AEM as a Cloud Service — Code Migration

Source → target: Legacy AEM 6.x / AMS / on-prem → AEM as a Cloud Service. Scoped under skills/aem/cloud-service/skills/migration/ so this is not confused with Edge Delivery or 6.5 LTS.

This skill is orchestration: BPA data, CAM/MCP, one pattern per session, and target discovery. Transformation rules and steps live in the best-practices skill — read that skill and the right references/*.md before editing code.

Setup: Use the aem-cloud-service install (see repository root README) so both migration and best-practices paths are available. If you already have the monorepo open with resolvable {best-practices} paths, no separate install step is required.

Quick start (for the person driving the agent)

One pattern per chat/session — if you ask to "fix everything," the skill will ask you to pick first (e.g. scheduler vs replication vs htlLint).

You have…	Say something like…	What happens
A BPA CSV	"Fix scheduler findings using ./path/to/bpa.csv"	Fastest path: CSV → cached collection → files
CAM + MCP only	"Get scheduler findings from CAM; I'll pick the project when you list them."	Agent lists projects → you confirm → MCP fetch (cam-mcp.md)
Just a few files	"Migrate scheduler in core/.../MyJob.java"	Manual flow: no BPA required
OSGi → Cloud Manager	"Scan my config files and create Cloud Manager environment secrets or variables."	Agent auto-reads references/osgi-cfg-json-cloud-manager.md (full Adobe-aligned rules inlined there); no BPA pattern id
HTL lint warnings	"Fix htlLint issues in ui.apps"	Proactive discovery via rg → fix per reference module

Starter prompts (copy-paste):

• "Use the migration skill: scheduler only, BPA CSV at ./reports/bpa.csv, then apply best-practices reference modules before editing."
• "Replication only from CAM; list projects first, I'll pick one."
• "Manual: event listener migration for .../Listener.java — read best-practices module first."
• "Scan my config files and create Cloud Manager environment secrets or variables."
• "Fix htlLint in ui.apps — scan for data-sly-test redundant constant warnings and fix them."

Path convention (Adobe Skills monorepo)

From the repository root (parent of the skills/ directory):

Symbol	Path
{best-practices}	skills/aem/cloud-service/skills/best-practices/

Examples: {best-practices}/SKILL.md, {best-practices}/references/scheduler.md.

Workspace scope (IDE) — user code only

Applies to finding and editing the user's AEM project (Java, bundles, config, HTL), not to reading installed skill files under {best-practices}.

• Treat the current IDE workspace root folder(s) (single- or multi-root) as the only boundary for searches, globs, grep, and file reads/writes for migration targets.
• Do not search parent directories, sibling folders on disk, ~, other clones, or arbitrary absolute paths to "discover" sources unless the user explicitly names those paths or asks you to include them.
• BPA CSV / CAM targets: If a filePath or class-to-file mapping does not resolve under a workspace root, stop and tell the user which paths are missing — do not hunt elsewhere on the filesystem. Ask them to open the correct project in the IDE or adjust paths.
• Manual flow: Only migrate files the user named that live under the workspace (or paths they explicitly provided). Do not expand scope by searching outside the workspace.

Required delegation (do this first)

Branch A — OSGi configs → Cloud Manager (no Java BPA pattern this session): If the user asks to scan config files, create / set up Cloud Manager environment secrets or variables, move passwords or secrets out of OSGi / .cfg.json / ui.config, or mentions $[secret:] / $[env:] for AEM CS, then read references/osgi-cfg-json-cloud-manager.md immediately and follow the product rules and workflow defined in that file (Adobe AEM as a Cloud Service OSGi + Cloud Manager behavior is reproduced there—no external doc URL required). Sleek prompts are enough — no need to name the reference file. Skip branch B for that work.

Branch B — Java / HTL / BPA pattern migration:

1. Read {best-practices}/SKILL.md — critical rules, Java baseline links, Pattern Reference Modules table, Manual Pattern Hints.
2. Read {best-practices}/references/<module>.md for the single active pattern (see table in that SKILL.md).
3. When code uses SCR, ResourceResolver, or console logging, read {best-practices}/references/scr-to-osgi-ds.md and {best-practices}/references/resource-resolver-logging.md (or the hub {best-practices}/references/aem-cloud-service-pattern-prerequisites.md).

Do not transform Java or HTL until the pattern module is read (branch B). Branch A does not require {best-practices} pattern modules.

