diff --git a/README.md b/README.md
index d040f8c..298f42e 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,8 @@ hdi run                Just run/start commands (aliases: start, r)
 hdi test               Just test commands (alias: t)
 hdi deploy             Just deploy/release commands and platform detection (alias: d)
 hdi all                All sections (aliases: a)
-hdi check              Check if required tools are installed (alias: c)
+hdi contrib            Commands from contributor/development docs (alias: c)
+hdi needs              Check if required tools are installed (alias: n)
 hdi /path/to/project   Scan a different directory
 hdi /path/to/file.md   Parse a specific markdown file
 ```
@@ -78,7 +79,8 @@ hdi r      Run/start commands
 hdi t      Test commands
 hdi d      Deploy/release commands
 hdi a      All sections
-hdi c      Check required tools
+hdi c      Contributor/development docs
+hdi n      Check required tools
 ```
 
 ### Flags
diff --git a/build b/build
index 8eeaff1..b4d4a71 100755
--- a/build
+++ b/build
@@ -16,8 +16,8 @@ sources=(
   src/display.sh
   src/render.sh
   src/picker.sh
-  src/check.sh
   src/platform.sh
+  src/needs.sh
   src/json.sh
   src/main.sh
 )
diff --git a/hdi b/hdi
index 7e321d0..83e70dc 100755
--- a/hdi
+++ b/hdi
@@ -8,7 +8,8 @@
 #   hdi test                      Just test commands (alias: t)
 #   hdi deploy                    Just deploy/release commands and platform detection (alias: d)
 #   hdi all                       Show all matched sections (currently the default mode)
-#   hdi check                     Check if required tools are installed (experimental)
+#   hdi contrib                   Show commands from contributor/development docs (alias: c)
+#   hdi needs                     Check if required tools are installed (alias: n)
 #   hdi [mode] --no-interactive   Print commands without the picker (alias: --ni)
 #   hdi [mode] --full             Include prose around commands
 #   hdi [mode] --raw              Plain markdown output (no colour, good for piping)
@@ -52,7 +53,8 @@ for arg in "$@"; do
     test|t)                 MODE="test" ;;
     deploy|d)               MODE="deploy" ;;
     all|a)                  MODE="all" ;;
-    check|c)                MODE="check" ;;
+    needs|n)                MODE="needs" ;;
+    contrib|c)              MODE="contrib" ;;
     --full|-f)              FULL=true ;;
     --raw)                  RAW=true; INTERACTIVE="no" ;;
     --json)                 JSON=true; INTERACTIVE="no" ;;
@@ -98,7 +100,8 @@ case "$MODE" in
   test)     PATTERN="($KW_TEST)" ;;
   deploy)   PATTERN="($KW_DEPLOY)" ;;
   all)      PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
-  check)    PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
+  needs)    PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
+  contrib)  PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
   default)  PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
 esac
 
@@ -125,16 +128,42 @@ else
   done
 fi
 
-if [[ -z "$README" ]]; then
+if [[ -z "$README" ]] && [[ "$MODE" != "contrib" ]]; then
   echo "${YELLOW}hdi: no README found in ${DIR}${RESET}" >&2
   echo "${DIM}Looked for README.md, readme.md, Readme.md, README.rst${RESET}" >&2
   echo "${DIM}Try: hdi --help${RESET}" >&2
   exit 1
 fi
 
+# ── Discover contributor/development docs ───────────────────────────────────
+CONTRIB_FILES=()
+if [[ -z "$FILE" ]]; then
+  for _cname in CONTRIBUTING.md contributing.md Contributing.md \
+                DEVELOPMENT.md development.md Development.md \
+                DEVELOPERS.md developers.md Developers.md \
+                HACKING.md hacking.md; do
+    [[ -f "$DIR/$_cname" ]] || continue
+    # Deduplicate (case-insensitive filesystems may match multiple variants)
+    _cf_dup=false
+    _cf_real=$(cd "$DIR" && realpath "$_cname" 2>/dev/null || echo "$DIR/$_cname")
+    for _cf_existing in "${CONTRIB_FILES[@]+"${CONTRIB_FILES[@]}"}"; do
+      [[ "$_cf_existing" == "$_cf_real" ]] && _cf_dup=true && break
+    done
+    $_cf_dup || CONTRIB_FILES+=("$_cf_real")
+  done
+fi
+
+if [[ "$MODE" == "contrib" ]] && (( ${#CONTRIB_FILES[@]} == 0 )); then
+  echo "${YELLOW}hdi: no contributor docs found in ${DIR}${RESET}" >&2
+  echo "${DIM}Looked for CONTRIBUTING.md, DEVELOPMENT.md, DEVELOPERS.md, HACKING.md${RESET}" >&2
+  exit 1
+fi
+
 # ── Extract matching sections ────────────────────────────────────────────────
 declare -a SECTION_TITLES=()
 declare -a SECTION_BODIES=()
+declare -a SECTION_FILES=()
+_PARSE_SOURCE=""
 
 parse_sections() {
   local in_section=false
@@ -172,12 +201,14 @@ parse_sections() {
       if (( level <= section_level )); then
         SECTION_TITLES+=("$heading_text")
         SECTION_BODIES+=("$body")
+        SECTION_FILES+=("$_PARSE_SOURCE")
         in_section=false
         body=""
       elif [[ "$text" =~ $PATTERN ]]; then
         # Deeper child heading also matches - save parent body first
         SECTION_TITLES+=("$heading_text")
         SECTION_BODIES+=("$body")
+        SECTION_FILES+=("$_PARSE_SOURCE")
         in_section=false
         body=""
       fi
@@ -297,6 +328,7 @@ parse_sections() {
   if $in_section; then
     SECTION_TITLES+=("$heading_text")
     SECTION_BODIES+=("$body")
+    SECTION_FILES+=("$_PARSE_SOURCE")
   fi
 
   shopt -u nocasematch
@@ -532,9 +564,19 @@ declare -a CMD_INDICES=()     # indices into DISPLAY_LINES that are commands
 declare -a SECTION_FIRST_CMD=()  # cursor indices (into CMD_INDICES) of first cmd per section
 
 build_display_list() {
+  local _prev_source=""
   for i in "${!SECTION_TITLES[@]}"; do
     local title="${SECTION_TITLES[$i]}"
     local body="${SECTION_BODIES[$i]}"
+    local _source="${SECTION_FILES[$i]:-}"
+
+    # File separator when source file changes
+    if [[ -n "$_prev_source" && -n "$_source" && "$_source" != "$_prev_source" ]]; then
+      DISPLAY_LINES+=("$(basename "$_source")")
+      LINE_TYPES+=("filesep")
+      LINE_CMDS+=("")
+    fi
+    _prev_source="$_source"
 
