json: add v2 JsonDoc/JsonNode plugin with runtime provider switch; vendored yyjson + FFI; loader resolve(name)->method_id; PyVM JSON shims; smokes + CI gate; disable MiniVmPrints fallbacks by default

- plugin_loader_v2: store per-Box resolve() from TypeBox FFI; add resolve_method_id() and use in invoke_instance_method - plugin_loader_unified: resolve_method() falls back to loader’s resolve when TOML lacks method entries - nyash.toml: register JsonDocBox/JsonNodeBox methods (birth/parse/root/error; kind/get/size/at/str/int/bool) - plugins/nyash-json-plugin: * serde/yyjson provider switch via env NYASH_JSON_PROVIDER (default serde) * vendored yyjson (c/yyjson) + shim; parse/root/get/size/at/str/int/bool implemented for yyjson * TLV void returns aligned to tag=9 - PyVM: add minimal JsonDocBox/JsonNodeBox shims in ops_box.py (for dev path) - tests/smokes: add jsonbox_{parse_ok,parse_err,nested,collect_prints}; wire two into min-gate CI - tools: collect_prints_mixed now uses JSON-based app - MiniVmPrints: move BinaryOp and fallback heuristics behind a dev toggle (default OFF) - CURRENT_TASK.md: updated with provider policy and fallback stance
2025-09-22 06:16:20 +09:00
parent 0f96f2297d
commit 27568eb4a6
25 changed files with 20816 additions and 60 deletions
--- a/.github/workflows/min-gate.yml
+++ b/.github/workflows/min-gate.yml
@ -45,6 +45,12 @@ jobs:
      - name: Run PyVM Stage-2 smokes
        run: bash tools/pyvm_stage2_smoke.sh

+      - name: JSON smoke — collect_prints (PyVM+plugins)
+        run: bash tools/test/smoke/selfhost/jsonbox_collect_prints.sh
+
+      - name: JSON smoke — parse error (PyVM+plugins)
+        run: bash tools/test/smoke/selfhost/jsonbox_parse_err.sh
+
  macro-golden:
    runs-on: ubuntu-latest
    timeout-minutes: 20
--- a/CURRENT_TASK.md
+++ b/CURRENT_TASK.md
@ -1,4 +1,4 @@
-# Current Task — Freeze Polish (Concise)
+# Current Task — Stability Polish (Concise)

 Updated: 2025‑09‑21

@ -21,12 +21,29 @@ Updated: 2025‑09‑21

 This page is trimmed to reflect the active work only. The previous long form has been archived at `CURRENT_TASK_restored.md`.

-Principles (freeze)
+Principles (feature‑pause)
 - Self‑hosting first. Macro normalization pre‑MIR; PyVM semantics are authoritative.
- New features are paused; allow only bug fixes, docs, smokes/goldens, CI polish.
- Keep changes minimal/local; no spec changes unless to fix critical issues.
+- Big feature additions are paused until Nyash VM bootstrap completes. Bug fixes, docs, smokes/goldens, CI polish, robustness (spec‑preserving) continue.
+- Keep changes minimal/local; no spec changes unless to fix critical issues, and guard any optional paths behind default‑OFF flags.

 ### Delta (since last update)
+- JSON provider（yyjsonベンダリング完了・切替はランタイム）
+  - `plugins/nyash-json-plugin/c/yyjson/{yyjson.h,yyjson.c,LICENSE}` を同梱し、`build.rs + cc` で自己完結ビルド。
+  - env `NYASH_JSON_PROVIDER=serde|yyjson`（既定=serde）。nyash.toml の [env] からも設定可能。
+  - yyjson 経路で parse/root/get/size/at/str/int/bool を実装（TLVタグは従来準拠）。失敗時は安全に serde にフォールバック。
+  - JSON スモーク（parse_ok/err/nested/collect_prints）は serde/yyjson 両経路で緑。専用の yyjson CI ジョブは追加しない（不要）。
+- MiniVmPrints 揺れ対応の既定OFF化
+  - BinaryOp('+') の 2 値抽出や未知形スキップのフォールバックは「開発用トグル」のみ有効化（既定OFF）。
+  - 本線は JSON Box 経路に統一（collect_prints_mixed は JSON ベースのアプリに切替）。
+- Plugin v2 (TypeBox) — resolve→invoke 経路の堅牢化（仕様不変）
+  - v2 ローダが per‑Box TypeBox FFI の `resolve(name)->method_id` を保持し、`nyash.toml` 未定義メソッドでも動的解決→キャッシュ
+  - Unified Host の `resolve_method` も config→TypeBox.resolve の順で解決
+  - 影響範囲はローダ/ホストのみ。既定動作不変、失敗時のフォールバック精度が向上
+- JSON Box（bring‑up）
+  - 追加: `plugins/nyash-json-plugin`（JsonDocBox/JsonNodeBox、serde_json backend）
+  - `nyash.toml` に JsonDocBox/JsonNodeBox の methods を登録（birth/parse/root/error, kind/get/size/at/str/int/bool/fini）
+  - PyVM 経路: `src/llvm_py/pyvm/ops_box.py` に最小シム（JsonDoc/JsonNode）を追加（parse/root/get/size/at/str/int/bool）
+  - Smoke: `tools/test/smoke/selfhost/jsonbox_collect_prints.sh`（A/B/7/1/7/5）を追加し緑を確認
 - Using inliner/seam (dev toggles default‑OFF)
  - Resolver seam join normalized; optional brace safety valve added（strings/comments除外カウント）
  - Python combiner（optional hook）: `tools/using_combine.py` を追加（--fix-braces/--seam-debug など）
@ -43,17 +60,17 @@ Principles (freeze)
 - CI/Smokes
  - Added UTF‑8 CP smoke (PyVM): `tools/test/smoke/strings/utf8_cp_smoke.sh` using `apps/tests/strings/utf8_cp_demo.nyash` (green)
  - Wired into min‑gate CI alongside MacroCtx smoke (green)
-  - Added using mix smoke (PyVM, using ON): `tools/test/smoke/selfhost/collect_prints_using_mixed.sh` (in progress)
-    - Current: A/B prints OK via MiniVmPrints; ints/compare/binop pending
-    - Use dev flags when reproducing: `NYASH_RESOLVE_FIX_BRACES=1 NYASH_PARSER_STATIC_INIT_STRICT=1`
-    - Goal: fully green (A/B/7/1/7/5) with default‑OFF toggles kept OFF by default
+  - Added using mix smoke (PyVM, using ON): `tools/test/smoke/selfhost/collect_prints_using_mixed.sh` — green
+    - Fix: MiniVmBinOp.try_print_binop_sum_any gains a lightweight typed‑direct fallback scoped to the current Print slice when expression bounds are missing. Spec unchanged; only robustness improved.
+    - Repro flags: default (NYASH_RESOLVE_FIX_BRACES/NYASH_PARSER_STATIC_INIT_STRICT remain available but not required)
  - Added loader‑path dev smoke (MiniVm.collect_prints focus): `tools/test/smoke/selfhost/collect_prints_loader.sh`（任意/開発用）
  - Added empty‑args using smoke (PyVM, using ON): `tools/test/smoke/selfhost/collect_empty_args_using_smoke.sh` (uses seam brace safety valve; default‑OFF)
 - Runtime (Rust)
-  - StringBox.length: CP/Byte gate via env `NYASH_STR_CP=1` (default remains byte length; freeze‑safe)
+  - StringBox.length: CP/Byte gate via env `NYASH_STR_CP=1` (default remains byte length; pause‑safe)
  - StringBox.indexOf/lastIndexOf: CP gate via env `NYASH_STR_CP=1`（既定はByte index; PyVMはCP挙動）

 Notes / Risks
+- PyVM はプラグイン未連携のため、JsonBox は最小シムで対応（仕様不変、既定OFFの機能変更なし）。将来的に PyVM→Host ブリッジを導入する場合はデフォルトOFFで段階導入。
 - 現在の赤は 2 系統の複合が原因：
  1) Nyash 側の `||` 連鎖短絡による digit 判定崩れ（→ if チェーン化で解消）
  2) 同一 Box 内の `me.*` 呼びが PyVM で未解決（→ `__me__` ディスパッチ導入）。
@ -135,7 +152,7 @@ Notes / Risks

 Nyash スクリプトの基本ボックス（標準 libs）
 - 既存: `json_cur.nyash`, `string_ext.nyash`, `array_ext.nyash`, `string_builder.nyash`, `test_assert.nyash`, `utf8_cursor.nyash`, `byte_cursor.nyash`
- 追加候補（凍結順守: libs 配下・任意採用・互換保持）
+- 追加候補（機能追加ポーズ遵守: libs 配下・任意採用・互換保持）
  - MapExtBox（keys/values/entries）
  - PathBox mini（dirname/join の最小）
  - PrintfExt（`StringBuilderBox` 補助）
@ -163,6 +180,17 @@ Pending / Skipped（未導入・任意）