When to Use This Skill

• Migrate legacy AEM Java toward Cloud Service–compatible patterns
• Fix HTL (Sightly) lint warnings (data-sly-test: redundant constant value comparison) across component templates
• Drive work from BPA (CSV or cached collection) or CAM via MCP
• Enforce one pattern type per session
• OSGi → Cloud Manager: Branch A — scan scoped .cfg.json, apply $[secret:…] / $[env:…] per rules in references/osgi-cfg-json-cloud-manager.md; gitignored handoff; no secret values in chat.

OSGi configs and Cloud Manager (no BPA pattern id)

Sleek user prompts are enough (see Quick start). Agent: Branch A → read the reference → One-prompt workflow; obey the inlined Adobe AEM CS rules in that file (value types, placeholders, CM API/CLI, custom-properties-only, repoinit, runmode context, local SDK secrets). Ambiguous or Adobe-owned PIDs → needs_user_review, not guesses.

Prerequisites

• Project source and Maven/Gradle build
• BPA CSV or MCP access optional but recommended
• For htlLint: ui.apps or equivalent content package with .html HTL templates

BPA findings — flow

Scripts run via getBpaFindings (see Calling the helper); do not reimplement collection logic by hand unless the helper is unavailable.

The helper has two independent paths, chosen by what the caller configures:

1. MCP configured (mcpFetcher + projectId passed) → first call fetches all findings from MCP and caches them to <collectionsDir>/mcp/<projectId>/<pattern>.json. Every call (first and subsequent) reads from the MCP cache and returns one batch.
2. MCP not configured, BPA CSV provided → first call parses the CSV and writes the unified-collection JSON to <collectionsDir>/unified-collection.json. Every call reads from the CSV cache and returns one batch.

The two caches are disjoint — MCP sessions and CSV sessions never shadow each other. If neither is configured, the helper reports no-source and the agent asks for one.

Batching is mandatory on every path. getBpaFindings returns findings in batches of 5 by default with a paging envelope:

result.targets   // this batch (length <= limit)
result.paging    // { total, returned, offset, limit, nextOffset, hasMore }

Process one batch at a time; stop after each batch and report progress to the user; resume on the user's go-ahead by re-calling the helper with offset: paging.nextOffset. See Batched processing (batch size 5) below.

Note: htlLint does not appear in BPA CSV — it uses proactive rg discovery instead. See htlLint flow below.

CAM via MCP (summary)

Use fetch-cam-bpa-findings only after list-projects and explicit user confirmation of which project row to use (prefer projectId from that list). Do not pass an unconfirmed project name string. Full tool schemas, REST notes, retries, and error handling: references/cam-mcp.md.

What the user might say

• "Fix scheduler using ./reports/bpa.csv" → CSV path known
• "Fix scheduler" → collection → MCP → ask for CSV
• "Migrate core/.../Foo.java" → manual flow
• "Fix htlLint in ui.apps" → proactive discovery flow

Calling the helper

Scripts live under ./scripts/ (next to this SKILL.md).

const { getBpaFindings } = require('./scripts/bpa-findings-helper.js');

// First batch (defaults: limit=5, offset=0)
const result = await getBpaFindings(pattern, {
  bpaFilePath: './cleaned_file6.csv',
  collectionsDir: './unified-collections',
  projectId: '...',
  mcpFetcher: mcpFunction
  // limit: 5,   // implicit default
  // offset: 0,  // implicit default
});

// Next batch — only after the user says to continue
if (result.paging?.hasMore) {
  const next = await getBpaFindings(pattern, {
    bpaFilePath: './cleaned_file6.csv',
    collectionsDir: './unified-collections',
    projectId: '...',
    mcpFetcher: mcpFunction,
    offset: result.paging.nextOffset
  });
}

result:

• success, source ('unified-collection' | 'bpa-file' | 'mcp-server' | …)
• message (includes a human-readable batch status)
• targets — the current batch (length <= limit)
• paging: { total, returned, offset, limit, nextOffset, hasMore } — always present on successful calls

To disable batching for a one-off programmatic caller, pass limit: null. The skill workflow itself never does this.

Collection caching

Collections live under ./unified-collections/. If a collection exists and the user supplies a new CSV, ask whether to reuse or re-process.

Reading a BPA CSV

Filter rows where pattern matches the session pattern. Typical columns: pattern, filePath, message.

MCP errors and fallback

Critical: On MCP failure, stop the workflow immediately and give the user the exact tool error message (verbatim), including "not found" / 404-style project errors. Do not continue with migration steps, infer a different CAM project from the workspace, or switch to manual/local migration on your own.