     # Section header
     DISPLAY_LINES+=("$title")
@@ -643,6 +685,13 @@ render_static() {
     local type="${LINE_TYPES[$idx]}"
 
     case "$type" in
+      filesep)
+        if $RAW; then
+          printf "\n--- %s ---\n" "$line"
+        else
+          printf "\n%s  ── %s ──────────────────────────────%s\n" "$DIM" "$line" "$RESET"
+        fi
+        ;;
       header)
         if $RAW; then
           printf "\n## %s\n" "$line"
@@ -677,9 +726,21 @@ render_static() {
 
 # ── Full-prose render ────────────────────────────────────────────────────────
 render_full() {
+  local _rf_prev_source=""
   for i in "${!SECTION_TITLES[@]}"; do
     local title="${SECTION_TITLES[$i]}"
     local content="${SECTION_BODIES[$i]}"
+    local _rf_source="${SECTION_FILES[$i]:-}"
+
+    # File separator when source changes
+    if [[ -n "$_rf_prev_source" && -n "$_rf_source" && "$_rf_source" != "$_rf_prev_source" ]]; then
+      if $RAW; then
+        printf "\n--- %s ---\n" "$(basename "$_rf_source")"
+      else
+        printf "\n%s  ── %s ──────────────────────────────%s\n" "$DIM" "$(basename "$_rf_source")" "$RESET"
+      fi
+    fi
+    _rf_prev_source="$_rf_source"
 
     # Strip trailing blank lines (pure bash, no tail subprocess)
     while [[ "$content" == *$'\n' ]]; do
@@ -810,7 +871,7 @@ _term_height() {
 # Headers/subheaders take 2 lines (blank + text), others take 1
 _SL=1
 _sl() {
-  case "${LINE_TYPES[$1]}" in header|subheader) _SL=2 ;; *) _SL=1 ;; esac
+  case "${LINE_TYPES[$1]}" in header|subheader|filesep) _SL=2 ;; *) _SL=1 ;; esac
 }
 
 # Adjust VIEWPORT_TOP so that the selected item is visible
@@ -842,7 +903,7 @@ adjust_viewport() {
     # Walk back through consecutive headers/subheaders to show full context
     while (( VIEWPORT_TOP > 0 )); do
       local prev_type="${LINE_TYPES[$((VIEWPORT_TOP - 1))]}"
-      if [[ "$prev_type" == "header" || "$prev_type" == "subheader" ]]; then
+      if [[ "$prev_type" == "header" || "$prev_type" == "subheader" || "$prev_type" == "filesep" ]]; then
         (( VIEWPORT_TOP -= 1 ))
       else
         break
@@ -943,6 +1004,7 @@ draw_picker() {
       fi
       ;;
     all)     hdr+="  ${DIM}[all]${RESET}" ;;
+    contrib) hdr+="  ${DIM}[contrib]${RESET}" ;;
   esac
   _line "$hdr"
   local chrome=3
@@ -982,6 +1044,13 @@ draw_picker() {
     fi
 
     case "$type" in
+      filesep)
+        if (( idx != VIEWPORT_TOP )); then
+          _blank; (( rendered += 1 ))
+        fi
+        _line "  ${DIM}── ${line} ──────────────────────────────${RESET}"
+        (( rendered += 1 ))
+        ;;
       header)
         if (( idx != VIEWPORT_TOP )); then
           _blank; (( rendered += 1 ))
@@ -1247,105 +1316,6 @@ run_interactive() {
   done
 }
 