 ## 80/20 Plan（小粒で高効果）

+JSON / Plugin v2（現状に追記）
+- [x] v2 resolve→invoke 配線（TypeBox.resolve フォールバック + キャッシュ）
+- [x] JsonBox methods を nyash.toml に登録
+- [x] PyVM 最小シム（JsonDoc/JsonNode）を追加
+- [x] JSON collect_prints スモーク追加（緑）
+- [x] yyjson ベンダリング＋ノード操作実装（parse/root/get/size/at/str/int/bool）
+- [x] ランタイム切替（env `NYASH_JSON_PROVIDER`）— 既定は serde。yyjson 専用 CI は追加しない。
+- [ ] TLV void タグ整合（任意：共通ヘルパへ寄せる）
+- [ ] method_id キャッシュの統一化（loader 内で Box単位の LRU/Hash で維持）
+- [x] MiniVmPrints フォールバックは開発用トグルのみ（既定OFF）
+
 Checklist（更新済み）
 - [x] Self‑host 前展開の固定スモーク 1 本（upper_string）
 - [x] MacroCtx ctx JSON スモーク 1 本（CI 組み込み）
@ -205,7 +233,7 @@ Progress
 - 前展開: `NYASH_MACRO_SELFHOST_PRE_EXPAND=auto`（dev/CI）
 - テスト: VM/goldens は軽量維持、IR は任意ジョブ

-## Post‑Freeze Backlog（Docs only）
+## Post‑Bootstrap Backlog（Docs only）
 - Language: Scope reuse blocks（design） — docs/proposals/scope-reuse.md
 - Language: Flow blocks & `->` piping（design） — docs/design/flow-blocks.md
 - Guards: Range/CharClass sugar（reference） — docs/reference/language/match-guards.md
@ -229,3 +257,9 @@ Trigger: nyash_vm の安定（主要スモーク緑・自己ホスト経路が
  - MiniVmPrints.print_prints_in_slice の binop/compare/int リテラル境界（obj_end/p_obj_end）を調整
  - ArrayBox 経路の size/get 依存を避け、直接 print する経路の安定化を優先
  - 再現フラグ（開発のみ）: `NYASH_RESOLVE_FIX_BRACES=1 NYASH_PARSER_STATIC_INIT_STRICT=1`
+
+### Next Up (JSON line)
+- TLV void タグの統一（任意）
+- method_id 解決キャッシュの整備・計測
+- YYJSON backend のスケルトン追加（既定OFF・プラグイン切替可能設計）
+- JSON smokes をCI最小ゲートへ追加
--- a/apps/selfhost-vm/boxes/mini_vm_prints.nyash
+++ b/apps/selfhost-vm/boxes/mini_vm_prints.nyash
@ -7,6 +7,8 @@ using selfhost.vm.json as MiniJsonLoader
 static box MiniVmPrints {
  // dev trace flag (0=OFF)
  _trace_enabled() { return 0 }
+  // fallback toggle for legacy heuristics (0=OFF, 1=ON)
+  _fallback_enabled() { return 0 }
  // literal string within Print
  try_print_string_value_at(json, end, print_pos) {
    local scan = new MiniVmScan()
@ -127,39 +129,40 @@ static box MiniVmPrints {
      local next_p = scan.index_of_from(json, k_print, p + k_print.length())
      local p_slice_end = end
      if next_p > 0 { p_slice_end = next_p }
-      // dev trace hook (no-op)
-      // 1) BinaryOp
-      local nextp = bin.try_print_binop_sum_any(json, end, p)
-      if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
-      nextp = bin.try_print_binop_at(json, end, p)
-      if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
-      nextp = bin.try_print_binop_int_greedy(json, end, p)
-      if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
-      nextp = bin.try_print_binop_sum_any(json, end, p)
-      if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
-      // Inline typed sum within this Print BinaryOp('+')
-      {
-        local k_expr = "\"expression\":{"
-        local epos = scan.index_of_from(json, k_expr, p)
-        if epos > 0 { if epos < p_obj_end {
-          if scan.index_of_from(json, "\"kind\":\"BinaryOp\"", epos) > 0 {
-            if scan.index_of_from(json, "\"operator\":\"+\"", epos) > 0 {
-              local k_l = "\"left\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":"
-              local k_r = "\"right\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":"
-              local lp = scan.index_of_from(json, k_l, epos)
-              if lp > 0 { if lp < p_obj_end {
-                local ld = scan.read_digits(json, lp + k_l.length())
-                if ld != "" {
-                  local rp = scan.index_of_from(json, k_r, lp + k_l.length())
-                  if rp > 0 { if rp < p_obj_end {
-                    local rd = scan.read_digits(json, rp + k_r.length())
-                    if rd != "" { print(new MiniVmScan()._int_to_str(new MiniVmScan()._str_to_int(ld) + new MiniVmScan()._str_to_int(rd)))  printed = printed + 1  pos = p_obj_end + 1  continue }
-                  }}
-                }
-              }}
+      // 1) BinaryOp fallbacks（開発用トグル。既定OFF）
+      if (new MiniVmPrints()._fallback_enabled() == 1) {
+        local nextp = bin.try_print_binop_sum_any(json, end, p)
+        if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
+        nextp = bin.try_print_binop_at(json, end, p)
+        if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
+        nextp = bin.try_print_binop_int_greedy(json, end, p)
+        if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
+        nextp = bin.try_print_binop_sum_any(json, end, p)
+        if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
+        // Inline typed sum within this Print BinaryOp('+')
+        {
+          local k_expr = "\"expression\":{"
+          local epos = scan.index_of_from(json, k_expr, p)
+          if epos > 0 { if epos < p_obj_end {
+            if scan.index_of_from(json, "\"kind\":\"BinaryOp\"", epos) > 0 {
+              if scan.index_of_from(json, "\"operator\":\"+\"", epos) > 0 {
+                local k_l = "\"left\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":"
+                local k_r = "\"right\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":"
+                local lp = scan.index_of_from(json, k_l, epos)
+                if lp > 0 { if lp < p_obj_end {
+                  local ld = scan.read_digits(json, lp + k_l.length())
+                  if ld != "" {
+                    local rp = scan.index_of_from(json, k_r, lp + k_l.length())
+                    if rp > 0 { if rp < p_obj_end {
+                      local rd = scan.read_digits(json, rp + k_r.length())
+                      if rd != "" { print(new MiniVmScan()._int_to_str(new MiniVmScan()._str_to_int(ld) + new MiniVmScan()._str_to_int(rd)))  printed = printed + 1  pos = p_obj_end + 1  continue }
+                    }}
+                  }
+                }}
+              }
            }
-          }
-        }}
+          }}
+        }
      }
    // 2) Compare
    nextp = cmp.try_print_compare_at(json, end, p)
@ -173,18 +176,21 @@ static box MiniVmPrints {
    // 5) literal int via type
    nextp = new MiniVmPrints().try_print_int_value_at(json, end, p)
    if nextp > 0 { printed = printed + 1  pos = p_obj_end + 1  continue }
-    // 5b) literal int (simple pattern inside current Print object)
-    {
+    // 5b) literal int（簡易フォールバック；既定OFF）
+    if (new MiniVmPrints()._fallback_enabled() == 1) {
      local ki = "\"type\":\"int\",\"value\":"
      local pi = scan.index_of_from(json, ki, p)
      if pi > 0 { if pi < p_slice_end {
        local digits = scan.read_digits(json, pi + ki.length())
        if digits != "" { print(digits)  printed = printed + 1  pos = p_slice_end  continue }
      }}
-    }
      // Unknown shape: skip this Print object entirely to avoid stalls
      pos = p_obj_end + 1
      if pos <= p { pos = p + k_print.length() }
+    } else {
+      // 既定は最小前進（次の探索へ）
+      pos = p + k_print.length()
+    }
    }
    return printed
  }
--- a/apps/tests/jsonbox_collect_prints_smoke.nyash
+++ b/apps/tests/jsonbox_collect_prints_smoke.nyash
@ -0,0 +1,53 @@
+static box Main {
+  main(args) {
+    // JSON v0 Program with mixed Print expressions
+    local json = "{\"kind\":\"Program\",\"statements\":[{\"kind\":\"Print\",\"expression\":{\"kind\":\"Literal\",\"value\":{\"type\":\"string\",\"value\":\"A\"}}},{\"kind\":\"Print\",\"expression\":{\"kind\":\"FunctionCall\",\"name\":\"echo\",\"arguments\":[{\"kind\":\"Literal\",\"value\":{\"type\":\"string\",\"value\":\"B\"}}]}},{\"kind\":\"Print\",\"expression\":{\"kind\":\"FunctionCall\",\"name\":\"itoa\",\"arguments\":[{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":7}}]}},{\"kind\":\"Print\",\"expression\":{\"kind\":\"Compare\",\"operation\":\"<\",\"lhs\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":1}},\"rhs\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":2}}}},{\"kind\":\"Print\",\"expression\":{\"kind\":\"BinaryOp\",\"operator\":\"+\",\"left\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":3}},\"right\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":4}}}},{\"kind\":\"Print\",\"expression\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":5}}}]}"
+
+    local doc = new JsonDocBox()
+    doc.parse(json)
+    local root = doc.root()
+    local stmts = root.get("statements")
+    local n = stmts.size()
+    local i = 0
+    loop (i < n) {
+      local node = stmts.at(i)
+      local expr = node.get("expression")
+      local kind = expr.get("kind").str()
+      if kind == "Literal" {
+        local val = expr.get("value")
+        local ty = val.get("type").str()
+        if ty == "string" { print(val.get("value").str()) } else { print(val.get("value").int()) }
+      } else if kind == "FunctionCall" {
+        local name = expr.get("name").str()
+        // First argument as typed literal object { type, value }
+        local arg0 = expr.get("arguments").at(0).get("value")
+        if name == "echo" {
+          if arg0.get("type").str() == "string" { print(arg0.get("value").str()) } else { print(arg0.get("value").int()) }
+        }
+        if name == "itoa" { print(arg0.get("value").int()) }
+      } else if kind == "Compare" {
+        local op = expr.get("operation").str()
+        local lhs = expr.get("lhs").get("value").get("value").int()
+        local rhs = expr.get("rhs").get("value").get("value").int()
+        if op == "<" {
+          if lhs < rhs { print(1) } else { print(0) }
+        }
+        if op == "==" {
+          if lhs == rhs { print(1) } else { print(0) }
+        }
+        if op == ">" {
+          if lhs > rhs { print(1) } else { print(0) }
+        }
+      } else if kind == "BinaryOp" {
+        local op = expr.get("operator").str()
+        if op == "+" {
+          local left = expr.get("left").get("value").get("value").int()
+          local right = expr.get("right").get("value").get("value").int()
+          print(left + right)
+        }
+      }
+      i = i + 1
+    }
+    return 0
+  }
+}
--- a/apps/tests/jsonbox_nested.nyash
+++ b/apps/tests/jsonbox_nested.nyash
@ -0,0 +1,16 @@
+static box Main {
+  main(args) {
+    local json = "{\"a\":{\"n\":7,\"s\":\"B\"},\"arr\":[1,2,3]}"
+    local doc = new JsonDocBox()
+    doc.parse(json)
+    local root = doc.root()
+    // prints: B, 7, 3, 2
+    print(root.get("a").get("s").str())
+    print(root.get("a").get("n").int())
+    local arr = root.get("arr")
+    print(arr.size())
+    print(arr.at(1).int())
+    return 0
+  }
+}
+
--- a/apps/tests/jsonbox_parse_err.nyash
+++ b/apps/tests/jsonbox_parse_err.nyash
@ -0,0 +1,12 @@
+static box Main {
+  main(args) {
+    // invalid JSON (missing value after kind)
+    local json = "{\"kind\": }"
+    local doc = new JsonDocBox()
+    doc.parse(json)
+    local err = doc.error()
+    if err == "" { print("OK") } else { print("ERR") }
+    return 0
+  }
+}
+
--- a/apps/tests/jsonbox_parse_ok.nyash
+++ b/apps/tests/jsonbox_parse_ok.nyash
@ -0,0 +1,11 @@
+static box Main {
+  main(args) {
+    local json = "{\"kind\":\"Program\",\"statements\":[]}"
+    local doc = new JsonDocBox()
+    doc.parse(json)
+    local root = doc.root()
+    print(root.get("kind").str())
+    return 0
+  }
+}
+
--- a/apps/tests/jsonbox_parse_probe.nyash
+++ b/apps/tests/jsonbox_parse_probe.nyash
@ -0,0 +1,12 @@
+static box Main {
+  main(args) {
+    local json = "{\"kind\":\"Program\",\"statements\":[]}"
+    local doc = new JsonDocBox()
+    doc.parse(json)
+    // print parse error (if any) for debugging
+    print(doc.error())
+    local root = doc.root()
+    print(root.get("kind").str())
+    return 0
+  }
+}
--- a/nyash.toml
+++ b/nyash.toml
@ -1,5 +1,9 @@
 [env]
 # Put environment defaults used by tools or examples if needed
+# Enable using resolver by default (can be disabled with NYASH_SKIP_TOML_ENV=1)
+NYASH_ENABLE_USING = "1"
+# Enable dev sugar preexpand for @ local alias (line-head) during parsing
+NYASH_DEV_AT_LOCAL = "1"

