Legacy Code Documentation

Produce documentation for ABAP objects that have none. The output is for two audiences at once: a developer who must change the code next month, and a manager deciding whether it survives the next migration.

Prerequisites

• sap-adt-mcp ≥ 0.8.1 connected to the target system (adt_ping to verify).
• NetWeaver 7.4x+ — only core ADT read endpoints are needed (source read,

search, where-used). adt_read_table examples additionally need NW 7.55+; skip data sampling on older systems.

• SAP user authorizations: repository display only (S_DEVELOP display).
• Read-only mode: fully supported — this skill never writes to SAP. (It may

write the documentation to a local file if the user asks.)

• Large sources: adt_get_source output is capped per call (~64 KB). For

big programs paginate with firstLine/lastLine, or slice with onlyMethod. Never assume one call returned the whole object — check truncated/totalLines.

Workflow

1. Scope the object

adt_search_objects if only a fuzzy name is known. Identify the object type — the strategy differs:

• Program (PROG): fetch the main source, then list its includes

(adt_browse_package on its package, or INCLUDE statements from source) and fetch each include that carries logic.

• Class (CLAS): fetch definitions first (the public contract), then

implementations method by method (onlyMethod) for the ones that matter.

• Function group (FUGR): document each function module separately

(adt_get_source with type function + group); shared TOP include for state.

2. Read with a checklist

While reading, collect — don't paraphrase line by line:

• Entry points: events (START-OF-SELECTION, user-commands), public

methods, FM interfaces, selection screen parameters.

• Database touchpoints: every table read (SELECT/JOIN) and **especially

every write** (INSERT/UPDATE/MODIFY/DELETE, CALL FUNCTION ... IN UPDATE TASK). Writes are the risk register.

• External calls: RFCs, BAPIs, file I/O (OPEN DATASET, GUI_*), HTTP,

authority-checks, COMMIT/ROLLBACK placement.

• Configuration coupling: hardcoded values, TVARV/Z-config table reads,

sy-mandt/sy-sysid branching.

• Smells worth flagging: SELECT in loops, missing authority checks before

writes, swallowed exceptions, dead branches (adt_grep_source across the package helps find copy-paste siblings).

3. Map the blast radius

• adt_where_used on the main object: who calls this? A "legacy" report

called by 14 other programs is infrastructure, not legacy.

• adt_list_versions / adt_compare_versions: when was it last touched, how

actively does it change? (Stable-for-8-years and changed-monthly need very different documentation depth.)

• Optional, NW 7.55+: one or two adt_read_table samples on its Z tables to

show real data shapes (row counts, key examples) — ask before querying business data, and keep samples small.

4. Write the document

Structure (trim sections that don't apply):

# <OBJECT> — <one-line purpose>

## What it does            (3–6 sentences, business language)
## How it's triggered      (jobs, transactions, callers — from where-used)
## Inputs / outputs        (selection screen, interfaces, files, spool)
## Data                    (tables READ / tables WRITTEN — writes first, bold)
## Control flow            (numbered happy path; branches that matter)
## External dependencies   (RFCs, BAPIs, files, config tables)
## Risks & smells          (each with file:line references)
## Change history signal   (last N versions: who, when, what theme)
## Migration notes         (S/4 readiness: deprecated statements, obsolete FMs —
                            apply the abap-clean-core skill's levels if loaded)

Cite everything as INCLUDE/METHOD:line so the next developer can jump straight in. If the user wants the doc persisted, write it to a local markdown file named after the object.

5. Batch mode

For "document the whole package": adt_browse_package to enumerate, then triage — document deeply only objects with DB writes or many callers; one-line summaries for trivial ones. State the triage rule in the output so nobody mistakes a one-liner for a full review.