-# ── Check mode: report which tools are installed ─────────────────────────────
-
-# Shell builtins and coreutils that are always available - not worth checking
-_CHECK_SKIP="^(cd|cp|mv|rm|mkdir|echo|export|source|cat|chmod|chown|ln|touch|ls|printf|trap|pwd|set|unset|eval|exec|exit|return|read|test|true|false|tee|head|tail|wc|sort|grep|xargs|find|tar|gzip|gunzip|sed|awk|tr|cut|diff|date|sleep|kill|whoami|env|which|man|less|more)$"
-
-# Extract the tool name from a command string
-# Strips leading env vars (FOO=bar) and sudo, returns the first word
-# Sets _CT_RESULT or "" if nothing useful
-_check_tool_name() {
-  local cmd="$1"
-
-  # Strip leading env vars
-  while [[ "$cmd" =~ ^[A-Za-z_][A-Za-z0-9_]*=[^[:space:]]* ]]; do
-    cmd="${cmd#"${BASH_REMATCH[0]}"}"
-    cmd="${cmd#"${cmd%%[![:space:]]*}"}"
-  done
-
-  # Strip sudo
-  if [[ "$cmd" =~ ^sudo[[:space:]]+ ]]; then
-    cmd="${cmd#sudo}"
-    cmd="${cmd#"${cmd%%[![:space:]]*}"}"
-  fi
-
-  # First word
-  local tool="${cmd%% *}"
-
-  # Skip paths (./foo, /foo, bin/foo), flags (-h, --help), empty, builtins
-  if [[ -z "$tool" ]] || [[ "$tool" == -* ]] || [[ "$tool" == */* ]] || [[ "$tool" =~ $_CHECK_SKIP ]]; then
-    _CT_RESULT=""
-    return
-  fi
-
-  _CT_RESULT="$tool"
-}
-
-run_check() {
-  local -a tools=()
-  local tool
-
-  # Collect unique tool names from all extracted commands
-  for idx in "${!DISPLAY_LINES[@]}"; do
-    [[ "${LINE_TYPES[$idx]}" != "command" ]] && continue
-    _check_tool_name "${LINE_CMDS[$idx]}"
-    [[ -z "$_CT_RESULT" ]] && continue
-    tool="$_CT_RESULT"
-
-    # Deduplicate
-    local seen=false
-    for t in "${tools[@]+"${tools[@]}"}"; do
-      [[ "$t" == "$tool" ]] && seen=true && break
-    done
-    $seen && continue
-    tools+=("$tool")
-  done
-
-  if (( ${#tools[@]} == 0 )); then
-    echo "${YELLOW}hdi: no tool references found in commands${RESET}" >&2
-    echo "${DIM}Try: hdi all --full${RESET}" >&2
-    exit 1
-  fi
-
-  # Header
-  printf "\n%s%s[hdi] %s%s  %scheck (experimental)%s\n\n" "$BOLD" "$YELLOW" "$PROJECT_NAME" "$RESET" "$DIM" "$RESET"
-
-  local found=0 missing=0
-  for tool in "${tools[@]}"; do
-    if command -v "$tool" >/dev/null 2>&1; then
-      # Try to extract a version number (some tools use -V instead of --version)
-      local ver="" raw=""
-      raw=$("$tool" --version 2>&1 | head -5) || true
-      if [[ "$raw" =~ [0-9]+\.[0-9]+[0-9.]* ]]; then
-        ver="${BASH_REMATCH[0]}"
-      else
-        raw=$("$tool" -V 2>&1 | head -5) || true
-        if [[ "$raw" =~ [0-9]+\.[0-9]+[0-9.]* ]]; then
-          ver="${BASH_REMATCH[0]}"
-        fi
-      fi
-
-      if [[ -n "$ver" ]]; then
-        printf "  %s✓%s %-14s %s(%s)%s\n" "$GREEN" "$RESET" "$tool" "$DIM" "$ver" "$RESET"
-      else
-        printf "  %s✓%s %-14s\n" "$GREEN" "$RESET" "$tool"
-      fi
-      found=$((found + 1))
-    else
-      printf "  %s✗%s %-14s %snot found%s\n" "$YELLOW" "$RESET" "$tool" "$DIM" "$RESET"
-      missing=$((missing + 1))
-    fi
-  done
-
-  printf "\n"
-  if (( missing == 0 )); then
-    printf "  %s✓ All %d tools found%s\n\n" "$DIM" "$found" "$RESET"
-  else
-    printf "  %s%d found, %s%d not found%s\n\n" "$DIM" "$found" "$YELLOW" "$missing" "$RESET"
-  fi
-}
-
 # ── Platform detection ────────────────────────────────────────────────────────
 # Detects deployment platforms from three sources:
 #   1. Config files in the project directory (high confidence)
@@ -1484,6 +1454,105 @@ build_platform_display() {
   _PLATFORM_DISPLAY="$parts"
 }
 
+# ── Needs mode: report which tools are installed ─────────────────────────────
+
+# Shell builtins and coreutils that are always available - not worth checking
+_CHECK_SKIP="^(cd|cp|mv|rm|mkdir|echo|export|source|cat|chmod|chown|ln|touch|ls|printf|trap|pwd|set|unset|eval|exec|exit|return|read|test|true|false|tee|head|tail|wc|sort|grep|xargs|find|tar|gzip|gunzip|sed|awk|tr|cut|diff|date|sleep|kill|whoami|env|which|man|less|more)$"
+
+# Extract the tool name from a command string
+# Strips leading env vars (FOO=bar) and sudo, returns the first word
+# Sets _CT_RESULT or "" if nothing useful
+_check_tool_name() {
+  local cmd="$1"
+
+  # Strip leading env vars
+  while [[ "$cmd" =~ ^[A-Za-z_][A-Za-z0-9_]*=[^[:space:]]* ]]; do
+    cmd="${cmd#"${BASH_REMATCH[0]}"}"
+    cmd="${cmd#"${cmd%%[![:space:]]*}"}"
+  done
+
+  # Strip sudo
+  if [[ "$cmd" =~ ^sudo[[:space:]]+ ]]; then
+    cmd="${cmd#sudo}"
+    cmd="${cmd#"${cmd%%[![:space:]]*}"}"
+  fi
+
+  # First word
+  local tool="${cmd%% *}"
+
+  # Skip paths (./foo, /foo, bin/foo), flags (-h, --help), empty, builtins
+  if [[ -z "$tool" ]] || [[ "$tool" == -* ]] || [[ "$tool" == */* ]] || [[ "$tool" =~ $_CHECK_SKIP ]]; then
+    _CT_RESULT=""
+    return
+  fi
+
+  _CT_RESULT="$tool"
+}
+
+run_needs() {
+  local -a tools=()
+  local tool
+
+  # Collect unique tool names from all extracted commands
+  for idx in "${!DISPLAY_LINES[@]}"; do
+    [[ "${LINE_TYPES[$idx]}" != "command" ]] && continue
+    _check_tool_name "${LINE_CMDS[$idx]}"
+    [[ -z "$_CT_RESULT" ]] && continue
+    tool="$_CT_RESULT"
+
+    # Deduplicate
+    local seen=false
+    for t in "${tools[@]+"${tools[@]}"}"; do
+      [[ "$t" == "$tool" ]] && seen=true && break
+    done
+    $seen && continue
+    tools+=("$tool")
+  done
+
+  if (( ${#tools[@]} == 0 )); then
+    echo "${YELLOW}hdi: no tool references found in commands${RESET}" >&2
+    echo "${DIM}Try: hdi all --full${RESET}" >&2
+    exit 1
+  fi
+
+  # Header
+  printf "\n%s%s[hdi] %s%s  %sneeds%s\n\n" "$BOLD" "$YELLOW" "$PROJECT_NAME" "$RESET" "$DIM" "$RESET"
+
+  local found=0 missing=0
+  for tool in "${tools[@]}"; do
+    if command -v "$tool" >/dev/null 2>&1; then
+      # Try to extract a version number (some tools use -V instead of --version)
+      local ver="" raw=""
+      raw=$("$tool" --version 2>&1 | head -5) || true
+      if [[ "$raw" =~ [0-9]+\.[0-9]+[0-9.]* ]]; then
+        ver="${BASH_REMATCH[0]}"
+      else
+        raw=$("$tool" -V 2>&1 | head -5) || true
+        if [[ "$raw" =~ [0-9]+\.[0-9]+[0-9.]* ]]; then
+          ver="${BASH_REMATCH[0]}"
+        fi
+      fi
+
+      if [[ -n "$ver" ]]; then
+        printf "  %s✓%s %-14s %s(%s)%s\n" "$GREEN" "$RESET" "$tool" "$DIM" "$ver" "$RESET"
+      else
+        printf "  %s✓%s %-14s\n" "$GREEN" "$RESET" "$tool"
+      fi
+      found=$((found + 1))
+    else
+      printf "  %s✗%s %-14s %snot found%s\n" "$YELLOW" "$RESET" "$tool" "$DIM" "$RESET"
+      missing=$((missing + 1))
+    fi
+  done
+
+  printf "\n"
+  if (( missing == 0 )); then
+    printf "  %s✓ All %d tools found%s\n\n" "$DIM" "$found" "$RESET"
+  else
+    printf "  %s%d found, %s%d not found%s\n\n" "$DIM" "$found" "$YELLOW" "$missing" "$RESET"
+  fi
+}
+
 # ── JSON output ───────────────────────────────────────────────────────────────
 