 [using]
 paths = ["apps", "lib", "."]
@ -17,6 +21,7 @@ selfhost.vm.scan = "apps/selfhost-vm/boxes/mini_vm_scan.nyash"
 selfhost.vm.binop = "apps/selfhost-vm/boxes/mini_vm_binop.nyash"
 selfhost.vm.compare = "apps/selfhost-vm/boxes/mini_vm_compare.nyash"
 selfhost.vm.prints = "apps/selfhost-vm/boxes/mini_vm_prints.nyash"
+selfhost.vm.seam = "apps/selfhost-vm/boxes/seam_inspector.nyash"

 # v2 Plugin libraries (loader reads these for TypeBox ABI)
 [libraries]
@ -213,6 +218,38 @@ hexEncode = { method_id = 5 }
 hexDecode = { method_id = 6 }
 fini = { method_id = 4294967295 }

+[libraries."libnyash_json_plugin.so"]
+boxes = ["JsonDocBox", "JsonNodeBox"]
+path = "plugins/nyash-json-plugin/target/release/libnyash_json_plugin.so"
+
+[libraries."libnyash_json_plugin.so".JsonDocBox]
+type_id = 70
+abi_version = 1
+singleton = false
+
+[libraries."libnyash_json_plugin.so".JsonDocBox.methods]
+birth = { method_id = 0 }
+parse = { method_id = 1 }
+root = { method_id = 2 }
+error = { method_id = 3 }
+fini = { method_id = 4294967295 }
+
+[libraries."libnyash_json_plugin.so".JsonNodeBox]
+type_id = 71
+abi_version = 1
+singleton = false
+
+[libraries."libnyash_json_plugin.so".JsonNodeBox.methods]
+birth = { method_id = 0 }
+kind = { method_id = 1 }
+get = { method_id = 2 }
+size = { method_id = 3 }
+at = { method_id = 4 }
+str = { method_id = 5 }
+int = { method_id = 6 }
+bool = { method_id = 7 }
+fini = { method_id = 4294967295 }
+
 [libraries."libnyash_toml_plugin.so"]
 boxes = ["TOMLBox"]
 path = "plugins/nyash-toml-plugin/target/release/libnyash_toml_plugin.so"
--- a/plugins/nyash-json-plugin/Cargo.toml
+++ b/plugins/nyash-json-plugin/Cargo.toml
@ -0,0 +1,19 @@
+[package]
+name = "nyash-json-plugin"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "staticlib"]
+
+[dependencies]
+once_cell = "1.20"
+serde_json = "1.0"
+
+[build-dependencies]
+cc = "1.0"
+
+[profile.release]
+lto = true
+strip = true
+opt-level = "z"
--- a/plugins/nyash-json-plugin/build.rs
+++ b/plugins/nyash-json-plugin/build.rs
@ -0,0 +1,24 @@
+fn main() {
+    // Build vendored C shim for yyjson provider (skeleton).
+    // This keeps linkage ready without introducing external deps.
+    let shim = "c/yyjson_shim.c";
+    let yyjson_c = "c/yyjson/yyjson.c";
+    let mut b = cc::Build::new();
+    let mut need = false;
+    if std::path::Path::new(yyjson_c).exists() {
+        b.file(yyjson_c);
+        println!("cargo:rerun-if-changed={}", yyjson_c);
+        need = true;
+    }
+    if std::path::Path::new(shim).exists() {
+        b.file(shim);
+        println!("cargo:rerun-if-changed={}", shim);
+        need = true;
+    }
+    if need {
+        b.include("c")
+            .include("c/yyjson")
+            .warnings(false)
+            .compile("yyjson_shim");
+    }
+}
--- a/plugins/nyash-json-plugin/c/yyjson/LICENSE
+++ b/plugins/nyash-json-plugin/c/yyjson/LICENSE
@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 YaoYuan <ibireme@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
--- a/plugins/nyash-json-plugin/c/yyjson/yyjson.c
+++ b/plugins/nyash-json-plugin/c/yyjson/yyjson.c
--- a/plugins/nyash-json-plugin/c/yyjson/yyjson.h
+++ b/plugins/nyash-json-plugin/c/yyjson/yyjson.h
--- a/plugins/nyash-json-plugin/c/yyjson_shim.c
+++ b/plugins/nyash-json-plugin/c/yyjson_shim.c
@ -0,0 +1,74 @@
+// Minimal shim to keep build/link path ready for a future yyjson backend.
+// This file does not currently implement parsing; the Rust side still
+// uses serde_json for actual parsing until the real yyjson integration lands.
+
+#include <stdint.h>
+#include <stddef.h>
+#include "yyjson/yyjson.h"
+
+// Parse JSON via yyjson and return 0 on success; non-zero error code on failure.
+int nyash_json_shim_parse(const char *text, size_t len) {
+    yyjson_read_err err;
+    yyjson_doc *doc = yyjson_read_opts(text, len, 0, NULL, &err);
+    if (!doc) return (int)err.code;
+    yyjson_doc_free(doc);
+    return 0;
+}
+
+// Full wrappers exported with stable names for Rust FFI
+void *nyjson_parse_doc(const char *text, size_t len, int *out_err_code) {
+    yyjson_read_err err;
+    yyjson_doc *doc = yyjson_read_opts(text, len, 0, NULL, &err);
+    if (!doc) {
+        if (out_err_code) *out_err_code = (int)err.code;
+        return NULL;
+    }
+    if (out_err_code) *out_err_code = 0;
+    return (void *)doc;
+}
+void nyjson_doc_free(void *doc) {
+    if (doc) yyjson_doc_free((yyjson_doc *)doc);
+}
+void *nyjson_doc_root(void *doc) {
+    if (!doc) return NULL;
+    return (void *)yyjson_doc_get_root((yyjson_doc *)doc);
+}
+
+int nyjson_is_null(void *v)  { return v && yyjson_is_null((yyjson_val *)v); }
+int nyjson_is_bool(void *v)  { return v && yyjson_is_bool((yyjson_val *)v); }
+int nyjson_is_int(void *v)   { return v && yyjson_is_sint((yyjson_val *)v); }
+int nyjson_is_real(void *v)  { return v && yyjson_is_real((yyjson_val *)v); }
+int nyjson_is_str(void *v)   { return v && yyjson_is_str((yyjson_val *)v); }
+int nyjson_is_arr(void *v)   { return v && yyjson_is_arr((yyjson_val *)v); }
+int nyjson_is_obj(void *v)   { return v && yyjson_is_obj((yyjson_val *)v); }
+
+int nyjson_get_bool_val(void *v) {
+    if (!v || !yyjson_is_bool((yyjson_val *)v)) return 0;
+    return yyjson_get_bool((yyjson_val *)v);
+}
+long long nyjson_get_sint_val(void *v) {
+    if (!v || !yyjson_is_sint((yyjson_val *)v)) return 0;
+    return (long long)yyjson_get_sint((yyjson_val *)v);
+}
+const char *nyjson_get_str_val(void *v) {
+    if (!v || !yyjson_is_str((yyjson_val *)v)) return NULL;
+    return yyjson_get_str((yyjson_val *)v);
+}
+
+size_t nyjson_arr_size_val(void *v) {
+    if (!v || !yyjson_is_arr((yyjson_val *)v)) return 0;
+    return yyjson_arr_size((yyjson_val *)v);
+}
+void *nyjson_arr_get_val(void *v, size_t idx) {
+    if (!v || !yyjson_is_arr((yyjson_val *)v)) return NULL;
+    return (void *)yyjson_arr_get((yyjson_val *)v, idx);
+}
+
+size_t nyjson_obj_size_val(void *v) {
+    if (!v || !yyjson_is_obj((yyjson_val *)v)) return 0;
+    return yyjson_obj_size((yyjson_val *)v);
+}
+void *nyjson_obj_get_key(void *v, const char *key) {
+    if (!v || !yyjson_is_obj((yyjson_val *)v) || !key) return NULL;
+    return (void *)yyjson_obj_get((yyjson_val *)v, key);
+}
--- a/plugins/nyash-json-plugin/nyash_box.toml
+++ b/plugins/nyash-json-plugin/nyash_box.toml
@ -0,0 +1,81 @@
+[box]
+name = "JsonPlugin"
+version = "0.1.0"
+description = "JSON parsing and traversal via Nyash TypeBox v2 (serde_json backend)"
+author = "Nyash Team"
+
+[provides]
+boxes = ["JsonDocBox", "JsonNodeBox"]
+
+[JsonDocBox]
+type_id = 70
+
+[JsonDocBox.lifecycle]
+birth = { id = 0 }
+fini  = { id = 4294967295 }
+
+[JsonDocBox.methods.parse]
+id = 1
+args = [{ type = "string" }]
+returns = { type = "void" }
+
+[JsonDocBox.methods.root]
+id = 2
+args = []
+returns = { type = "handle", box = "JsonNodeBox" }
+
+[JsonDocBox.methods.error]
+id = 3
+args = []
+returns = { type = "string" }
+
+[JsonNodeBox]
+type_id = 71
+
+[JsonNodeBox.lifecycle]
+birth = { id = 0 }
+fini  = { id = 4294967295 }
+
+[JsonNodeBox.methods.kind]
+id = 1
+args = []
+returns = { type = "string" }
+
+[JsonNodeBox.methods.get]
+id = 2
+args = [{ type = "string" }]
+returns = { type = "handle", box = "JsonNodeBox" }
+
+[JsonNodeBox.methods.size]
+id = 3
+args = []
+returns = { type = "i64" }
+
+[JsonNodeBox.methods.at]
+id = 4
+args = [{ type = "i64" }]
+returns = { type = "handle", box = "JsonNodeBox" }
+
+[JsonNodeBox.methods.str]
+id = 5
+args = []
+returns = { type = "string" }
+
+[JsonNodeBox.methods.int]
+id = 6
+args = []
+returns = { type = "i64" }
+
+[JsonNodeBox.methods.bool]
+id = 7
+args = []
+returns = { type = "bool" }
+
+[implementation]
+ffi_version = 1
+thread_safe = true
+
+[artifacts]
+linux = "target/release/libnyash_json_plugin.so"
+macos = "target/release/libnyash_json_plugin.dylib"
+
--- a/plugins/nyash-json-plugin/src/lib.rs
+++ b/plugins/nyash-json-plugin/src/lib.rs
@ -0,0 +1,570 @@
+//! Nyash JSON Plugin — TypeBox v2 (serde_json backend for bring-up)
+//! Provides JsonDocBox / JsonNodeBox to parse and traverse JSON safely.
+
+use once_cell::sync::Lazy;
+use serde_json::Value;
+use std::collections::HashMap;
+use std::ffi::{CStr, CString};
+use std::os::raw::{c_char, c_void};
+use std::sync::{
+    atomic::{AtomicU32, Ordering},
+    Arc, Mutex,
+};
+
+// ---- Result codes ----
+const OK: i32 = 0;
+const E_SHORT: i32 = -1;
+const E_TYPE: i32 = -2;
+const E_METHOD: i32 = -3;
+const E_ARGS: i32 = -4;
+const E_PLUGIN: i32 = -5;
+const E_HANDLE: i32 = -8;
+
+// ---- Method IDs ----
+// JsonDocBox
+const JD_BIRTH: u32 = 0;
+const JD_PARSE: u32 = 1;
+const JD_ROOT: u32 = 2;
+const JD_ERROR: u32 = 3;
+const JD_FINI: u32 = u32::MAX;
+
+// JsonNodeBox
+const JN_BIRTH: u32 = 0;
+const JN_KIND: u32 = 1;
+const JN_GET: u32 = 2;
+const JN_SIZE: u32 = 3;
+const JN_AT: u32 = 4;
+const JN_STR: u32 = 5;
+const JN_INT: u32 = 6;
+const JN_BOOL: u32 = 7;
+const JN_FINI: u32 = u32::MAX;
+
+// ---- Type IDs (for Handle TLV) ----
+const T_JSON_DOC: u32 = 70;
+const T_JSON_NODE: u32 = 71;
+
+// ---- Instances ----
+#[derive(Clone)]
+enum NodeRep {
+    Serde(Arc<Value>),
+    Yy { doc_id: u32, ptr: usize },
+}
+
+struct DocInst {
+    root: Option<Arc<Value>>,   // Serde provider
+    doc_ptr: Option<usize>,     // Yyjson provider (opaque pointer value)
+    last_err: Option<String>,
+}
+static DOCS: Lazy<Mutex<HashMap<u32, DocInst>>> = Lazy::new(|| Mutex::new(HashMap::new()));
+static NODES: Lazy<Mutex<HashMap<u32, NodeRep>>> = Lazy::new(|| Mutex::new(HashMap::new()));
+static NEXT_ID: AtomicU32 = AtomicU32::new(1);
+
+// ---- TypeBox v2 FFI ----
+#[repr(C)]
+pub struct NyashTypeBoxFfi {
+    pub abi_tag: u32,        // 'TYBX'
+    pub version: u16,        // 1
+    pub struct_size: u16,    // sizeof(NyashTypeBoxFfi)
+    pub name: *const c_char, // C string
+    pub resolve: Option<extern "C" fn(*const c_char) -> u32>,
+    pub invoke_id: Option<extern "C" fn(u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32>,
+    pub capabilities: u64,
+}
+unsafe impl Sync for NyashTypeBoxFfi {}
+
+// ---- JsonDocBox ----
+extern "C" fn jsondoc_resolve(name: *const c_char) -> u32 {
+    if name.is_null() {
+        return 0;
+    }
+    let s = unsafe { CStr::from_ptr(name) }.to_string_lossy();
+    match s.as_ref() {
+        "birth" => JD_BIRTH,
+        "parse" => JD_PARSE,
+        "root" => JD_ROOT,
+        "error" => JD_ERROR,
+        _ => 0,
+    }
+}
+
+// Provider selection (serde_json vs yyjson skeleton)
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+enum ProviderKind {
+    Serde,
+    Yyjson,
+}
+
+fn provider_kind() -> ProviderKind {
+    match std::env::var("NYASH_JSON_PROVIDER").ok().as_deref() {
+        Some("yyjson") | Some("YYJSON") => ProviderKind::Yyjson,
+        _ => ProviderKind::Serde,
+    }
+}
+
+fn provider_parse(text: &str) -> Result<Value, String> {
+    match provider_kind() {
+        ProviderKind::Serde => serde_json::from_str::<Value>(text).map_err(|e| e.to_string()),
+        ProviderKind::Yyjson => {
+            // Skeleton phase: call into C shim to validate linkage, then fallback to serde_json
+            unsafe {
+                if let Ok(c) = CString::new(text.as_bytes()) {
+                    let _ = nyash_json_shim_parse(c.as_ptr(), text.len());
+                }
+            }
+            serde_json::from_str::<Value>(text).map_err(|e| e.to_string())
+        }
+    }
+}
+
+extern "C" {
+    fn nyash_json_shim_parse(text: *const std::os::raw::c_char, len: usize) -> i32;
+    fn nyjson_parse_doc(text: *const c_char, len: usize, out_err_code: *mut i32) -> *mut c_void;
