diff --git a/editor/CMakeLists.txt b/editor/CMakeLists.txt
index 32c9e24..5a0f648 100644
--- a/editor/CMakeLists.txt
+++ b/editor/CMakeLists.txt
@@ -11039,3 +11039,18 @@ target_include_directories(step1941_test PRIVATE src)
 
 add_executable(step1942_test tests/step1942_test.cpp)
 target_include_directories(step1942_test PRIVATE src)
+
+add_executable(step1943_test tests/step1943_test.cpp)
+target_include_directories(step1943_test PRIVATE src)
+
+add_executable(step1944_test tests/step1944_test.cpp)
+target_include_directories(step1944_test PRIVATE src)
+
+add_executable(step1945_test tests/step1945_test.cpp)
+target_include_directories(step1945_test PRIVATE src)
+
+add_executable(step1946_test tests/step1946_test.cpp)
+target_include_directories(step1946_test PRIVATE src)
+
+add_executable(step1947_test tests/step1947_test.cpp)
+target_include_directories(step1947_test PRIVATE src)
diff --git a/editor/src/PipelineExecutionPlan.h b/editor/src/PipelineExecutionPlan.h
new file mode 100644
index 0000000..de7f46e
--- /dev/null
+++ b/editor/src/PipelineExecutionPlan.h
@@ -0,0 +1,56 @@
+#pragma once
+#include "PipelineGraph.h"
+#include "PipelineStageSpec.h"
+#include <string>
+#include <vector>
+
+namespace whetstone {
+
+class PipelineExecutionPlan {
+public:
+    void addStage(const PipelineStageSpec& spec) {
+        registry_.registerStage(spec);
+        graph_.addStage(spec.stageId);
+    }
+
+    void addEdge(const std::string& fromId, const std::string& toId) {
+        graph_.addEdge(fromId, toId);
+    }
+
+    // Stages in topological order.
+    std::vector<PipelineStageSpec> executionOrder() const {
+        std::vector<PipelineStageSpec> result;
+        for (const auto& id : graph_.topologicalOrder())
+            result.push_back(registry_.getStage(id));
+        return result;
+    }
+
+    // Language per stage in execution order.
+    std::vector<std::string> languageSequence() const {
+        std::vector<std::string> langs;
+        for (const auto& spec : executionOrder())
+            langs.push_back(spec.language);
+        return langs;
+    }
+
+    bool isValid() const {
+        return !graph_.hasCycle() && graph_.stageCount() > 0;
+    }
+
+    // Pairs "langA->langB" wherever adjacent stages in execution order differ in language.
+    std::vector<std::string> boundaryPairs() const {
+        auto order = executionOrder();
+        std::vector<std::string> pairs;
+        for (std::size_t i = 1; i < order.size(); ++i) {
+            if (order[i-1].language != order[i].language)
+                pairs.push_back(order[i-1].language + "->" + order[i].language);
+        }
+        return pairs;
+    }
+
+private:
+    PipelineStageRegistry registry_;
+    PipelineGraph         graph_;
+};
+
+} // namespace whetstone
diff --git a/editor/src/PipelineGraph.h b/editor/src/PipelineGraph.h
new file mode 100644
index 0000000..c966fb5
--- /dev/null
+++ b/editor/src/PipelineGraph.h
@@ -0,0 +1,84 @@
+#pragma once
+#include <map>
+#include <queue>
+#include <set>
+#include <string>
+#include <vector>
+
+namespace whetstone {
+
+class PipelineGraph {
+public:
+    void addStage(const std::string& stageId) {
+        // Ensure entry exists even with no edges.
+        succ_[stageId];
+        pred_[stageId];
+    }
+
+    void addEdge(const std::string& fromId, const std::string& toId) {
+        succ_[fromId].push_back(toId);
+        pred_[toId].push_back(fromId);
+        // Ensure reverse entries exist.
+        succ_[toId];
+        pred_[fromId];
+    }
+
+    std::vector<std::string> successors(const std::string& stageId) const {
+        auto it = succ_.find(stageId);
+        return it == succ_.end() ? std::vector<std::string>{} : it->second;
+    }
+
+    std::vector<std::string> predecessors(const std::string& stageId) const {
+        auto it = pred_.find(stageId);
+        return it == pred_.end() ? std::vector<std::string>{} : it->second;
+    }
+
+    // Kahn's algorithm. Returns empty if cycle detected.