 # Escape a string for safe embedding in JSON
@@ -1647,8 +1716,8 @@ _json_full_prose() {
   printf '\n    ]'
 }
 
-# Print the check array as JSON using the current DISPLAY_LINES
-_json_check() {
+# Print the needs array as JSON using the current DISPLAY_LINES
+_json_needs() {
   local -a tools=()
   local tool
 
@@ -1705,7 +1774,7 @@ _json_platforms() {
   fi
 }
 
-# Main JSON renderer: outputs all modes, fullProse, and check
+# Main JSON renderer: outputs all modes, fullProse, and needs
 render_json() {
   local _modes=("default" "install" "run" "test" "deploy" "all")
   local first
@@ -1716,7 +1785,8 @@ render_json() {
     $first || printf ',\n'
     first=false
     _json_set_pattern "$_m"
-    SECTION_TITLES=(); SECTION_BODIES=()
+    SECTION_TITLES=(); SECTION_BODIES=(); SECTION_FILES=()
+    _PARSE_SOURCE="$README"
     parse_sections < "$README"
     DISPLAY_LINES=(); LINE_TYPES=(); LINE_CMDS=(); CMD_INDICES=()
     build_display_list
@@ -1729,19 +1799,21 @@ render_json() {
     $first || printf ',\n'
     first=false
     _json_set_pattern "$_m"
-    SECTION_TITLES=(); SECTION_BODIES=()
+    SECTION_TITLES=(); SECTION_BODIES=(); SECTION_FILES=()
+    _PARSE_SOURCE="$README"
     parse_sections < "$README"
     _json_full_prose "$_m"
   done
 
-  # Re-parse with "all" pattern for check tool extraction
-  printf '\n  },\n  "check": '
+  # Re-parse with "all" pattern for needs tool extraction
+  printf '\n  },\n  "needs": '
   _json_set_pattern "all"
-  SECTION_TITLES=(); SECTION_BODIES=()
+  SECTION_TITLES=(); SECTION_BODIES=(); SECTION_FILES=()
+  _PARSE_SOURCE="$README"
   parse_sections < "$README"
   DISPLAY_LINES=(); LINE_TYPES=(); LINE_CMDS=(); CMD_INDICES=()
   build_display_list
-  _json_check
+  _json_needs
 
   # Platform detection (uses deploy pattern)
   printf ',\n  "platforms": '
@@ -1769,10 +1841,24 @@ if $JSON; then
   exit 0
 fi
 
-parse_sections < "$README"
+# Parse README (unless contrib-only mode)
+if [[ "$MODE" != "contrib" ]] && [[ -n "$README" ]]; then
+  _PARSE_SOURCE="$README"
+  parse_sections < "$README"
+fi
+
+# Parse contributor docs
+for _cf in "${CONTRIB_FILES[@]+"${CONTRIB_FILES[@]}"}"; do
+  _PARSE_SOURCE="$_cf"
+  parse_sections < "$_cf"
+done
 
 if (( ${#SECTION_TITLES[@]} == 0 )); then
-  echo "${YELLOW}hdi: no matching sections found in ${README}${RESET}" >&2
+  if [[ "$MODE" == "contrib" ]]; then
+    echo "${YELLOW}hdi: no matching sections found in contributor docs${RESET}" >&2
+  else
+    echo "${YELLOW}hdi: no matching sections found in ${README}${RESET}" >&2
+  fi
   echo "${DIM}Try: hdi all --full${RESET}" >&2
   exit 1
 fi
@@ -1790,8 +1876,8 @@ if [[ "$MODE" == "deploy" ]]; then
   build_platform_display
 fi
 