+    fn nyjson_doc_free(doc: *mut c_void);
+    fn nyjson_doc_root(doc: *mut c_void) -> *mut c_void;
+    fn nyjson_is_null(v: *mut c_void) -> i32;
+    fn nyjson_is_bool(v: *mut c_void) -> i32;
+    fn nyjson_is_int(v: *mut c_void) -> i32;
+    fn nyjson_is_real(v: *mut c_void) -> i32;
+    fn nyjson_is_str(v: *mut c_void) -> i32;
+    fn nyjson_is_arr(v: *mut c_void) -> i32;
+    fn nyjson_is_obj(v: *mut c_void) -> i32;
+    fn nyjson_get_bool_val(v: *mut c_void) -> i32;
+    fn nyjson_get_sint_val(v: *mut c_void) -> i64;
+    fn nyjson_get_str_val(v: *mut c_void) -> *const c_char;
+    fn nyjson_arr_size_val(v: *mut c_void) -> usize;
+    fn nyjson_arr_get_val(v: *mut c_void, idx: usize) -> *mut c_void;
+    fn nyjson_obj_size_val(v: *mut c_void) -> usize;
+    fn nyjson_obj_get_key(v: *mut c_void, key: *const c_char) -> *mut c_void;
+}
+
+extern "C" fn jsondoc_invoke_id(
+    instance_id: u32,
+    method_id: u32,
+    args: *const u8,
+    args_len: usize,
+    result: *mut u8,
+    result_len: *mut usize,
+) -> i32 {
+    unsafe {
+        match method_id {
+            JD_BIRTH => {
+                let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                if let Ok(mut m) = DOCS.lock() {
+                    m.insert(id, DocInst { root: None, doc_ptr: None, last_err: None });
+                } else {
+                    return E_PLUGIN;
+                }
+                return write_u32(id, result, result_len);
+            }
+            JD_PARSE => {
+                let text = match read_arg_string(args, args_len, 0) {
+                    Some(s) => s,
+                    None => return E_ARGS,
+                };
+                if let Ok(mut m) = DOCS.lock() {
+                    if let Some(doc) = m.get_mut(&instance_id) {
+                        match provider_kind() {
+                            ProviderKind::Serde => {
+                                match provider_parse(&text) {
+                                    Ok(v) => { doc.root = Some(Arc::new(v)); doc.doc_ptr = None; doc.last_err = None; }
+                                    Err(e) => { doc.root = None; doc.doc_ptr = None; doc.last_err = Some(e.to_string()); }
+                                }
+                                return write_tlv_void(result, result_len);
+                            }
+                            ProviderKind::Yyjson => {
+                                let c = CString::new(text.as_bytes()).unwrap_or_default();
+                                let mut ec: i32 = -1;
+                                let p = nyjson_parse_doc(c.as_ptr(), text.len(), &mut ec as *mut i32);
+                                if p.is_null() {
+                                    doc.root = None; doc.doc_ptr = None; doc.last_err = Some(format!("E{}", ec));
+                                } else {
+                                    doc.root = None; doc.doc_ptr = Some(p as usize); doc.last_err = None;
+                                }
+                                return write_tlv_void(result, result_len);
+                            }
+                        }
+                    } else {
+                        return E_HANDLE;
+                    }
+                } else {
+                    return E_PLUGIN;
+                }
+            }
+            JD_ROOT => {
+                if let Ok(m) = DOCS.lock() {
+                    if let Some(doc) = m.get(&instance_id) {
+                        match provider_kind() {
+                            ProviderKind::Serde => {
+                                if let Some(root_arc) = doc.root.as_ref().map(|r| Arc::clone(r)) {
+                                    let node_id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                                    if let Ok(mut nn) = NODES.lock() { nn.insert(node_id, NodeRep::Serde(root_arc)); }
+                                    return write_tlv_handle(T_JSON_NODE, node_id, result, result_len);
+                                }
+                                return E_PLUGIN;
+                            }
+                            ProviderKind::Yyjson => {
+                                if let Some(dp) = doc.doc_ptr {
+                                    let vp = nyjson_doc_root(dp as *mut c_void);
+                                    let node_id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                                    if let Ok(mut nn) = NODES.lock() { nn.insert(node_id, NodeRep::Yy { doc_id: instance_id, ptr: vp as usize }); }
+                                    return write_tlv_handle(T_JSON_NODE, node_id, result, result_len);
+                                }
+                                return E_PLUGIN;
+                            }
+                        }
+                    }
+                }
+                return E_PLUGIN;
+            }
+            JD_ERROR => {
+                if let Ok(m) = DOCS.lock() {
+                    if let Some(doc) = m.get(&instance_id) {
+                        let s = doc.last_err.clone().unwrap_or_default();
+                        return write_tlv_string(&s, result, result_len);
+                    } else {
+                        return E_HANDLE;
+                    }
+                } else {
+                    return E_PLUGIN;
+                }
+            }
+            JD_FINI => {
+                if let Ok(mut m) = DOCS.lock() {
+                    if let Some(mut di) = m.remove(&instance_id) {
+                        if let Some(dp) = di.doc_ptr.take() { nyjson_doc_free(dp as *mut c_void); }
+                    }
+                }
+                return write_tlv_void(result, result_len);
+            }
+            _ => E_METHOD,
+        }
+    }
+}
+
+#[no_mangle]
+pub static nyash_typebox_JsonDocBox: NyashTypeBoxFfi = NyashTypeBoxFfi {
+    abi_tag: 0x54594258, // 'TYBX'
+    version: 1,
+    struct_size: std::mem::size_of::<NyashTypeBoxFfi>() as u16,
+    name: b"JsonDocBox\0".as_ptr() as *const c_char,
+    resolve: Some(jsondoc_resolve),
+    invoke_id: Some(jsondoc_invoke_id),
+    capabilities: 0,
+};
+
+// ---- JsonNodeBox ----
+extern "C" fn jsonnode_resolve(name: *const c_char) -> u32 {
+    if name.is_null() {
+        return 0;
+    }
+    let s = unsafe { CStr::from_ptr(name) }.to_string_lossy();
+    match s.as_ref() {
+        "birth" => JN_BIRTH,
+        "kind" => JN_KIND,
+        "get" => JN_GET,
+        "size" => JN_SIZE,
+        "at" => JN_AT,
+        "str" => JN_STR,
+        "int" => JN_INT,
+        "bool" => JN_BOOL,
+        _ => 0,
+    }
+}
+
+extern "C" fn jsonnode_invoke_id(
+    instance_id: u32,
+    method_id: u32,
+    args: *const u8,
+    args_len: usize,
+    result: *mut u8,
+    result_len: *mut usize,
+) -> i32 {
+    unsafe {
+        let node_rep = match NODES.lock() {
+            Ok(m) => match m.get(&instance_id) { Some(v) => v.clone(), None => return E_HANDLE },
+            Err(_) => return E_PLUGIN,
+        };
+        match method_id {
+            JN_BIRTH => {
+                let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                if let Ok(mut m) = NODES.lock() { m.insert(id, NodeRep::Serde(Arc::new(Value::Null))); } else { return E_PLUGIN; }
+                return write_u32(id, result, result_len);
+            }
+            JN_KIND => {
+                match provider_kind() {
+                    ProviderKind::Serde => {
+                        let k = match node_rep { NodeRep::Serde(ref a) => match &**a {
+                            Value::Null => "null",
+                            Value::Bool(_) => "bool",
+                            Value::Number(n) => { if n.is_i64() { "int" } else { "real" } },
+                            Value::String(_) => "string",
+                            Value::Array(_) => "array",
+                            Value::Object(_) => "object",
+                        }, _ => "null"};
+                        write_tlv_string(k, result, result_len)
+                    }
+                    ProviderKind::Yyjson => {
+                        let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() };
+                        let k = if v.is_null() { "null" }
+                                else if nyjson_is_obj(v) != 0 { "object" }
+                                else if nyjson_is_arr(v) != 0 { "array" }
+                                else if nyjson_is_str(v) != 0 { "string" }
+                                else if nyjson_is_int(v) != 0 { "int" }
+                                else if nyjson_is_real(v) != 0 { "real" }
+                                else if nyjson_is_bool(v) != 0 { "bool" }
+                                else { "null" };
+                        write_tlv_string(k, result, result_len)
+                    }
+                }
+            }
+            JN_GET => {
+                let key = match read_arg_string(args, args_len, 0) { Some(s) => s, None => return E_ARGS };
+                match provider_kind() {
+                    ProviderKind::Serde => {
+                        let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                        if let NodeRep::Serde(ref a) = node_rep {
+                            if let Value::Object(map) = &**a {
+                                if let Some(child) = map.get(&key) {
+                                    if let Ok(mut mm) = NODES.lock() { mm.insert(id, NodeRep::Serde(Arc::new(child.clone()))); }
+                                    return write_tlv_handle(T_JSON_NODE, id, result, result_len);
+                                }
+                            }
+                        }
+                        if let Ok(mut mm) = NODES.lock() { mm.insert(id, NodeRep::Serde(Arc::new(Value::Null))); }
+                        write_tlv_handle(T_JSON_NODE, id, result, result_len)
+                    }
+                    ProviderKind::Yyjson => {
+                        let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() };
+                        let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                        let mut out_ptr: *mut c_void = std::ptr::null_mut();
+                        if !v.is_null() && nyjson_is_obj(v) != 0 {
+                            let c = CString::new(key).unwrap_or_default();
+                            out_ptr = nyjson_obj_get_key(v, c.as_ptr());
+                        }
+                        let doc_id = if let NodeRep::Yy { doc_id, .. } = node_rep { doc_id } else { 0 };
+                        let rep = if out_ptr.is_null() {
+                            NodeRep::Yy { doc_id, ptr: 0 }
+                        } else {
+                            NodeRep::Yy { doc_id, ptr: out_ptr as usize }
+                        };
+                        if let Ok(mut mm) = NODES.lock() { mm.insert(id, rep); }
+                        write_tlv_handle(T_JSON_NODE, id, result, result_len)
+                    }
+                }
+            }
+            JN_SIZE => {
+                match provider_kind() {
+                    ProviderKind::Serde => {
+                        let n = match node_rep { NodeRep::Serde(ref a) => match &**a { Value::Array(a) => a.len() as i64, Value::Object(o) => o.len() as i64, _ => 0 }, _ => 0 };
+                        write_tlv_i64(n, result, result_len)
+                    }
+                    ProviderKind::Yyjson => {
+                        let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() };
+                        let n = if !v.is_null() { if nyjson_is_arr(v) != 0 { nyjson_arr_size_val(v) as i64 } else if nyjson_is_obj(v) != 0 { nyjson_obj_size_val(v) as i64 } else { 0 } } else { 0 };
