scan-codebase— agent skill

<objective>

Python only — uses ast.parse to extract import graph + symbol metadata across all .py files; non-Python files not indexed. Writes .cache/codemap/<project>.json. No external deps. Zero-Python project (no .py files): index writes but empty — downstream queries return no results.

Index captures per module: import graph, blast-radius metrics, symbol list (classes, functions, methods with line ranges). Symbol data enables scan-query symbol / find-symbol to return target function source instead of full file reads.

Agents + develop skills query index via scan-query for module deps, blast radius, coupling, symbol source before editing.

NOT for querying existing index (use /codemap:query-code); NOT for integration health checks or injection (use /codemap:integration); NOT for first-time codemap onboarding or injection into skill files (use /codemap:integration init).

</objective>

<workflow>

Step 1: Run the scanner

Parse $ARGUMENTS to build invocation. Pass --root <path> if provided; pass --incremental if provided. Construct args conditionally — never pass literal placeholder strings:

Unsupported flag check — scan $ARGUMENTS for -- prefixed tokens other than --root and --incremental. If any remain: print ! Unknown flag(s): \--<token>\. Supported: \--root\, \--incremental\. then exit 1 — do not invoke AskUserQuestion (disable-model-invocation:true makes AskUserQuestion structurally unreachable). Run this check BEFORE invoking parse_scan_args.py.

# timeout: 10000
_ARGS_UNSUPPORTED=0; _SKIP_NEXT=0
# Unquoted $ARGUMENTS word-splits — --root paths with spaces break; parse_scan_args.py (next) handles quoted paths.
for _FLAG in $ARGUMENTS; do
  [ "$_SKIP_NEXT" -eq 1 ] && { _SKIP_NEXT=0; continue; }
  case "$_FLAG" in
    --root)        _SKIP_NEXT=1 ;;
    --incremental) ;;
    --*) printf "! Unsupported flag: %s\nSupported: --root <path>, --incremental\n" "$_FLAG" >&2; _ARGS_UNSUPPORTED=1 ;;
  esac
done
[ "$_ARGS_UNSUPPORTED" -eq 0 ] || exit 1
SETUP_STDERR="${TMPDIR:-/tmp}/codemap-setup-err-$$"
SCAN_STATE_FILE=$(bash "${CLAUDE_PLUGIN_ROOT:-plugins/codemap}/bin/setup_scan_env.sh" --arguments "$ARGUMENTS" 2>"$SETUP_STDERR")
if [ $? -ne 0 ] || [ -z "$SCAN_STATE_FILE" ]; then
  printf "! setup_scan_env.sh failed"; [ -s "$SETUP_STDERR" ] && printf ": %s" "$(cat "$SETUP_STDERR")"; printf "\n"; exit 1
fi
printf '%s' "$SCAN_STATE_FILE" > "${TMPDIR:-/tmp}/codemap-state-ref"  # persist; subsequent blocks source without knowing PID

# timeout: 360000
SCAN_STATE_FILE=$(cat "${TMPDIR:-/tmp}/codemap-state-ref" 2>/dev/null)
[ -n "$SCAN_STATE_FILE" ] && [ -f "$SCAN_STATE_FILE" ] || { printf "! codemap state missing — re-run from the beginning\n"; exit 1; }
# shellcheck source=/dev/null
. "$SCAN_STATE_FILE"
# Invoke scan-index without eval — args file written NUL-delimited by parse_scan_args.py.
_ARGS_FILE="${TMPDIR:-/tmp}/codemap-scan-args-nul-$$"
python3 "${CLAUDE_PLUGIN_ROOT:-plugins/codemap}/bin/parse_scan_args.py" "$SCAN_ARGS_RAW" --nul-output "$_ARGS_FILE"
SCAN_ARGS=()
while IFS= read -r -d '' _arg; do
  SCAN_ARGS+=("$_arg")
done < "$_ARGS_FILE"
rm -f "$_ARGS_FILE"
if ! "$SCAN_BIN" --timeout 360 "${SCAN_ARGS[@]}"; then
    printf "! scan-index failed (exit %d) — index may be stale or incomplete\n" "$?"
    # Remove incremental-noop sentinel on failure — do not let a failed scan mislead Step 2
    rm -f "${TMPDIR:-/tmp}/codemap-incremental-noop-${PROJ_SLUG}"
    exit 1
fi

`--root` naming note: when --root <path> is provided, the index is named after basename(<path>) — a different name than the default project index (which uses the git root's basename). If you previously queried or modified the default index, the --root index is separate and queries will not see it unless the same --root is used consistently. Run resolve_index_env.py to verify which index path will be used after a custom-root scan.

Scanner writes to <root>/.cache/codemap/<project>.json (or $CODEMAP_INDEX_DIR/<project>.json when set) and prints summary line:

[codemap] ✓ .cache/codemap/<project>.json
[codemap]   N modules indexed, M degraded

Step 2: Report

After scan, read index and report compact summary:

# timeout: 15000
# Only report if index exists — Step 1 may have failed
SCAN_STATE_FILE=$(cat "${TMPDIR:-/tmp}/codemap-state-ref" 2>/dev/null)
[ -n "$SCAN_STATE_FILE" ] && [ -f "$SCAN_STATE_FILE" ] || { printf "! codemap state missing — re-run /codemap:scan-codebase\n"; exit 1; }
# shellcheck source=/dev/null
. "$SCAN_STATE_FILE"
PROJ_NAME="${PROJ_NAME:-$(basename "$(git rev-parse --show-toplevel 2>/dev/null || echo "$PWD")")}"
_IDX="${CODEMAP_INDEX_DIR:-.cache/codemap}"
if [ -f "${_IDX}/${PROJ_NAME}.json" ]; then
    # scan-stats.py reads SCAN_ARGS env var (string form of raw args, e.g. "--root src/mypackage")
    # to resolve the project root and locate the index. Format: space-separated flag tokens.
    SCAN_ARGS="$SCAN_ARGS_RAW" python3 "${CLAUDE_PLUGIN_ROOT:-plugins/codemap}/bin/scan-stats.py"
    # Check if --incremental was requested but fell back to full scan (sentinel set in Step 1)
    if [ -f "${TMPDIR:-/tmp}/codemap-incremental-noop-${PROJ_SLUG}" ]; then
        echo "[codemap] Note: --incremental had no prior index — full scan ran instead"
        rm -f "${TMPDIR:-/tmp}/codemap-incremental-noop-${PROJ_SLUG}"
    fi
else
    echo "[codemap] Skipping stats — no index found (Step 1 may have failed)"
fi

Degraded count reported — scan-stats.py reports module counts only, no per-file list. Not failure — index still useful.

If --incremental passed and no prior index existed, Step 1 sets a sentinel file (codemap-incremental-noop-${PROJ_SLUG}) before the scan starts. Step 2 detects and removes it after stats, logging: --incremental had no prior index — full scan ran instead. If scan fails, Step 1 removes the sentinel to avoid misleading state on the next run.

Sentinel hostname limitation: PROJ_SLUG includes the machine hostname short-name. On Docker containers or cloud instances with dynamic/random hostnames, the sentinel key changes between runs — incremental-noop detection will not fire even when a stale sentinel exists. This is a known limitation; it affects only the informational message in Step 2, not correctness of the scan itself.

Zero-Python project: Step 3 suggestions will return no results — the index is valid but empty.

Step 3: Suggest next step

Index ready. Query it with:
  /codemap:query-code central --top 10
  /codemap:query-code deps <module>
  /codemap:query-code rdeps <module>
  /codemap:query-code coupled --top 10
  # see /codemap:query-code for full list of subcommands

</workflow>