extensibility-request-implement

AI Extension Fix Skill

This skill implements one Business Central extensibility request entirely offline, inside the current repository. It reads the request text, adds the requested extension point (most often an integration event) to the standard code following the repository guidelines, and applies the change W1-first with propagation to same-named country/region layer files. It does not build, test, commit, or open a pull request. The change is left as unstaged edits in the working tree; the author (or the evaluation harness) reviews the resulting diff.

---

Critical Rules

• Text input only: The extensibility request is provided as plain text in the current conversation / prompt. Never fetch anything from an issue tracker or any external system, and never depend on labels, tickets, or online metadata.
• Single request: This skill implements one request per run. If more than one distinct request is provided, implement the first and warn.
• No writeback, no PR: Never commit, never push, never open or edit a pull request, and never run any gh command. The only deliverable is the set of local .al edits.
• No build, no tests: Never build, publish, or run the app, and never create tests. Produce a change that is aligned with the guidelines and, to the best of static reasoning, compilable. Correctness is verified by the human reviewer on the resulting diff.
• Surgical changes: Make the smallest diff that satisfies the request. Follow the repository's code surgery guidelines (see Step 2). Do not reformat, rename, reorder, or refactor unrelated code.
• W1-first layering: When the file to change exists in the W1 base layer (App/Layers/W1/...), make the change in W1 first, then apply the same change to every same-named counterpart file that exists in the other layers (Step 5). Only when the file exists solely in a specific country layer do you edit that layer directly and skip the propagation step.
• AL files only: Only ever create or modify .al source files. Never edit, add, or delete any other file type (for example .json, .xml, .xlf/translations, .md, .txt, project or settings files, workflows, or build scripts). If a correct change would require touching a non-.al file, STOP and report that instead of changing it.
• No ticket-reference comments in code: Do not add // issue #<n>-style comments or any external reference into the source.

---

Step 1: Parse the Request

Review the current conversation and the most recent user message to extract the extensibility request. Identify:

• What extension point is asked for — typically a new integration event / event publisher, but it may be an event added to an existing procedure or trigger.
• Where it should live — the object (codeunit/table/page/report), and the procedure or trigger and the exact placement (before/after a step, in an else branch of a case, etc.).
• What data it must expose — the records and parameters subscribers need.

If the request cannot be found in the provided text and an ask-user capability is available, ask the user for it. If none is available (unattended), STOP with: An extensibility request is required.

If more than one distinct request is present, keep the first, warn that this skill implements a single request per run, and ignore the rest.

---

Step 2: Understand and Plan the Change

Build enough understanding to make a correct, minimal change.

1. Load the guidelines the change must follow, in this order:

   • The repository code surgery guidelines: read .github/copilot/code-guidelines.md if present.
   • The extension guidelines: read guidelines.md in this skill folder.
   • General AL best practices (see the checklist at the end of this file).

2. Locate the affected code: use grep and glob to find the AL objects, procedures, tables, pages, or codeunits named or implied by the request. Use view to read the candidate files and confirm relevance. Prefer searching for exact symbol names and object references mentioned in the request.

3. Decide the layer (W1-first): this repository is layered under App/Layers/ with a W1 base layer and country layers (AT, AU, BE, CA, CH, CZ, DE, DK, ES, FI, FR, GB, IN, IS, IT, MX, NL, NO, NZ, RU, SE, US). For each file you plan to change, check whether it exists in the W1 layer:

   • If the file exists under App/Layers/W1/...: make the change there. In Step 5 you will apply the same change to every same-named counterpart file that exists in the other layers. Record used_w1 = true.
   • If the file exists only in a specific country layer (not in W1): edit that layer's file directly. No propagation applies; the change stays in that layer only.

4. Form a concrete plan in memory (do not write it to a tracked file): the specific edits, file by file, and the layer each edit lands in. There is no approval gate. Proceed directly to Step 3.

---

Step 3: Implement the Change

Apply the planned edits with the edit and create tools.