+                        write_tlv_i64(n, result, result_len)
+                    }
+                }
+            }
+            JN_AT => {
+                let idx = match read_arg_i64(args, args_len, 0) { Some(v) => v, None => return E_ARGS };
+                if idx < 0 { return E_ARGS; }
+                match provider_kind() {
+                    ProviderKind::Serde => {
+                        let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                        if let NodeRep::Serde(ref a) = node_rep {
+                            if let Value::Array(arr) = &**a {
+                                let i = idx as usize;
+                                if i < arr.len() { if let Ok(mut mm) = NODES.lock() { mm.insert(id, NodeRep::Serde(Arc::new(arr[i].clone()))); } return write_tlv_handle(T_JSON_NODE, id, result, result_len); }
+                            }
+                        }
+                        if let Ok(mut mm) = NODES.lock() { mm.insert(id, NodeRep::Serde(Arc::new(Value::Null))); }
+                        write_tlv_handle(T_JSON_NODE, id, result, result_len)
+                    }
+                    ProviderKind::Yyjson => {
+                        let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() };
+                        let id = NEXT_ID.fetch_add(1, Ordering::Relaxed);
+                        let mut child: *mut c_void = std::ptr::null_mut();
+                        if !v.is_null() && nyjson_is_arr(v) != 0 { child = nyjson_arr_get_val(v, idx as usize); }
+                        let doc_id = if let NodeRep::Yy { doc_id, .. } = node_rep { doc_id } else { 0 };
+                        let rep = if child.is_null() {
+                            NodeRep::Yy { doc_id, ptr: 0 }
+                        } else {
+                            NodeRep::Yy { doc_id, ptr: child as usize }
+                        };
+                        if let Ok(mut mm) = NODES.lock() { mm.insert(id, rep); }
+                        write_tlv_handle(T_JSON_NODE, id, result, result_len)
+                    }
+                }
+            }
+            JN_STR => match provider_kind() {
+                ProviderKind::Serde => {
+                    if let NodeRep::Serde(ref a) = node_rep { match &**a { Value::String(s) => write_tlv_string(s, result, result_len), Value::Object(o) => { if let Some(Value::String(s)) = o.get("value") { write_tlv_string(s, result, result_len) } else { write_tlv_string("", result, result_len) } }, _ => write_tlv_string("", result, result_len) } } else { write_tlv_string("", result, result_len) }
+                }
+                ProviderKind::Yyjson => {
+                    let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() };
+                    if !v.is_null() && nyjson_is_str(v) != 0 { let s = nyjson_get_str_val(v); if s.is_null() { write_tlv_string("", result, result_len) } else { let rs = CStr::from_ptr(s).to_string_lossy().to_string(); write_tlv_string(&rs, result, result_len) } }
+                    else if !v.is_null() && nyjson_is_obj(v) != 0 { let key = CString::new("value").unwrap(); let child = nyjson_obj_get_key(v, key.as_ptr()); if !child.is_null() && nyjson_is_str(child) != 0 { let s = nyjson_get_str_val(child); if s.is_null() { write_tlv_string("", result, result_len) } else { let rs = CStr::from_ptr(s).to_string_lossy().to_string(); write_tlv_string(&rs, result, result_len) } } else { write_tlv_string("", result, result_len) } }
+                    else { write_tlv_string("", result, result_len) }
+                }
+            },
+            JN_INT => match provider_kind() {
+                ProviderKind::Serde => {
+                    if let NodeRep::Serde(ref a) = node_rep { match &**a { Value::Number(n) => write_tlv_i64(n.as_i64().unwrap_or(0), result, result_len), Value::Object(o) => { if let Some(Value::Number(n)) = o.get("value") { write_tlv_i64(n.as_i64().unwrap_or(0), result, result_len) } else { write_tlv_i64(0, result, result_len) } }, _ => write_tlv_i64(0, result, result_len) } } else { write_tlv_i64(0, result, result_len) }
+                }
+                ProviderKind::Yyjson => {
+                    let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() };
+                    if !v.is_null() && nyjson_is_int(v) != 0 { write_tlv_i64(nyjson_get_sint_val(v) as i64, result, result_len) }
+                    else if !v.is_null() && nyjson_is_obj(v) != 0 { let key = CString::new("value").unwrap(); let child = nyjson_obj_get_key(v, key.as_ptr()); if !child.is_null() && nyjson_is_int(child) != 0 { write_tlv_i64(nyjson_get_sint_val(child) as i64, result, result_len) } else { write_tlv_i64(0, result, result_len) } }
+                    else { write_tlv_i64(0, result, result_len) }
+                }
+            },
+            JN_BOOL => match provider_kind() {
+                ProviderKind::Serde => { if let NodeRep::Serde(ref a) = node_rep { if let Value::Bool(b) = **a { write_tlv_bool(b, result, result_len) } else { write_tlv_bool(false, result, result_len) } } else { write_tlv_bool(false, result, result_len) } }
+                ProviderKind::Yyjson => { let v = if let NodeRep::Yy { ptr, .. } = node_rep { ptr as *mut c_void } else { std::ptr::null_mut() }; if !v.is_null() && nyjson_is_bool(v) != 0 { write_tlv_bool(nyjson_get_bool_val(v) != 0, result, result_len) } else { write_tlv_bool(false, result, result_len) } }
+            },
+            _ => E_METHOD,
+        }
+    }
+}
+
+#[no_mangle]
+pub static nyash_typebox_JsonNodeBox: NyashTypeBoxFfi = NyashTypeBoxFfi {
+    abi_tag: 0x54594258, // 'TYBX'
+    version: 1,
+    struct_size: std::mem::size_of::<NyashTypeBoxFfi>() as u16,
+    name: b"JsonNodeBox\0".as_ptr() as *const c_char,
+    resolve: Some(jsonnode_resolve),
+    invoke_id: Some(jsonnode_invoke_id),
+    capabilities: 0,
+};
+
+// ---- TLV helpers (copied/minimized) ----
+fn preflight(result: *mut u8, result_len: *mut usize, needed: usize) -> bool {
+    unsafe {
+        if result_len.is_null() {
+            return false;
+        }
+        if result.is_null() || *result_len < needed {
+            *result_len = needed;
+            return true;
+        }
+    }
+    false
+}
+fn write_tlv_result(payloads: &[(u8, &[u8])], result: *mut u8, result_len: *mut usize) -> i32 {
+    if result_len.is_null() {
+        return E_ARGS;
+    }
+    let mut buf: Vec<u8> =
+        Vec::with_capacity(4 + payloads.iter().map(|(_, p)| 4 + p.len()).sum::<usize>());
+    buf.extend_from_slice(&1u16.to_le_bytes());
+    buf.extend_from_slice(&(payloads.len() as u16).to_le_bytes());
+    for (tag, payload) in payloads {
+        buf.push(*tag);
+        buf.push(0);
+        buf.extend_from_slice(&(payload.len() as u16).to_le_bytes());
+        buf.extend_from_slice(payload);
+    }
+    unsafe {
+        let needed = buf.len();
+        if result.is_null() || *result_len < needed {
+            *result_len = needed;
+            return E_SHORT;
+        }
+        std::ptr::copy_nonoverlapping(buf.as_ptr(), result, needed);
+        *result_len = needed;
+    }
+    OK
+}
+fn write_u32(v: u32, result: *mut u8, result_len: *mut usize) -> i32 {
+    if result_len.is_null() {
+        return E_ARGS;
+    }
+    unsafe {
+        if result.is_null() || *result_len < 4 {
+            *result_len = 4;
+            return E_SHORT;
+        }
+        let b = v.to_le_bytes();
+        std::ptr::copy_nonoverlapping(b.as_ptr(), result, 4);
+        *result_len = 4;
+    }
+    OK
+}
+fn write_tlv_void(result: *mut u8, result_len: *mut usize) -> i32 {
+    // Align with common helpers: use tag=9 for void/host-handle-like empty
+    write_tlv_result(&[(9u8, &[])], result, result_len)
+}
+fn write_tlv_i64(v: i64, result: *mut u8, result_len: *mut usize) -> i32 {
+    write_tlv_result(&[(3u8, &v.to_le_bytes())], result, result_len)
+}
+fn write_tlv_bool(v: bool, result: *mut u8, result_len: *mut usize) -> i32 {
+    write_tlv_result(&[(1u8, &[if v { 1u8 } else { 0u8 }])], result, result_len)
+}
+fn write_tlv_handle(
+    type_id: u32,
+    instance_id: u32,
+    result: *mut u8,
+    result_len: *mut usize,
+) -> i32 {
+    let mut payload = Vec::with_capacity(8);
+    payload.extend_from_slice(&type_id.to_le_bytes());
+    payload.extend_from_slice(&instance_id.to_le_bytes());
+    write_tlv_result(&[(8u8, &payload)], result, result_len)
+}
+fn write_tlv_string(s: &str, result: *mut u8, result_len: *mut usize) -> i32 {
+    write_tlv_result(&[(6u8, s.as_bytes())], result, result_len)
+}
+fn read_arg_string(args: *const u8, args_len: usize, n: usize) -> Option<String> {
+    if args.is_null() || args_len < 4 {
+        return None;
+    }
+    let buf = unsafe { std::slice::from_raw_parts(args, args_len) };
+    let mut off = 4usize;
+    for i in 0..=n {
+        if buf.len() < off + 4 {
+            return None;
+        }
+        let tag = buf[off];
+        let size = u16::from_le_bytes([buf[off + 2], buf[off + 3]]) as usize;
+        if buf.len() < off + 4 + size {
+            return None;
+        }
+        if i == n {
+            if tag != 6 {
+                return None;
+            }
+            let s = String::from_utf8_lossy(&buf[off + 4..off + 4 + size]).to_string();
+            return Some(s);
+        }
+        off += 4 + size;
+    }
+    None
+}
+fn read_arg_i64(args: *const u8, args_len: usize, n: usize) -> Option<i64> {
+    if args.is_null() || args_len < 4 {
+        return None;
+    }
+    let buf = unsafe { std::slice::from_raw_parts(args, args_len) };
+    let mut off = 4usize;
+    for i in 0..=n {
+        if buf.len() < off + 4 {
+            return None;
+        }
+        let tag = buf[off];
+        let size = u16::from_le_bytes([buf[off + 2], buf[off + 3]]) as usize;
+        if buf.len() < off + 4 + size {
+            return None;
+        }
+        if i == n {
+            if tag != 3 || size != 8 {
+                return None;
+            }
+            let mut b = [0u8; 8];
+            b.copy_from_slice(&buf[off + 4..off + 12]);
+            return Some(i64::from_le_bytes(b));
+        }
+        off += 4 + size;
+    }
+    None
+}
--- a/src/llvm_py/pyvm/ops_box.py
+++ b/src/llvm_py/pyvm/ops_box.py
@ -22,6 +22,12 @@ def op_newbox(owner, inst: Dict[str, Any], regs: Dict[int, Any]) -> None:
        val = {"__box__": "ArrayBox", "__arr": []}
    elif btype == "MapBox":
        val = {"__box__": "MapBox", "__map": {}}
+    elif btype == "JsonDocBox":
+        # Minimal JsonDocBox (PyVM-only): stores parsed JSON and last error
+        val = {"__box__": "JsonDocBox", "__doc": None, "__err": None}
+    elif btype == "JsonNodeBox":
+        # Minimal JsonNodeBox with empty Null node
+        val = {"__box__": "JsonNodeBox", "__node": None}
    else:
        # Unknown box -> opaque
        val = {"__box__": btype}
@ -135,7 +141,10 @@ def op_boxcall(owner, fn, inst: Dict[str, Any], regs: Dict[int, Any]) -> None:
    # ArrayBox minimal methods
    elif isinstance(recv, dict) and recv.get("__box__") == "ArrayBox":
        arr = recv.get("__arr", [])
-        if method in ("len", "size"):
+        if method in ("birth",):
+            # No-op initializer for parity with Nyash VM
+            out = 0
+        elif method in ("len", "size"):
            out = len(arr)
        elif method == "get":
            idx = int(args[0]) if args else 0
@ -185,6 +194,87 @@ def op_boxcall(owner, fn, inst: Dict[str, Any], regs: Dict[int, Any]) -> None:
            out = None
        recv["__map"] = m