+    std::vector<std::string> topologicalOrder() const {
+        // Build in-degree map.
+        std::map<std::string, int> indegree;
+        for (const auto& [id, _] : succ_) indegree[id] = 0;
+        for (const auto& [id, preds] : pred_)
+            indegree[id] = static_cast<int>(preds.size());
+
+        std::queue<std::string> q;
+        for (const auto& [id, deg] : indegree)
+            if (deg == 0) q.push(id);
+
+        std::vector<std::string> order;
+        while (!q.empty()) {
+            auto cur = q.front(); q.pop();
+            order.push_back(cur);
+            for (const auto& s : successors(cur)) {
+                if (--indegree[s] == 0) q.push(s);
+            }
+        }
+        // If we didn't visit all nodes, there's a cycle.
+        if (order.size() != succ_.size()) return {};
+        return order;
+    }
+
+    bool hasCycle() const { return topologicalOrder().empty() && !succ_.empty(); }
+
+    std::vector<std::string> sourceStages() const {
+        std::vector<std::string> result;
+        for (const auto& [id, preds] : pred_)
+            if (preds.empty()) result.push_back(id);
+        return result;
+    }
+
+    std::vector<std::string> sinkStages() const {
+        std::vector<std::string> result;
+        for (const auto& [id, succs] : succ_)
+            if (succs.empty()) result.push_back(id);
+        return result;
+    }
+
+    int stageCount() const { return static_cast<int>(succ_.size()); }
+
+private:
+    std::map<std::string, std::vector<std::string>> succ_;
+    std::map<std::string, std::vector<std::string>> pred_;
+};
+
+} // namespace whetstone
diff --git a/editor/src/PipelineParityValidator.h b/editor/src/PipelineParityValidator.h
new file mode 100644
index 0000000..03c9d97
--- /dev/null
+++ b/editor/src/PipelineParityValidator.h
@@ -0,0 +1,57 @@
+#pragma once
+#include <map>
+#include <string>
+#include <vector>
+
+namespace whetstone {
+
+struct StageOutput {
+    std::string stageId;
+    std::string language;
+    std::string output;
+    bool        success = true;
+};
+
+class PipelineParityValidator {
+public:
+    void setReference(const std::string& stageId, const std::string& output) {
+        references_[stageId] = output;
+    }
+
+    struct ValidationResult {
+        bool                     passed = true;
+        std::vector<std::string> failedStages;
+    };
+
+    // For each StageOutput: fail if success=false OR (reference set AND output != reference).
+    ValidationResult validate(const std::vector<StageOutput>& outputs) const {
+        ValidationResult result;
+        for (const auto& so : outputs) {
+            bool fail = !so.success;
+            if (!fail) {
+                auto it = references_.find(so.stageId);
+                if (it != references_.end() && so.output != it->second)
+                    fail = true;
+            }
+            if (fail) {
+                result.passed = false;
+                result.failedStages.push_back(so.stageId);
+            }
+        }
+        return result;
+    }
+
+    // True if output matches reference, or no reference set for this stage.
+    bool stagePass(const std::string& stageId, const std::string& output) const {
+        auto it = references_.find(stageId);
+        if (it == references_.end()) return true;
+        return output == it->second;
+    }
+
+    int referenceCount() const { return static_cast<int>(references_.size()); }
+
+private:
+    std::map<std::string, std::string> references_;
+};
+
+} // namespace whetstone
diff --git a/editor/src/PipelineStageSpec.h b/editor/src/PipelineStageSpec.h
new file mode 100644
index 0000000..dc50f68
--- /dev/null
+++ b/editor/src/PipelineStageSpec.h