-if [[ "$MODE" == "check" ]]; then
-  run_check
+if [[ "$MODE" == "needs" ]]; then
+  run_needs
 elif [[ "$INTERACTIVE" == "yes" ]] && ! $FULL; then
   run_interactive
 else
@@ -1809,6 +1895,7 @@ else
         fi
         ;;
       all)     printf "  %s[all]%s" "$DIM" "$RESET" ;;
+      contrib) printf "  %s[contrib]%s" "$DIM" "$RESET" ;;
     esac
     printf "\n"
   fi
diff --git a/src/args.sh b/src/args.sh
index 50d5a9d..7476416 100644
--- a/src/args.sh
+++ b/src/args.sh
@@ -22,7 +22,8 @@ for arg in "$@"; do
     test|t)                 MODE="test" ;;
     deploy|d)               MODE="deploy" ;;
     all|a)                  MODE="all" ;;
-    check|c)                MODE="check" ;;
+    needs|n)                MODE="needs" ;;
+    contrib|c)              MODE="contrib" ;;
     --full|-f)              FULL=true ;;
     --raw)                  RAW=true; INTERACTIVE="no" ;;
     --json)                 JSON=true; INTERACTIVE="no" ;;
@@ -68,6 +69,7 @@ case "$MODE" in
   test)     PATTERN="($KW_TEST)" ;;
   deploy)   PATTERN="($KW_DEPLOY)" ;;
   all)      PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
-  check)    PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
+  needs)    PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
+  contrib)  PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
   default)  PATTERN="($KW_INSTALL|$KW_RUN|$KW_TEST|$KW_DEPLOY|$KW_EXTRA)" ;;
 esac
diff --git a/src/display.sh b/src/display.sh
index c7e2518..fd1f44d 100644
--- a/src/display.sh
+++ b/src/display.sh
@@ -10,9 +10,19 @@ declare -a CMD_INDICES=()     # indices into DISPLAY_LINES that are commands
 declare -a SECTION_FIRST_CMD=()  # cursor indices (into CMD_INDICES) of first cmd per section
 
 build_display_list() {
+  local _prev_source=""
   for i in "${!SECTION_TITLES[@]}"; do
     local title="${SECTION_TITLES[$i]}"
     local body="${SECTION_BODIES[$i]}"
+    local _source="${SECTION_FILES[$i]:-}"
+
+    # File separator when source file changes
+    if [[ -n "$_prev_source" && -n "$_source" && "$_source" != "$_prev_source" ]]; then
+      DISPLAY_LINES+=("$(basename "$_source")")
+      LINE_TYPES+=("filesep")
+      LINE_CMDS+=("")
+    fi
+    _prev_source="$_source"
 
     # Section header
     DISPLAY_LINES+=("$title")
diff --git a/src/header.sh b/src/header.sh
index cc0b5d7..e44617f 100644
--- a/src/header.sh
+++ b/src/header.sh
@@ -8,7 +8,8 @@
 #   hdi test                      Just test commands (alias: t)
 #   hdi deploy                    Just deploy/release commands and platform detection (alias: d)
 #   hdi all                       Show all matched sections (currently the default mode)
-#   hdi check                     Check if required tools are installed (experimental)
+#   hdi contrib                   Show commands from contributor/development docs (alias: c)
+#   hdi needs                     Check if required tools are installed (alias: n)
 #   hdi [mode] --no-interactive   Print commands without the picker (alias: --ni)
 #   hdi [mode] --full             Include prose around commands
 #   hdi [mode] --raw              Plain markdown output (no colour, good for piping)
diff --git a/src/json.sh b/src/json.sh
index 469a1c3..312102d 100644
--- a/src/json.sh
+++ b/src/json.sh
@@ -161,8 +161,8 @@ _json_full_prose() {
   printf '\n    ]'
 }
 
-# Print the check array as JSON using the current DISPLAY_LINES
-_json_check() {
+# Print the needs array as JSON using the current DISPLAY_LINES
+_json_needs() {
   local -a tools=()
   local tool
 
@@ -219,7 +219,7 @@ _json_platforms() {
   fi
 }
 
-# Main JSON renderer: outputs all modes, fullProse, and check
+# Main JSON renderer: outputs all modes, fullProse, and needs
 render_json() {
   local _modes=("default" "install" "run" "test" "deploy" "all")
   local first
@@ -230,7 +230,8 @@ render_json() {
     $first || printf ',\n'
     first=false
     _json_set_pattern "$_m"
-    SECTION_TITLES=(); SECTION_BODIES=()
+    SECTION_TITLES=(); SECTION_BODIES=(); SECTION_FILES=()
+    _PARSE_SOURCE="$README"
     parse_sections < "$README"
     DISPLAY_LINES=(); LINE_TYPES=(); LINE_CMDS=(); CMD_INDICES=()
     build_display_list
@@ -243,19 +244,21 @@ render_json() {
     $first || printf ',\n'
     first=false
     _json_set_pattern "$_m"
-    SECTION_TITLES=(); SECTION_BODIES=()
+    SECTION_TITLES=(); SECTION_BODIES=(); SECTION_FILES=()
+    _PARSE_SOURCE="$README"
     parse_sections < "$README"
     _json_full_prose "$_m"
   done
 
-  # Re-parse with "all" pattern for check tool extraction
-  printf '\n  },\n  "check": '
+  # Re-parse with "all" pattern for needs tool extraction
+  printf '\n  },\n  "needs": '
   _json_set_pattern "all"
-  SECTION_TITLES=(); SECTION_BODIES=()
+  SECTION_TITLES=(); SECTION_BODIES=(); SECTION_FILES=()
+  _PARSE_SOURCE="$README"
   parse_sections < "$README"
   DISPLAY_LINES=(); LINE_TYPES=(); LINE_CMDS=(); CMD_INDICES=()
   build_display_list
-  _json_check
+  _json_needs
 
   # Platform detection (uses deploy pattern)
   printf ',\n  "platforms": '
diff --git a/src/main.sh b/src/main.sh
index cb3e0b7..c4d65f0 100644
--- a/src/main.sh
+++ b/src/main.sh
@@ -5,10 +5,24 @@ if $JSON; then
   exit 0
 fi
 