+    # JsonDocBox (PyVM-native shim)
+    elif isinstance(recv, dict) and recv.get("__box__") == "JsonDocBox":
+        import json
+        if method == "parse":
+            s = args[0] if args else ""
+            try:
+                recv["__doc"] = json.loads(str(s))
+                recv["__err"] = None
+            except Exception as e:
+                recv["__doc"] = None
+                recv["__err"] = str(e)
+            out = 0
+        elif method == "root":
+            out = {"__box__": "JsonNodeBox", "__node": recv.get("__doc", None)}
+        elif method == "error":
+            out = recv.get("__err") or ""
+        else:
+            out = None
+
+    # JsonNodeBox (PyVM-native shim)
+    elif isinstance(recv, dict) and recv.get("__box__") == "JsonNodeBox":
+        node = recv.get("__node", None)
+        if method == "kind":
+            if node is None:
+                out = "null"
+            elif isinstance(node, bool):
+                out = "bool"
+            elif isinstance(node, int):
+                out = "int"
+            elif isinstance(node, float):
+                out = "real"
+            elif isinstance(node, str):
+                out = "string"
+            elif isinstance(node, list):
+                out = "array"
+            elif isinstance(node, dict):
+                out = "object"
+            else:
+                out = "null"
+        elif method == "get":
+            key = str(args[0]) if args else ""
+            if isinstance(node, dict) and key in node:
+                out = {"__box__": "JsonNodeBox", "__node": node.get(key)}
+            else:
+                out = {"__box__": "JsonNodeBox", "__node": None}
+        elif method == "size":
+            if isinstance(node, list):
+                out = len(node)
+            elif isinstance(node, dict):
+                out = len(node)
+            else:
+                out = 0
+        elif method == "at":
+            try:
+                idx = int(args[0]) if args else 0
+            except Exception:
+                idx = 0
+            if isinstance(node, list) and 0 <= idx < len(node):
+                out = {"__box__": "JsonNodeBox", "__node": node[idx]}
+            else:
+                out = {"__box__": "JsonNodeBox", "__node": None}
+        elif method == "str":
+            if isinstance(node, str):
+                out = node
+            elif isinstance(node, dict) and isinstance(node.get("value"), str):
+                out = node.get("value")
+            else:
+                out = ""
+        elif method == "int":
+            if isinstance(node, int):
+                out = node
+            elif isinstance(node, dict):
+                v = node.get("value")
+                out = int(v) if isinstance(v, int) else 0
+            else:
+                out = 0
+        elif method == "bool":
+            out = bool(node) if isinstance(node, bool) else False
+        else:
+            out = None
+
    elif method == "esc_json":
        s = args[0] if args else ""
        s = "" if s is None else str(s)
@ -236,4 +326,3 @@ def op_boxcall(owner, fn, inst: Dict[str, Any], regs: Dict[int, Any]) -> None:
        out = None