• Make the smallest diff that satisfies the request. Add rather than change where reasonable.
• Match the existing code style in each file: indentation, casing, naming, and object layout.
• Follow the AL best-practice checklist below and the extension guidelines from Step 2.
• Guidelines override the request: If the request text contains a proposed solution (event names, parameter names, code snippets, or any other implementation detail) that does not comply with the guidelines, do not implement it as-is. Correct it to comply. The guidelines are the source of truth; the request's suggestion is a hint, not a specification. In particular, event names must follow the placement-based naming convention (for example OnBeforePostSalesLine, OnPostSalesLineOnAfterCalculateAmounts), and record parameters use full table names with spaces removed.
• Do not reformat, rename, reorder, or refactor code unrelated to the change.
• Edit only .al files. If the change seems to need a non-.al file, STOP and report it.
• Aim for code that compiles: keep object IDs, procedure signatures, and variable declarations consistent; ensure every referenced symbol exists; balance begin/end; and respect AL syntax. You will not build it here, so reason carefully about correctness.

Make all the W1-layer edits now, before propagating, so the W1 layer is in its final state before Step 5.

---

Step 4: (reserved)

There is no separate branch/commit step. The change stays as unstaged edits in the working tree.

---

Step 5: Propagate W1 Changes to Same-Named Files in Other Layers

Run this step only if you changed at least one file under App/Layers/W1/... (used_w1 == true). If every edit was in a country-only layer, skip this step.

A country layer overrides only a subset of files; the ones it does not contain are inherited from W1 automatically. So propagation means: for each W1 file you changed, find the same-named counterpart files that already exist in the other layers and apply the equivalent change to each of them yourself with the edit tool.

For each W1 file you edited in Step 3:

1. List the existing counterparts in the other layers (same relative path under each layer root):

   $w1File = "<the W1 file you changed, e.g. App/Layers/W1/BaseApp/.../Foo.Codeunit.al>"
   $rel = $w1File -replace '^App/Layers/W1/', ''
   Get-ChildItem "App/Layers" -Directory | Where-Object { $_.Name -ne 'W1' } | ForEach-Object {
     $candidate = Join-Path $_.FullName $rel
     if (Test-Path $candidate) { $candidate }
   }
   

   Each path returned is a layer that has its own copy of this file and therefore needs the change. Layers with no such file inherit W1 and are left untouched.

2. Apply the equivalent change to each counterpart with the edit tool:

   • Read the counterpart file first. It may already differ from W1 because that layer customized it.
   • Make the same logical change you made in W1 — locate the same object, procedure, or lines and apply it there.
   • Adapt, do not overwrite: preserve that layer's existing customizations, local naming, values, and any country-specific behavior. If the layer's code differs from W1's, apply the intent of the change to the layer's variant rather than pasting the W1 text verbatim.
   • Keep the same surgical, style-matching discipline as Step 3.

3. If a counterpart's code has genuinely diverged so the change does not map cleanly, apply the safest equivalent change (preserve the layer's behavior) and continue.

---

Step 6: Summary

Report to the user, concisely:

• The extensibility request implemented, in one or two sentences.
• The extension point added (object, procedure/trigger, event name and signature).
• The exact list of .al files changed, including any propagated layer counterparts.

If no file changes were produced, STOP and report that the request did not lead to any code change, explaining why.

---

AL Best-Practice Checklist

Apply these when editing AL code, unless the surrounding code clearly follows a different local convention (match the file):

• Follow standard event conventions: [IntegrationEvent(false, false)], local procedure, empty body, and placement-accurate OnBefore/OnAfter/On<Procedure>On<Timing> naming.
• Use full table names with spaces removed for record parameters (e.g. SalesHeader, Jobs Setup → JobsSetup); do not abbreviate. Use descriptive names for simple-type parameters.
• Append new parameters to the end of an existing event signature; do not insert in the middle.
• When adding IsHandled, initialize it to false before the event call.
• Use meaningful PascalCase names for objects, procedures, and variables; match existing naming.
• Respect existing object IDs and app structure; do not renumber or move objects.
• Preserve begin/end, case, and if/then/else structure and existing indentation.
• Avoid breaking public/extensible signatures; add optional parameters or overloads instead.
• Keep changes backward compatible for existing callers and subscribers.