@@ -0,0 +1,53 @@
+#pragma once
+#include <map>
+#include <stdexcept>
+#include <string>
+#include <vector>
+
+namespace whetstone {
+
+struct PipelineStageSpec {
+    std::string stageId;
+    std::string language;
+    std::string description;
+    std::string inputType;
+    std::string outputType;
+};
+
+class PipelineStageRegistry {
+public:
+    void registerStage(const PipelineStageSpec& spec) {
+        stages_[spec.stageId] = spec;
+    }
+
+    PipelineStageSpec getStage(const std::string& stageId) const {
+        auto it = stages_.find(stageId);
+        if (it == stages_.end())
+            throw std::out_of_range("stage not found: " + stageId);
+        return it->second;
+    }
+
+    bool hasStage(const std::string& stageId) const {
+        return stages_.count(stageId) > 0;
+    }
+
+    std::vector<std::string> stageIds() const {
+        std::vector<std::string> ids;
+        for (const auto& [id, _] : stages_) ids.push_back(id);
+        return ids;
+    }
+
+    std::vector<PipelineStageSpec> stagesForLanguage(const std::string& language) const {
+        std::vector<PipelineStageSpec> result;
+        for (const auto& [_, spec] : stages_)
+            if (spec.language == language) result.push_back(spec);
+        return result;
+    }
+
+    int stageCount() const { return static_cast<int>(stages_.size()); }
+
+private:
+    std::map<std::string, PipelineStageSpec> stages_;
+};
+
+} // namespace whetstone
diff --git a/editor/src/Sprint283IntegrationSummary.h b/editor/src/Sprint283IntegrationSummary.h
new file mode 100644
index 0000000..a610a20
--- /dev/null
+++ b/editor/src/Sprint283IntegrationSummary.h
@@ -0,0 +1,21 @@
+#pragma once
+// Sprint 283 Integration Summary
+// Steps 1943–1947: poly-pipeline
+//
+//  1943: PipelineStageSpec + PipelineStageRegistry  — stage descriptors
+//  1944: PipelineGraph                              — DAG with Kahn topo sort
+//  1945: PipelineExecutionPlan                      — registry + graph combined
+//  1946: PipelineParityValidator                    — reference-output validation
+//  1947: Integration                                — 5-stage Python→TS pipeline
+
+#include <string>
+
+namespace whetstone {
+
+struct Sprint283IntegrationSummary {
+    int stepsCompleted = 5;
+    bool success       = true;
+    std::string sprintName() const { return "Sprint 283: poly-pipeline"; }
+};
+
+} // namespace whetstone
diff --git a/editor/tests/step1943_test.cpp b/editor/tests/step1943_test.cpp
new file mode 100644
index 0000000..5ba0fb4
--- /dev/null
+++ b/editor/tests/step1943_test.cpp
@@ -0,0 +1,86 @@
+// Step 1943: PipelineStageSpec + PipelineStageRegistry
+//
+//  t1: registerStage and hasStage/stageCount
+//  t2: getStage returns correct spec; throws for unknown
+//  t3: stageIds returns all registered ids
+//  t4: stagesForLanguage filters correctly
+//  t5: re-registering same id overwrites
+
+#include "PipelineStageSpec.h"
+#include <iostream>
+#include <stdexcept>
+
+namespace ws = whetstone;
+static int p=0,f=0;
+#define T(n) { std::cout<<"  "<<#n<<"... "; }
+#define P() { std::cout<<"PASS\n"; ++p; }
+#define F(m) { std::cout<<"FAIL: "<<m<<"\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+void t1(){
+    T(registerStage_and_metadata);
+    ws::PipelineStageRegistry r;
+    r.registerStage({"ingest","Python","CSV ingestion","csv","records"});
+    r.registerStage({"normalize","Rust","Normalization","records","normalized"});
+    C(r.stageCount() == 2,         "two stages");
+    C(r.hasStage("ingest"),        "has ingest");
+    C(r.hasStage("normalize"),     "has normalize");
+    C(!r.hasStage("unknown"),      "no unknown");
+    P();
+}
+