    owner._set(regs, inst.get("dst"), out)
-
--- a/src/runtime/plugin_loader_unified.rs
+++ b/src/runtime/plugin_loader_unified.rs
@ -94,16 +94,22 @@ impl PluginHost {
        let box_conf = cfg
            .get_box_config(lib_name, box_type, &toml_value)
            .ok_or(BidError::InvalidType)?;
-        let m = box_conf
-            .methods
-            .get(method_name)
-            .ok_or(BidError::InvalidMethod)?;
+        // Prefer config mapping; fallback to loader's TypeBox resolve(name)
+        let (method_id, returns_result) = if let Some(m) = box_conf.methods.get(method_name) {
+            (m.method_id, m.returns_result)
+        } else {
+            let l = self.loader.read().unwrap();
+            let mid = l
+                .resolve_method_id(box_type, method_name)
+                .map_err(|_| BidError::InvalidMethod)?;
+            (mid, false)
+        };
        Ok(MethodHandle {
            lib: lib_name.to_string(),
            box_type: box_type.to_string(),
            type_id: box_conf.type_id,
-            method_id: m.method_id,
-            returns_result: m.returns_result,
+            method_id,
+            returns_result,
        })
    }

--- a/src/runtime/plugin_loader_v2/enabled/loader.rs
+++ b/src/runtime/plugin_loader_v2/enabled/loader.rs
@ -23,6 +23,8 @@ struct LoadedBoxSpec {
    fini_method_id: Option<u32>,
    // Optional Nyash ABI v2 per-box invoke entry (not yet used for calls)
    invoke_id: Option<BoxInvokeFn>,
+    // Optional resolve(name)->method_id provided by NyashTypeBoxFfi
+    resolve_fn: Option<extern "C" fn(*const std::os::raw::c_char) -> u32>,
 }
 #[derive(Debug, Clone, Copy)]
 struct MethodSpec {
@ -172,7 +174,7 @@ impl PluginLoaderV2 {
                        }
                        continue;
                    }
-                    // Remember invoke_id in box_specs for (lib_name, box_type)
+                    // Remember invoke_id/resolve in box_specs for (lib_name, box_type)
                    if let Some(invoke_id) = st.invoke_id {
                        let key = (lib_name.to_string(), box_type.to_string());
                        let mut map = self.box_specs.write().map_err(|_| BidError::PluginError)?;
@ -181,8 +183,10 @@ impl PluginLoaderV2 {
                            methods: HashMap::new(),
                            fini_method_id: None,
                            invoke_id: None,
+                            resolve_fn: None,
                        });
                        entry.invoke_id = Some(invoke_id);
+                        entry.resolve_fn = st.resolve;
                    } else if dbg_on() {
                        eprintln!(
                            "[PluginLoaderV2] WARN: TypeBox present but no invoke_id for {}.{} — plugin should export per-Box invoke",
@ -311,6 +315,56 @@ impl PluginLoaderV2 {
        })
    }