Exception: enablement restriction errors (prefix documented in references/cam-mcp.md) must be shown verbatim with no paraphrase and no automatic fallback until the user addresses them.

After stopping, you may summarize what failed in plain language and, if helpful, re-show projects from list-projects. Only continue when the user explicitly directs the next step (e.g. correct project id/name from the list, BPA CSV path, or specific Java files for manual flow).

For retries, error categories, and when user-directed CSV/manual paths are allowed, follow references/cam-mcp.md; still no silent fallback. Never hide tool errors from the user.

Optional prompt after stop (user must reply): "Reply with the CAM project to use (id or name from the list), a path to your BPA CSV, or the Java files for a manual migration."

Pattern modules

Do not duplicate the pattern table here. Use {best-practices}/SKILL.md → Pattern Reference Modules (references/<file>.md).

Workflow

One pattern per session

If the user asks to fix everything or BPA mixes patterns, ask which pattern first. Prefer one commit per pattern session.

Step 1: Pattern id

If the request is OSGi configs → Cloud Manager (see Required delegation, branch A), do not map to a BPA pattern — follow references/osgi-cfg-json-cloud-manager.md instead.

Otherwise map the request to a pattern id: scheduler, resourceChangeListener, replication, eventListener, eventHandler, assetApi, htlLint. If unclear, use Manual Pattern Hints in {best-practices}/SKILL.md or ask the user to pick one of those.

Step 2: Availability

If the id is missing from the best-practices table, say the pattern is not supported yet.

Step 3: Targets

For BPA patterns (scheduler, resourceChangeListener, replication, eventListener, eventHandler, assetApi): Run getBpaFindings (with bpaFilePath when provided). Internally: cache → CSV → MCP → manual only when each step is applicable and succeeds; if MCP fails, obey MCP errors and fallback (stop; no silent chain). For MCP details, references/cam-mcp.md.

getBpaFindings returns a batch of 5 findings (default limit=5) along with a paging envelope. The agent processes that batch only; it does not request the next batch until the user says to continue. See Batched processing (batch size 5) below.

For htlLint: Skip BPA/CSV/MCP — targets come from proactive rg discovery. See htlLint flow below.

Step 4: Read before edits

STOP. Read {best-practices}/SKILL.md and {best-practices}/references/<module>.md for the active pattern.

Step 5: Process the batch

For each finding in the returned batch only (up to 5):

1. Resolve the target inside the IDE workspace (see Workspace scope (IDE)).
2. Read source → classify with the module → apply steps in order → check lints → next file.

Do not request the next batch mid-processing. Never hold more than one batch of findings in working memory at a time.

Step 6: Report batch and wait

After finishing the batch, summarise for this batch only:

• paging.returned findings processed (of paging.total), with class names.
• Any files touched, plus any skips / failures.
• If paging.hasMore === true, tell the user: "Processed batch of N (offset {offset}–{offset + returned − 1} of {total}). Reply continue to process the next batch, or name specific classes to focus on."
• If paging.hasMore === false, say the pattern is done and move to the overall session report.

Stop and wait for the user. Do not automatically start the next batch. Only call getBpaFindings (or fetch-cam-bpa-findings) again when the user explicitly requests it, and pass offset: paging.nextOffset unchanged.

Manual flow (no BPA)

User-named files → classify (best-practices hints or ask) → confirm module exists → read {best-practices}/SKILL.md + module → transform → report.

OSGi → Cloud Manager flow

Does not use BPA CSV, CAM/MCP, or best-practices pattern modules for collection. Follow Branch A in Required delegation and the One-prompt workflow in references/osgi-cfg-json-cloud-manager.md.

htlLint flow

htlLint does not use BPA CSV or CAM/MCP. Instead:

1. Read {best-practices}/references/data-sly-test-redundant-constant.md — it contains the Workflow, Proactive Discovery rg patterns, and all 4 fix patterns.
2. Discover targets using the rg commands from the module's Proactive Discovery table (scope: ui.apps/**/jcr_root/**/*.html or the user's content package paths).
3. Group hits by file, classify each by pattern (boolean literal, raw string, numeric, split expression).
4. Fix each hit per the matching pattern section in the module.
5. Report and recommend the user run mvn clean install or HTL validate to confirm no warnings remain.

