/file-format.md for the 100-char SQL limit. If the field is missing or too long, fix it as part of the same edit cycle — do not ask whether to backfill, just author a ≤100-char description (the user can override the wording afterward like any authored value).

2. The JSON parses cleanly. After the edit, the file must still be valid JSON. Run python -c "import json; json.load(open(r'<path>')); print('OK')". A mismatched brace, stray quote, or bad escape sequence will surface here. Free, no parent-context cost. Run it once after a sequence of edits to the same file, not after each one.

If either invariant fails, the edit is not done. Fix the violation and re-verify before claiming completion or moving on.

Verification stack (cheapest first)

1. The Edit tool's success message. The tool reports "The file ... has been updated successfully." That message means old_string matched and was replaced verbatim. If you crafted a precise old_string and the tool reported success, the textual edit is in. The remaining question is whether the result is structurally and semantically valid — which the next layers cover.

2. JSON-parse check. python -c "import json; json.load(open(r'<path>')); print('OK')". Confirms the edit didn't break the JSON envelope (mismatched braces, stray quotes, escape errors). Free, no parent-context cost. Run this once after a sequence of edits to the same file, not after each one. This is platform invariant #2.

3. Description check. After the JSON parses, confirm description is non-null, non-empty, and ≤ 100 characters:

   python -c "import json; d=json.load(open(r'<path>'))['description']; assert d and len(d) <= 100, (d, len(d) if d else 0); print('OK', len(d))"
   

   This is platform invariant #1. If the assertion trips, fix the field as part of the same edit cycle.

4. Grep with -C context. To confirm a specific edit landed where you intended, target the changed section by name, not the whole file:

   • Grep "while \(pickTasks" -C 30 returns ~60 lines around the loop instead of the entire 30 KB file.
   • Grep "concurrency_limit" -C 5 confirms an inParam was added without dumping the whole schema.
   • Order-of-magnitude context win without sacrificing precision.

5. component-validator subagent. For substantial structural validation after a non-trivial refactor — the kind of audit a final-gate review runs but file-by-file — invoke component-validator. The subagent reads the file in its own context; only the punch list comes back to the parent. For grids specifically, use grid-validator instead — it carries grid-specific gotchas (envelope shape, text-display coercion, five-location invariant) the generic dispatcher does not catch.

6. Re-read the full file (last resort). Reach for Read only when you genuinely need to see the entire structure end-to-end and don't yet know what to grep for — e.g. chasing an obscure layout issue, debugging a case where the validator's punch list was empty but something still feels wrong. Should be the last signal you reach for, not the first.

When to delegate to the component-validator agent

Delegate when:

• You finished a non-trivial edit (loop refactor, schema change, multi-step fix) on a single component file.
• The file is > 20 KB minified (most component files).
• You want a structured punch list rather than your own free-form spot-check.
• The change touched description, inParams / outParams, accessModifier, or other contract fields the type's Pre-Flight Checklist covers.

Don't delegate when:

• The edit is a single-character or single-line tweak. Grep -C is faster.
• You're mid-edit and need to decide on the next change. The parent needs the local context.
• The change is purely formatting / whitespace (validator has no rules for those).
• You already invoked the validator after a prior edit and only made small subsequent changes.

For grid files (*-grid.json), prefer grid-validator over component-validator — it is mandatory for grids regardless of edit size, because the grid-specific gotchas (envelope shape, dynamic-filter mirror drift, partial lookupcode/id syncs) are not caught by the generic dispatcher.

Risk-proportional verification

Apply verification cost in proportion to the change's risk surface. Platform invariants (#1 and #2 above) are the floor — they apply to every row. The right-hand column lists additional checks beyond the floor.

Verification is insurance, not confirmation. Match the premium to the risk — but never skip the floor.

References

• ../datex-studio-conventions/defaults.md — Canonical "Descriptions Are Mandatory" rule (non-null, non-empty, ≤ 100 chars).
• ../datex-studio-conventions/file-format.md — Canonical file-format rules including the 100-char SQL limit on description and the single-line minified-JSON convention.
• ../datex-studio-conventions/universal-checklist.md — The fuller cross-cutting checklist beyond this skill's two-invariant floor. This skill enforces the floor (description + JSON parse); component-validator walks the full list on escalation.
• component-validator — generic per-type audit dispatcher; escalation target for non-trivial edits.
• grid-validator — grid-specific audit; mandatory for *-grid.json regardless of edit size.