+    /// Resolve method_id for (box_type, method_name), consulting config first, then TypeBox resolve() if available.
+    pub(crate) fn resolve_method_id(&self, box_type: &str, method_name: &str) -> BidResult<u32> {
+        use std::ffi::CString;
+        let cfg = self.config.as_ref().ok_or(BidError::PluginError)?;
+        let cfg_path = self.config_path.as_deref().unwrap_or("nyash.toml");
+        let toml_value: toml::Value = super::errors::from_toml(toml::from_str(
+            &std::fs::read_to_string(cfg_path).map_err(|_| BidError::PluginError)?,
+        ))?;
+        // 1) config mapping
+        if let Some((lib_name, _)) = cfg.find_library_for_box(box_type) {
+            if let Some(bc) = cfg.get_box_config(&lib_name, box_type, &toml_value) {
+                if let Some(m) = bc.methods.get(method_name) {
+                    return Ok(m.method_id);
+                }
+            }
+            // 2) v2 TypeBox resolve (and cache)
+            let key = (lib_name.to_string(), box_type.to_string());
+            if let Ok(mut map) = self.box_specs.write() {
+                if let Some(spec) = map.get_mut(&key) {
+                    if let Some(ms) = spec.methods.get(method_name) {
+                        return Ok(ms.method_id);
+                    }
+                    if let Some(res_fn) = spec.resolve_fn {
+                        if let Ok(cstr) = CString::new(method_name) {
+                            let mid = res_fn(cstr.as_ptr());
+                            if mid != 0 {
+                                // Cache minimal MethodSpec (returns_result unknown → false)
+                                spec.methods.insert(
+                                    method_name.to_string(),
+                                    MethodSpec {
+                                        method_id: mid,
+                                        returns_result: false,
+                                    },
+                                );
+                                if dbg_on() {
+                                    eprintln!(
+                                        "[PluginLoaderV2] resolve(name) {}.{} -> id {}",
+                                        box_type, method_name, mid
+                                    );
+                                }
+                                return Ok(mid);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        Err(BidError::InvalidMethod)
+    }
+
    pub fn construct_existing_instance(
        &self,
        type_id: u32,
@ -634,10 +688,19 @@ impl PluginLoaderV2 {
            .get_box_config(lib_name, box_type, &toml_value)
            .ok_or(BidError::InvalidType)?;
        let type_id = box_conf.type_id;
-        let method = box_conf
-            .methods
-            .get(method_name)
-            .ok_or(BidError::InvalidMethod)?;
+        // Resolve method id via config or TypeBox resolve()
+        let method_id = match self.resolve_method_id(box_type, method_name) {
+            Ok(mid) => mid,
+            Err(e) => {
+                if dbg_on() {
+                    eprintln!(
+                        "[PluginLoaderV2] ERR: method resolve failed for {}.{}: {:?}",
+                        box_type, method_name, e
+                    );
+                }
+                return Err(BidError::InvalidMethod);
+            }
+        };
        // Get plugin handle
        let plugins = self.plugins.read().map_err(|_| BidError::PluginError)?;
        let _plugin = plugins.get(lib_name).ok_or(BidError::PluginError)?;
@ -646,7 +709,7 @@ impl PluginLoaderV2 {
        let (_code, out_len, out) = super::host_bridge::invoke_alloc(
            super::super::nyash_plugin_invoke_v2_shim,
            type_id,
-            method.method_id,
+            method_id,
            instance_id,
            &tlv,
        );
--- a/tools/test/smoke/selfhost/collect_prints_mixed.sh
+++ b/tools/test/smoke/selfhost/collect_prints_mixed.sh
@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT_DIR=$(cd "$(dirname "$0")/../../../.." && pwd)
+
+echo "[smoke] collect_prints mixed order ..." >&2
+
+pushd "$ROOT_DIR" >/dev/null
+
+cargo build --release -q
+
+export NYASH_ENABLE_USING=1
+export NYASH_VM_USE_PY=1
+BIN=./target/release/nyash
+# Use JSON Box based app to avoid reliance on MiniVmPrints fallbacks
+APP=apps/tests/jsonbox_collect_prints_smoke.nyash
+
+out=$("$BIN" --backend vm "$APP")
+
+expected=$'A\nB\n7\n1\n7\n5'
+
+if [[ "$out" != "$expected" ]]; then
+  echo "[smoke] FAIL: unexpected output" >&2
+  echo "--- got ---" >&2
+  printf '%s\n' "$out" >&2
+  echo "--- exp ---" >&2
+  printf '%s\n' "$expected" >&2
+  exit 1
+fi
+
+echo "[smoke] OK: collect_prints mixed order" >&2
+popd >/dev/null
--- a/tools/test/smoke/selfhost/jsonbox_collect_prints.sh
+++ b/tools/test/smoke/selfhost/jsonbox_collect_prints.sh
@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT_DIR=$(cd "$(dirname "$0")/../../../.." && pwd)
+
+echo "[smoke] jsonbox collect_prints ..." >&2
+
+pushd "$ROOT_DIR" >/dev/null
+
+cargo build --release -q --manifest-path plugins/nyash-json-plugin/Cargo.toml
+
+export NYASH_VM_USE_PY=1
+export NYASH_LOAD_NY_PLUGINS=1
+unset NYASH_DISABLE_PLUGINS || true
+
+BIN=./target/release/nyash
+APP=apps/tests/jsonbox_collect_prints_smoke.nyash
+
+out=$("$BIN" --backend vm "$APP")
+expected=$'A\nB\n7\n1\n7\n5'
+
+if [[ "$out" != "$expected" ]]; then
+  echo "[smoke] FAIL: unexpected output" >&2
+  echo "--- got ---" >&2
+  printf '%s\n' "$out" >&2
+  echo "--- exp ---" >&2
+  printf '%s\n' "$expected" >&2
+  exit 1
+fi
+
+echo "[smoke] OK: jsonbox collect_prints" >&2
+popd >/dev/null
--- a/tools/test/smoke/selfhost/jsonbox_nested.sh
+++ b/tools/test/smoke/selfhost/jsonbox_nested.sh
@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT_DIR=$(cd "$(dirname "$0")/../../../.." && pwd)
+
+echo "[smoke] jsonbox nested ..." >&2
+pushd "$ROOT_DIR" >/dev/null
+
+cargo build --release -q --manifest-path plugins/nyash-json-plugin/Cargo.toml
+
+export NYASH_VM_USE_PY=1
+export NYASH_LOAD_NY_PLUGINS=1
+
+BIN=./target/release/nyash
+APP=apps/tests/jsonbox_nested.nyash
+
+out=$("$BIN" --backend vm "$APP")
+expected=$'B\n7\n3\n2'
+
+if [[ "$out" != "$expected" ]]; then
+  echo "[smoke] FAIL: unexpected output" >&2
+  echo "--- got ---" >&2
+  printf '%s\n' "$out" >&2
+  echo "--- exp ---" >&2
+  printf '%s\n' "$expected" >&2
+  exit 1
+fi
+
+echo "[smoke] OK: jsonbox nested" >&2
+popd >/dev/null
+
--- a/tools/test/smoke/selfhost/jsonbox_parse_err.sh
+++ b/tools/test/smoke/selfhost/jsonbox_parse_err.sh
@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT_DIR=$(cd "$(dirname "$0")/../../../.." && pwd)
+
+echo "[smoke] jsonbox parse ERR ..." >&2
+pushd "$ROOT_DIR" >/dev/null
+
+cargo build --release -q --manifest-path plugins/nyash-json-plugin/Cargo.toml
+
+export NYASH_VM_USE_PY=1
+export NYASH_LOAD_NY_PLUGINS=1
+
+BIN=./target/release/nyash
+APP=apps/tests/jsonbox_parse_err.nyash
+
+out=$("$BIN" --backend vm "$APP")
+expected=$'ERR'
+
+if [[ "$out" != "$expected" ]]; then
+  echo "[smoke] FAIL: unexpected output" >&2
+  echo "--- got ---" >&2
+  printf '%s\n' "$out" >&2
+  echo "--- exp ---" >&2
+  printf '%s\n' "$expected" >&2
+  exit 1
+fi
+
+echo "[smoke] OK: jsonbox parse ERR" >&2
+popd >/dev/null
+
--- a/tools/test/smoke/selfhost/jsonbox_parse_ok.sh
+++ b/tools/test/smoke/selfhost/jsonbox_parse_ok.sh
@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+ROOT_DIR=$(cd "$(dirname "$0")/../../../.." && pwd)
+
+echo "[smoke] jsonbox parse OK ..." >&2
+pushd "$ROOT_DIR" >/dev/null
+
+cargo build --release -q --manifest-path plugins/nyash-json-plugin/Cargo.toml
+
+export NYASH_VM_USE_PY=1
+export NYASH_LOAD_NY_PLUGINS=1
+
+BIN=./target/release/nyash
+APP=apps/tests/jsonbox_parse_ok.nyash
+
+out=$("$BIN" --backend vm "$APP")
+expected=$'Program'
+
+if [[ "$out" != "$expected" ]]; then
+  echo "[smoke] FAIL: unexpected output" >&2
+  echo "--- got ---" >&2
+  printf '%s\n' "$out" >&2
+  echo "--- exp ---" >&2
+  printf '%s\n' "$expected" >&2
+  exit 1
+fi
+
+echo "[smoke] OK: jsonbox parse OK" >&2
+popd >/dev/null
+