-parse_sections < "$README"
+# Parse README (unless contrib-only mode)
+if [[ "$MODE" != "contrib" ]] && [[ -n "$README" ]]; then
+  _PARSE_SOURCE="$README"
+  parse_sections < "$README"
+fi
+
+# Parse contributor docs
+for _cf in "${CONTRIB_FILES[@]+"${CONTRIB_FILES[@]}"}"; do
+  _PARSE_SOURCE="$_cf"
+  parse_sections < "$_cf"
+done
 
 if (( ${#SECTION_TITLES[@]} == 0 )); then
-  echo "${YELLOW}hdi: no matching sections found in ${README}${RESET}" >&2
+  if [[ "$MODE" == "contrib" ]]; then
+    echo "${YELLOW}hdi: no matching sections found in contributor docs${RESET}" >&2
+  else
+    echo "${YELLOW}hdi: no matching sections found in ${README}${RESET}" >&2
+  fi
   echo "${DIM}Try: hdi all --full${RESET}" >&2
   exit 1
 fi
@@ -26,8 +40,8 @@ if [[ "$MODE" == "deploy" ]]; then
   build_platform_display
 fi
 
-if [[ "$MODE" == "check" ]]; then
-  run_check
+if [[ "$MODE" == "needs" ]]; then
+  run_needs
 elif [[ "$INTERACTIVE" == "yes" ]] && ! $FULL; then
   run_interactive
 else
@@ -45,6 +59,7 @@ else
         fi
         ;;
       all)     printf "  %s[all]%s" "$DIM" "$RESET" ;;
+      contrib) printf "  %s[contrib]%s" "$DIM" "$RESET" ;;
     esac
     printf "\n"
   fi
diff --git a/src/check.sh b/src/needs.sh
similarity index 93%
rename from src/check.sh
rename to src/needs.sh
index 48bcf0c..5fc4cc7 100644
--- a/src/check.sh
+++ b/src/needs.sh
@@ -1,4 +1,4 @@
-# ── Check mode: report which tools are installed ─────────────────────────────
+# ── Needs mode: report which tools are installed ─────────────────────────────
 
 # Shell builtins and coreutils that are always available - not worth checking
 _CHECK_SKIP="^(cd|cp|mv|rm|mkdir|echo|export|source|cat|chmod|chown|ln|touch|ls|printf|trap|pwd|set|unset|eval|exec|exit|return|read|test|true|false|tee|head|tail|wc|sort|grep|xargs|find|tar|gzip|gunzip|sed|awk|tr|cut|diff|date|sleep|kill|whoami|env|which|man|less|more)$"
@@ -33,7 +33,7 @@ _check_tool_name() {
   _CT_RESULT="$tool"
 }
 
-run_check() {
+run_needs() {
   local -a tools=()
   local tool
 
@@ -60,7 +60,7 @@ run_check() {
   fi
 
   # Header
-  printf "\n%s%s[hdi] %s%s  %scheck (experimental)%s\n\n" "$BOLD" "$YELLOW" "$PROJECT_NAME" "$RESET" "$DIM" "$RESET"
+  printf "\n%s%s[hdi] %s%s  %sneeds%s\n\n" "$BOLD" "$YELLOW" "$PROJECT_NAME" "$RESET" "$DIM" "$RESET"
 
   local found=0 missing=0
   for tool in "${tools[@]}"; do
diff --git a/src/parse.sh b/src/parse.sh
index f82b764..c442854 100644
--- a/src/parse.sh
+++ b/src/parse.sh
@@ -1,6 +1,8 @@
 # ── Extract matching sections ────────────────────────────────────────────────
 declare -a SECTION_TITLES=()
 declare -a SECTION_BODIES=()
+declare -a SECTION_FILES=()
+_PARSE_SOURCE=""
 
 parse_sections() {
   local in_section=false
@@ -38,12 +40,14 @@ parse_sections() {
       if (( level <= section_level )); then
         SECTION_TITLES+=("$heading_text")
         SECTION_BODIES+=("$body")
+        SECTION_FILES+=("$_PARSE_SOURCE")
         in_section=false
         body=""
       elif [[ "$text" =~ $PATTERN ]]; then
         # Deeper child heading also matches - save parent body first
         SECTION_TITLES+=("$heading_text")
         SECTION_BODIES+=("$body")
+        SECTION_FILES+=("$_PARSE_SOURCE")
         in_section=false
         body=""
       fi
@@ -163,6 +167,7 @@ parse_sections() {
   if $in_section; then
     SECTION_TITLES+=("$heading_text")
     SECTION_BODIES+=("$body")
+    SECTION_FILES+=("$_PARSE_SOURCE")
   fi
 
   shopt -u nocasematch
diff --git a/src/picker.sh b/src/picker.sh
index d638257..171b3d4 100644
--- a/src/picker.sh
+++ b/src/picker.sh
@@ -23,7 +23,7 @@ _term_height() {
 # Headers/subheaders take 2 lines (blank + text), others take 1
 _SL=1
 _sl() {
-  case "${LINE_TYPES[$1]}" in header|subheader) _SL=2 ;; *) _SL=1 ;; esac
+  case "${LINE_TYPES[$1]}" in header|subheader|filesep) _SL=2 ;; *) _SL=1 ;; esac
 }
 