+void t2(){
+    T(getStage_correct_and_throws);
+    ws::PipelineStageRegistry r;
+    r.registerStage({"ingest","Python","CSV","csv","records"});
+    auto s = r.getStage("ingest");
+    C(s.stageId == "ingest",   "stageId");
+    C(s.language == "Python",  "language");
+    C(s.inputType == "csv",    "inputType");
+    bool threw = false;
+    try { r.getStage("missing"); } catch (const std::out_of_range&) { threw = true; }
+    C(threw, "throws for missing");
+    P();
+}
+
+void t3(){
+    T(stageIds_returns_all);
+    ws::PipelineStageRegistry r;
+    r.registerStage({"a","Python","","",""});
+    r.registerStage({"b","Rust","","",""});
+    r.registerStage({"c","Go","","",""});
+    auto ids = r.stageIds();
+    C(ids.size() == 3, "three ids");
+    P();
+}
+
+void t4(){
+    T(stagesForLanguage_filters);
+    ws::PipelineStageRegistry r;
+    r.registerStage({"ingest",  "Python","","",""});
+    r.registerStage({"validate","Python","","",""});
+    r.registerStage({"norm",    "Rust",  "","",""});
+    auto pyStages = r.stagesForLanguage("Python");
+    C(pyStages.size() == 2,               "two Python stages");
+    C(r.stagesForLanguage("Rust").size()==1,"one Rust stage");
+    C(r.stagesForLanguage("Go").empty(),   "no Go stages");
+    P();
+}
+
+void t5(){
+    T(re_register_overwrites);
+    ws::PipelineStageRegistry r;
+    r.registerStage({"s","Python","old","","old_out"});
+    r.registerStage({"s","Rust",  "new","","new_out"});
+    C(r.stageCount() == 1,                 "still one stage");
+    C(r.getStage("s").language == "Rust",  "overwritten to Rust");
+    C(r.getStage("s").outputType == "new_out","overwritten outputType");
+    P();
+}
+
+int main(){
+    std::cout << "Step 1943: PipelineStageSpec + PipelineStageRegistry\n";
+    t1(); t2(); t3(); t4(); t5();
+    std::cout << "\n" << p << "/" << (p+f) << " passed\n";
+    return f > 0 ? 1 : 0;
+}
diff --git a/editor/tests/step1944_test.cpp b/editor/tests/step1944_test.cpp
new file mode 100644
index 0000000..1b7267a
--- /dev/null
+++ b/editor/tests/step1944_test.cpp
@@ -0,0 +1,105 @@
+// Step 1944: PipelineGraph
+//
+//  t1: addStage and stageCount
+//  t2: addEdge; successors and predecessors
+//  t3: topologicalOrder on linear chain
+//  t4: hasCycle detects cycle; acyclic returns false
+//  t5: sourceStages and sinkStages
+
+#include "PipelineGraph.h"
+#include <algorithm>
+#include <iostream>
+
+namespace ws = whetstone;
+static int p=0,f=0;
+#define T(n) { std::cout<<"  "<<#n<<"... "; }
+#define P() { std::cout<<"PASS\n"; ++p; }
+#define F(m) { std::cout<<"FAIL: "<<m<<"\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+void t1(){
+    T(addStage_and_stageCount);
+    ws::PipelineGraph g;
+    g.addStage("a");
+    g.addStage("b");
+    g.addStage("c");
+    C(g.stageCount() == 3, "three stages");
+    P();
+}
+
+void t2(){
+    T(addEdge_successors_predecessors);
+    ws::PipelineGraph g;
+    g.addEdge("a","b");
+    g.addEdge("b","c");
+    auto sb = g.successors("a");
+    C(sb.size()==1 && sb[0]=="b",   "a->b");
+    auto sc = g.successors("b");
+    C(sc.size()==1 && sc[0]=="c",   "b->c");
+    auto pb = g.predecessors("b");
+    C(pb.size()==1 && pb[0]=="a",   "b pred a");
+    C(g.predecessors("a").empty(),  "a no pred");
+    C(g.successors("c").empty(),    "c no succ");
+    P();
+}
+
+void t3(){
+    T(topologicalOrder_linear_chain);
+    ws::PipelineGraph g;
+    g.addEdge("ingest","normalize");
+    g.addEdge("normalize","fanout");
+    g.addEdge("fanout","transform");
+    g.addEdge("transform","serialize");
+    auto order = g.topologicalOrder();
+    C(order.size() == 5, "five stages in order");
+    // ingest must come before normalize, etc.
