diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index 4b1b5ab..6799076 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -338,6 +338,10 @@ jobs:
           # requires_plugins = ["Kits", "ZoneManager"] is already a JSON array.
           # One line, quoted strings only; anything else fails the check below.
           REQUIRES="$(grep -m1 -E '^requires_plugins[[:space:]]*=' overlay.toml | sed -E 's/^[^=]*=[[:space:]]*//')"
+          # The RunicNPC API the bridge's npc.* commands need (runicnpc stage 4). 0 when
+          # absent, which a bundle reads as "carries no RunicNPC".
+          RUNICNPC_API="$(grep -m1 -E '^runicnpc_api[[:space:]]*=' overlay.toml | sed -E 's/[^0-9]//g')"
+          RUNICNPC_API="${RUNICNPC_API:-0}"
           [ -n "$PROTOCOL" ]   || { echo "::error::could not read protocol from overlay.toml"; exit 1; }
           [ -n "$MIN_OXIDE" ]  || { echo "::error::could not read min_oxide_version from overlay.toml"; exit 1; }
           [ -n "$MIN_CARBON" ] || { echo "::error::could not read min_carbon_version from overlay.toml"; exit 1; }
@@ -354,6 +358,7 @@ jobs:
             --arg     min_oxide  "${MIN_OXIDE}" \
             --arg     min_carbon "${MIN_CARBON}" \
             --argjson requires   "${REQUIRES}" \
+            --argjson runicnpc   "${RUNICNPC_API}" \
             --argjson files      "${FILES}" \
             '{
                component:          $component,
@@ -364,6 +369,7 @@ jobs:
                min_oxide_version:  $min_oxide,
                min_carbon_version: $min_carbon,
                requires_plugins:   $requires,
+               runicnpc_api:       $runicnpc,
                files:              $files
              }' > "${STAGE}/manifest.json"
           echo "----- manifest.json -----"
diff --git a/overlay.toml b/overlay.toml
index 3093524..5f22132 100644
--- a/overlay.toml
+++ b/overlay.toml
@@ -77,3 +77,15 @@ min_carbon_version = "2.0.259"
 # asked of a server without it is refused with a reason, and chat is the default.
 # BetterChat is optional in the same way — titles and group styles wait for it.
 requires_plugins = ["Kits", "ZoneManager"]
+
+# ── The RunicNPC API the bridge needs ───────────────────────────────────────
+#
+# RunicNPC (docs/runicnpc/PLAN.md stage 4): the bridge's npc.* commands call
+# RunicNPC's API and need at least this version of it. It MUST equal
+# `RunicNpcApiNeeded` in RunicGateway.cs; `node scripts/checkPlugin.js` holds the
+# two equal. The release copies it into manifest.json, and the installer's
+# bundle carries the latest RunicNPC release that answers at least it (D224).
+#
+# RunicNPC is optional to the bridge until its stage 9: without it every npc.*
+# command answers `runicnpc-missing`, and events place Rust's own scientists.
+runicnpc_api = 3
diff --git a/scripts/checkPlugin.js b/scripts/checkPlugin.js
index d7ac002..bf4e078 100644
--- a/scripts/checkPlugin.js
+++ b/scripts/checkPlugin.js
@@ -198,6 +198,14 @@ function check(source, toml) {
 
   // 5. The two declaration sites this repository owns must agree.
   const inCode = /ProtocolVersion\s*=\s*(\d+)\s*;/.exec(source)
+  // runicnpc stage 4: the RunicNPC API the bridge needs, declared twice like the protocol.
+  const npcToml = /^\s*runicnpc_api\s*=\s*(\d+)\s*$/m.exec(toml)
+  const npcCode = /const\s+int\s+RunicNpcApiNeeded\s*=\s*(\d+)\s*;/.exec(source)
+  if (npcCode && !npcToml) problems.push('the plugin needs a RunicNPC API (RunicNpcApiNeeded) and overlay.toml declares no runicnpc_api')
+  if (npcCode && npcToml && npcCode[1] !== npcToml[1]) {
+    problems.push(`the plugin needs RunicNPC API ${npcCode[1]} and overlay.toml declares runicnpc_api = ${npcToml[1]}. The bundle picks a RunicNPC by the second, so they must agree.`)
+  }
+
   const inToml = /^\s*protocol\s*=\s*(\d+)\s*$/m.exec(toml)
 
   if (!inCode) problems.push('could not read ProtocolVersion from the plugin source')