 # Adjust VIEWPORT_TOP so that the selected item is visible
@@ -55,7 +55,7 @@ adjust_viewport() {
     # Walk back through consecutive headers/subheaders to show full context
     while (( VIEWPORT_TOP > 0 )); do
       local prev_type="${LINE_TYPES[$((VIEWPORT_TOP - 1))]}"
-      if [[ "$prev_type" == "header" || "$prev_type" == "subheader" ]]; then
+      if [[ "$prev_type" == "header" || "$prev_type" == "subheader" || "$prev_type" == "filesep" ]]; then
         (( VIEWPORT_TOP -= 1 ))
       else
         break
@@ -156,6 +156,7 @@ draw_picker() {
       fi
       ;;
     all)     hdr+="  ${DIM}[all]${RESET}" ;;
+    contrib) hdr+="  ${DIM}[contrib]${RESET}" ;;
   esac
   _line "$hdr"
   local chrome=3
@@ -195,6 +196,13 @@ draw_picker() {
     fi
 
     case "$type" in
+      filesep)
+        if (( idx != VIEWPORT_TOP )); then
+          _blank; (( rendered += 1 ))
+        fi
+        _line "  ${DIM}── ${line} ──────────────────────────────${RESET}"
+        (( rendered += 1 ))
+        ;;
       header)
         if (( idx != VIEWPORT_TOP )); then
           _blank; (( rendered += 1 ))
diff --git a/src/readme.sh b/src/readme.sh
index 3767bee..3b8aac5 100644
--- a/src/readme.sh
+++ b/src/readme.sh
@@ -9,9 +9,33 @@ else
   done
 fi
 
-if [[ -z "$README" ]]; then
+if [[ -z "$README" ]] && [[ "$MODE" != "contrib" ]]; then
   echo "${YELLOW}hdi: no README found in ${DIR}${RESET}" >&2
   echo "${DIM}Looked for README.md, readme.md, Readme.md, README.rst${RESET}" >&2
   echo "${DIM}Try: hdi --help${RESET}" >&2
   exit 1
 fi
+
+# ── Discover contributor/development docs ───────────────────────────────────
+CONTRIB_FILES=()
+if [[ -z "$FILE" ]]; then
+  for _cname in CONTRIBUTING.md contributing.md Contributing.md \
+                DEVELOPMENT.md development.md Development.md \
+                DEVELOPERS.md developers.md Developers.md \
+                HACKING.md hacking.md; do
+    [[ -f "$DIR/$_cname" ]] || continue
+    # Deduplicate (case-insensitive filesystems may match multiple variants)
+    _cf_dup=false
+    _cf_real=$(cd "$DIR" && realpath "$_cname" 2>/dev/null || echo "$DIR/$_cname")
+    for _cf_existing in "${CONTRIB_FILES[@]+"${CONTRIB_FILES[@]}"}"; do
+      [[ "$_cf_existing" == "$_cf_real" ]] && _cf_dup=true && break
+    done
+    $_cf_dup || CONTRIB_FILES+=("$_cf_real")
+  done
+fi
+
+if [[ "$MODE" == "contrib" ]] && (( ${#CONTRIB_FILES[@]} == 0 )); then
+  echo "${YELLOW}hdi: no contributor docs found in ${DIR}${RESET}" >&2
+  echo "${DIM}Looked for CONTRIBUTING.md, DEVELOPMENT.md, DEVELOPERS.md, HACKING.md${RESET}" >&2
+  exit 1
+fi
diff --git a/src/render.sh b/src/render.sh
index c05bbf6..bfa0aca 100644
--- a/src/render.sh
+++ b/src/render.sh
@@ -5,6 +5,13 @@ render_static() {
     local type="${LINE_TYPES[$idx]}"
 
     case "$type" in
+      filesep)
+        if $RAW; then
+          printf "\n--- %s ---\n" "$line"
+        else
+          printf "\n%s  ── %s ──────────────────────────────%s\n" "$DIM" "$line" "$RESET"
+        fi
+        ;;
       header)
         if $RAW; then
           printf "\n## %s\n" "$line"
@@ -39,9 +46,21 @@ render_static() {
 
 # ── Full-prose render ────────────────────────────────────────────────────────
 render_full() {
+  local _rf_prev_source=""
   for i in "${!SECTION_TITLES[@]}"; do
     local title="${SECTION_TITLES[$i]}"
     local content="${SECTION_BODIES[$i]}"
+    local _rf_source="${SECTION_FILES[$i]:-}"
+
+    # File separator when source changes
+    if [[ -n "$_rf_prev_source" && -n "$_rf_source" && "$_rf_source" != "$_rf_prev_source" ]]; then
+      if $RAW; then
+        printf "\n--- %s ---\n" "$(basename "$_rf_source")"
+      else
+        printf "\n%s  ── %s ──────────────────────────────%s\n" "$DIM" "$(basename "$_rf_source")" "$RESET"
+      fi
+    fi
+    _rf_prev_source="$_rf_source"
 
     # Strip trailing blank lines (pure bash, no tail subprocess)
     while [[ "$content" == *$'\n' ]]; do
diff --git a/test/fixtures/node-express/CONTRIBUTING.md b/test/fixtures/node-express/CONTRIBUTING.md
new file mode 100644
index 0000000..252497a
--- /dev/null
+++ b/test/fixtures/node-express/CONTRIBUTING.md
@@ -0,0 +1,40 @@
+# Contributing to express-api
+
+## Development Setup
+
+Fork the repo and install dependencies:
+
+```bash
+npm install
+cp .env.example .env.test
+```
+
+## Running Tests
+
+Run the full test suite with coverage:
+
+```bash
+npm run test:coverage
+```
+
+Run integration tests only:
+
+```bash
+npm run test:integration
+```
+
+## Code Style
+
+We use ESLint and Prettier. Run the linter before submitting a PR:
+
+```bash
+npm run lint
+npm run format
+```
+
+## Release Process
+
+```bash
+npm version patch
+npm publish
+```
diff --git a/test/hdi.bats b/test/hdi.bats
index f2e1dc7..8dc3b3b 100644
--- a/test/hdi.bats
+++ b/test/hdi.bats
@@ -1359,30 +1359,30 @@ else:
   [[ "$output" == *"npm run serve --env staging"* ]]
 }
 
-# ── Check mode ──────────────────────────────────────────────────────────────
+# ── Needs mode ──────────────────────────────────────────────────────────────
 