+    auto pos = [&](const std::string& s){
+        return std::find(order.begin(),order.end(),s) - order.begin();
+    };
+    C(pos("ingest")    < pos("normalize"),  "ingest before normalize");
+    C(pos("normalize") < pos("fanout"),     "normalize before fanout");
+    C(pos("fanout")    < pos("transform"),  "fanout before transform");
+    C(pos("transform") < pos("serialize"),  "transform before serialize");
+    P();
+}
+
+void t4(){
+    T(hasCycle_detection);
+    ws::PipelineGraph acyclic;
+    acyclic.addEdge("a","b");
+    acyclic.addEdge("b","c");
+    C(!acyclic.hasCycle(), "acyclic has no cycle");
+
+    ws::PipelineGraph cyclic;
+    cyclic.addEdge("a","b");
+    cyclic.addEdge("b","c");
+    cyclic.addEdge("c","a");
+    C(cyclic.hasCycle(), "cycle detected");
+    C(cyclic.topologicalOrder().empty(), "topo empty on cycle");
+    P();
+}
+
+void t5(){
+    T(sourceStages_and_sinkStages);
+    ws::PipelineGraph g;
+    g.addEdge("ingest","normalize");
+    g.addEdge("normalize","serialize");
+    auto src = g.sourceStages();
+    C(src.size()==1 && src[0]=="ingest",    "ingest is source");
+    auto sink = g.sinkStages();
+    C(sink.size()==1 && sink[0]=="serialize","serialize is sink");
+    // diamond: two sources, one sink
+    ws::PipelineGraph d;
+    d.addEdge("a","c");
+    d.addEdge("b","c");
+    C(d.sourceStages().size()==2, "diamond: two sources");
+    C(d.sinkStages().size()==1,   "diamond: one sink");
+    P();
+}
+
+int main(){
+    std::cout << "Step 1944: PipelineGraph\n";
+    t1(); t2(); t3(); t4(); t5();
+    std::cout << "\n" << p << "/" << (p+f) << " passed\n";
+    return f > 0 ? 1 : 0;
+}
diff --git a/editor/tests/step1945_test.cpp b/editor/tests/step1945_test.cpp
new file mode 100644
index 0000000..bb8cef3
--- /dev/null
+++ b/editor/tests/step1945_test.cpp
@@ -0,0 +1,107 @@
+// Step 1945: PipelineExecutionPlan
+//
+//  t1: addStage and addEdge; isValid
+//  t2: executionOrder respects topological order
+//  t3: languageSequence returns language per stage in order
+//  t4: boundaryPairs detects language transitions
+//  t5: isValid false on cycle; empty plan invalid
+
+#include "PipelineExecutionPlan.h"
+#include <algorithm>
+#include <iostream>
+
+namespace ws = whetstone;
+static int p=0,f=0;
+#define T(n) { std::cout<<"  "<<#n<<"... "; }
+#define P() { std::cout<<"PASS\n"; ++p; }
+#define F(m) { std::cout<<"FAIL: "<<m<<"\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+static ws::PipelineExecutionPlan makePipeline() {
+    ws::PipelineExecutionPlan p;
+    p.addStage({"ingest",    "Python",     "ingest",    "csv",       "records"});
+    p.addStage({"normalize", "Rust",       "normalize", "records",   "normed"});
+    p.addStage({"fanout",    "Go",         "fanout",    "normed",    "batches"});
+    p.addStage({"transform", "Haskell",    "transform", "batches",   "results"});
+    p.addStage({"serialize", "TypeScript", "serialize", "results",   "json"});
+    p.addEdge("ingest","normalize");
+    p.addEdge("normalize","fanout");
+    p.addEdge("fanout","transform");
+    p.addEdge("transform","serialize");
+    return p;
+}
+
+void t1(){
+    T(addStage_addEdge_isValid);
+    auto plan = makePipeline();
+    C(plan.isValid(), "pipeline valid");
+    P();
+}
+
+void t2(){
+    T(executionOrder_topological);
+    auto plan = makePipeline();
+    auto order = plan.executionOrder();
+    C(order.size() == 5, "five stages");
+    auto pos = [&](const std::string& id){
+        for (std::size_t i=0;i<order.size();++i)
+            if (order[i].stageId==id) return (int)i;
+        return -1;
+    };
+    C(pos("ingest")    < pos("normalize"),  "ingest before normalize");
+    C(pos("normalize") < pos("fanout"),     "normalize before fanout");
+    C(pos("fanout")    < pos("transform"),  "fanout before transform");
+    C(pos("transform") < pos("serialize"),  "transform before serialize");
+    P();
+}
+
+void t3(){
+    T(languageSequence_in_order);
+    auto plan = makePipeline();
+    auto langs = plan.languageSequence();
+    C(langs.size() == 5,         "five languages");