Batched processing (batch size 5)

Findings are served to the agent in batches of 5 by default, regardless of source (MCP or CSV). Batching happens client-side — the heavy fetch (MCP call or CSV parse) happens once and is materialized to a local JSON cache; every subsequent batch is a cheap slice of that cache.

Rules

1. Default limit is 5. Pass limit: 5 (or accept the helper default). The skill never requests a larger batch unless the user has explicitly asked for one.
2. Offset starts at 0 and advances by result.paging.nextOffset from the previous call. Do not compute offsets from offset + limit — read nextOffset from the previous response; it is authoritative.
3. Stable ordering. Each cache file is written once with a deterministic order; every slice from it is therefore stable and contiguous.
4. One batch per call. One batch in memory at a time. Process, report, stop. No pre-fetching, no merging across batches.
5. Resume is stateless. The skill does not maintain its own progress file. Resuming means "call the helper again with offset: previous.paging.nextOffset". If the session ends, a later session calls with the same pattern and offset and gets the same batch.
6. Done when paging.hasMore === false (or paging.nextOffset === null).
7. To refresh source data, delete the relevant cache file:
   • CSV: <collectionsDir>/unified-collection.json
   • MCP: <collectionsDir>/mcp/<projectId>/<pattern>.json

Agent-visible flow (CSV path)

[User] "Fix scheduler findings using ./reports/bpa.csv"
[Agent] getBpaFindings('scheduler', { bpaFilePath, limit: 5, offset: 0 })
        // first call parses CSV → writes <dir>/unified-collection.json → slices
        → paging: { total: 137, returned: 5, offset: 0, nextOffset: 5, hasMore: true }
        Processes 5 findings.
        Reports: "Processed 5 of 137 (offset 0–4). Reply `continue` for the next batch."
[User] "continue"
[Agent] getBpaFindings('scheduler', { bpaFilePath, limit: 5, offset: 5 })
        // reads cached JSON — no CSV re-parse
        → paging: { ..., offset: 5, nextOffset: 10, hasMore: true }
        Processes next 5.
...

Agent-visible flow (MCP path)

[User] "Fix scheduler findings from CAM project <id>"
[Agent] getBpaFindings('scheduler', { mcpFetcher, projectId, limit: 5, offset: 0 })
        // first call: one MCP fetch → writes <dir>/mcp/<projectId>/scheduler.json → slices
        → paging: { total: 137, returned: 5, offset: 0, nextOffset: 5, hasMore: true }
        Processes 5 findings.
        Reports and stops.
[User] "continue"
[Agent] getBpaFindings('scheduler', { mcpFetcher, projectId, limit: 5, offset: 5 })
        // reads cached MCP JSON — NO additional MCP call
        → paging: { ..., offset: 5, nextOffset: 10, hasMore: true }
...

Do not

• Do not call getBpaFindings with limit: null inside the skill flow. That option exists only for programmatic callers that deliberately want the full list.
• Do not invent a next batch offset. Always read paging.nextOffset from the previous response.
• Do not accumulate targets across batches in memory.
• Do not call the MCP tool for every batch; the first call caches, subsequent batches read the cache.

Quick reference

Source priority (when choosing how to obtain targets): unified collection → BPA CSV → MCP → manual paths. Not an automatic cascade after MCP errors — if MCP fails, stop and wait for user direction (see MCP errors and fallback). For htlLint, use proactive rg discovery (no BPA/MCP). For OSGi → Cloud Manager, use references/osgi-cfg-json-cloud-manager.md only (no BPA/MCP).

Batch size: 5 (default) on every BPA source. See Batched processing above.

User-facing snippets: "Using existing BPA collection (N findings)…" / "Processing your BPA report…" / "Fetched findings from CAM." / "Scanning HTL templates for data-sly-test lint issues…" / optional prompt after MCP stop above.

CLI (development only)

From this skill's directory:

# First batch (default offset=0, limit=5)
node scripts/bpa-findings-helper.js scheduler ./unified-collections
node scripts/bpa-findings-helper.js scheduler ./unified-collections ./cleaned_file6.csv

# Next batch: offset=5, limit=5
node scripts/bpa-findings-helper.js scheduler ./unified-collections ./cleaned_file6.csv 5 5

# Full unbounded listing (development / debugging only — skill never does this)
node scripts/bpa-findings-helper.js scheduler ./unified-collections ./cleaned_file6.csv 0 all

# Same batching on the low-level reader
node scripts/unified-collection-reader.js all ./unified-collections 0 5