-@test "check: reports installed tools" {
-  run "$HDI" check "$FIXTURES/node-express"
+@test "needs: reports installed tools" {
+  run "$HDI" needs "$FIXTURES/node-express"
   [ "$status" -eq 0 ]
   [[ "$output" == *"npm"* ]]
 }
 
-@test "check: marks missing tools" {
-  run "$HDI" check "$FIXTURES/node-express"
+@test "needs: marks missing tools" {
+  run "$HDI" needs "$FIXTURES/node-express"
   [ "$status" -eq 0 ]
   [[ "$output" == *"nvm"* ]]
   [[ "$output" == *"not found"* ]]
 }
 
-@test "check: skips shell builtins like cp" {
-  run "$HDI" check "$FIXTURES/node-express"
+@test "needs: skips shell builtins like cp" {
+  run "$HDI" needs "$FIXTURES/node-express"
   [ "$status" -eq 0 ]
-  # cp is in the install section but should not appear in check output
+  # cp is in the install section but should not appear in needs output
   [[ "$output" != *" cp "* ]]
 }
 
-@test "check: deduplicates tool names" {
-  run "$HDI" check "$FIXTURES/node-express"
+@test "needs: deduplicates tool names" {
+  run "$HDI" needs "$FIXTURES/node-express"
   [ "$status" -eq 0 ]
   # npm appears in multiple commands but should only be listed once
   local count
@@ -1390,22 +1390,22 @@ else:
   [ "$count" -eq 1 ]
 }
 
-@test "check: scans all sections (install + run + test)" {
-  run "$HDI" check "$FIXTURES/react-nextjs"
+@test "needs: scans all sections (install + run + test)" {
+  run "$HDI" needs "$FIXTURES/react-nextjs"
   [ "$status" -eq 0 ]
   [[ "$output" == *"npm"* ]]
 }
 
-@test "check: skips path-like commands" {
-  run "$HDI" check "$FIXTURES/ruby-rails"
+@test "needs: skips path-like commands" {
+  run "$HDI" needs "$FIXTURES/ruby-rails"
   [ "$status" -eq 0 ]
   [[ "$output" != *"bin/rails"* ]]
   [[ "$output" != *"bin/dev"* ]]
 }
 
-@test "check: skips flags in code blocks" {
+@test "needs: skips flags in code blocks" {
   # Flags like -h, --help, --raw should not appear as tools
-  run "$HDI" check "$BATS_TEST_DIRNAME/.."
+  run "$HDI" needs "$BATS_TEST_DIRNAME/.."
   [ "$status" -eq 0 ]
   [[ "$output" != *" -h,"* ]]
   [[ "$output" != *" -v,"* ]]
@@ -1414,6 +1414,62 @@ else:
   [[ "$output" != *" --ni,"* ]]
 }
 
+# ── Contrib mode ───────────────────────────────────────────────────────────
+
+@test "contrib: shows commands from CONTRIBUTING.md" {
+  run "$HDI" contrib "$FIXTURES/node-express"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"npm run test:coverage"* ]]
+  [[ "$output" == *"npm version patch"* ]]
+}
+
+@test "contrib: 'c' is an alias for contrib mode" {
+  run "$HDI" c "$FIXTURES/node-express"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"npm run test:coverage"* ]]
+}
+
+@test "contrib: does not include README commands" {
+  run "$HDI" contrib "$FIXTURES/node-express"
+  [ "$status" -eq 0 ]
+  [[ "$output" != *"npx prisma migrate dev"* ]]
+}
+
+@test "contrib: error when no contributor docs found" {
+  run "$HDI" contrib "$FIXTURES/python-flask"
+  [ "$status" -eq 1 ]
+  [[ "$output" == *"no contributor docs found"* ]]
+}
+
+@test "contrib: default mode includes contrib with separator" {
+  run "$HDI" --ni "$FIXTURES/node-express"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"CONTRIBUTING.md"* ]]
+  [[ "$output" == *"npm run test:coverage"* ]]
+  [[ "$output" == *"npm install"* ]]
+}
+
+@test "contrib: --raw separator uses plain text" {
+  run "$HDI" --raw "$FIXTURES/node-express"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"--- CONTRIBUTING.md ---"* ]]
+}
+
+@test "contrib: mode filter applies to contrib sections" {
+  run "$HDI" test "$FIXTURES/node-express"
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"npm test"* ]]
+  [[ "$output" == *"npm run test:coverage"* ]]
+  # lint/format are not test commands
+  [[ "$output" != *"npm run lint"* ]]
+}
+
+@test "contrib: no separator when no contrib files" {
+  run "$HDI" --ni "$FIXTURES/python-flask"
+  [ "$status" -eq 0 ]
+  [[ "$output" != *"CONTRIBUTING"* ]]
+}
+
 # ── JSON output ────────────────────────────────────────────────────────────
 
 @test "json: produces valid JSON" {
@@ -1438,10 +1494,10 @@ else:
   done
 }
 
-@test "json: contains check array" {
+@test "json: contains needs array" {
   run "$HDI" --json "$FIXTURES/node-express"
   [ "$status" -eq 0 ]
-  echo "$output" | python3 -c "import json,sys; d=json.load(sys.stdin); assert isinstance(d['check'], list)"
+  echo "$output" | python3 -c "import json,sys; d=json.load(sys.stdin); assert isinstance(d['needs'], list)"
 }
 
 @test "json: modes items have type and text fields" {
@@ -1481,13 +1537,13 @@ assert 'header' in types, 'no header items'
 "
 }
 
-@test "json: check items have tool and installed fields" {
+@test "json: needs items have tool and installed fields" {
   run "$HDI" --json "$FIXTURES/node-express"
   [ "$status" -eq 0 ]
   echo "$output" | python3 -c "
 import json,sys
 d=json.load(sys.stdin)
-for item in d['check']:
+for item in d['needs']:
     assert 'tool' in item and 'installed' in item, f'missing fields in {item}'
 "
 }