+    C(langs[0] == "Python",      "first Python");
+    C(langs[4] == "TypeScript",  "last TypeScript");
+    P();
+}
+
+void t4(){
+    T(boundaryPairs_language_transitions);
+    auto plan = makePipeline();
+    auto pairs = plan.boundaryPairs();
+    // Every adjacent pair differs: Python→Rust, Rust→Go, Go→Haskell, Haskell→TypeScript
+    C(pairs.size() == 4, "four boundary pairs");
+    bool hasPyRs = false;
+    for (auto& pr : pairs)
+        if (pr == "Python->Rust") hasPyRs = true;
+    C(hasPyRs, "Python->Rust boundary");
+
+    // Same-language stages produce no boundary
+    ws::PipelineExecutionPlan p2;
+    p2.addStage({"a","Go","","",""});
+    p2.addStage({"b","Go","","",""});
+    p2.addEdge("a","b");
+    C(p2.boundaryPairs().empty(), "no boundary for same language");
+    P();
+}
+
+void t5(){
+    T(isValid_cycle_and_empty);
+    ws::PipelineExecutionPlan empty;
+    C(!empty.isValid(), "empty plan invalid");
+
+    ws::PipelineExecutionPlan cyclic;
+    cyclic.addStage({"a","Python","","",""});
+    cyclic.addStage({"b","Rust","","",""});
+    cyclic.addEdge("a","b");
+    cyclic.addEdge("b","a");
+    C(!cyclic.isValid(), "cyclic plan invalid");
+    P();
+}
+
+int main(){
+    std::cout << "Step 1945: PipelineExecutionPlan\n";
+    t1(); t2(); t3(); t4(); t5();
+    std::cout << "\n" << p << "/" << (p+f) << " passed\n";
+    return f > 0 ? 1 : 0;
+}
diff --git a/editor/tests/step1946_test.cpp b/editor/tests/step1946_test.cpp
new file mode 100644
index 0000000..a3a8033
--- /dev/null
+++ b/editor/tests/step1946_test.cpp
@@ -0,0 +1,90 @@
+// Step 1946: PipelineParityValidator
+//
+//  t1: setReference and referenceCount
+//  t2: validate passes when all outputs match references
+//  t3: validate fails when output mismatches reference
+//  t4: validate fails when success=false regardless of output
+//  t5: stagePass correct; no reference set always passes
+
+#include "PipelineParityValidator.h"
+#include <iostream>
+
+namespace ws = whetstone;
+static int p=0,f=0;
+#define T(n) { std::cout<<"  "<<#n<<"... "; }
+#define P() { std::cout<<"PASS\n"; ++p; }
+#define F(m) { std::cout<<"FAIL: "<<m<<"\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+void t1(){
+    T(setReference_and_referenceCount);
+    ws::PipelineParityValidator v;
+    C(v.referenceCount() == 0, "zero initially");
+    v.setReference("ingest",    "records\n");
+    v.setReference("normalize", "normed\n");
+    C(v.referenceCount() == 2, "two references");
+    P();
+}
+
+void t2(){
+    T(validate_passes_when_all_match);
+    ws::PipelineParityValidator v;
+    v.setReference("ingest","records\n");
+    v.setReference("norm",  "normed\n");
+    std::vector<ws::StageOutput> outputs = {
+        {"ingest","Python","records\n",true},
+        {"norm",  "Rust",  "normed\n", true}
+    };
+    auto r = v.validate(outputs);
+    C(r.passed,              "passed");
+    C(r.failedStages.empty(),"no failures");
+    P();
+}
+
+void t3(){
+    T(validate_fails_on_mismatch);
+    ws::PipelineParityValidator v;
+    v.setReference("norm","normed\n");
+    std::vector<ws::StageOutput> outputs = {
+        {"norm","Rust","WRONG\n",true}
+    };
+    auto r = v.validate(outputs);
+    C(!r.passed,              "not passed");
+    C(r.failedStages.size()==1,"one failure");
+    C(r.failedStages[0]=="norm","norm failed");
+    P();
+}
+
+void t4(){
+    T(validate_fails_when_success_false);
+    ws::PipelineParityValidator v;
+    v.setReference("fanout","batches\n");
+    std::vector<ws::StageOutput> outputs = {
+        {"fanout","Go","batches\n",false}  // success=false despite matching output
+    };
+    auto r = v.validate(outputs);
+    C(!r.passed, "not passed (success=false)");
+    C(r.failedStages[0]=="fanout","fanout failed");
+    // Stage with no reference but success=false also fails
+    std::vector<ws::StageOutput> outputs2 = {{"x","Go","anything",false}};
+    auto r2 = v.validate(outputs2);
+    C(!r2.passed, "no-ref stage fails when success=false");
+    P();
+}
+
+void t5(){
+    T(stagePass_with_and_without_reference);
+    ws::PipelineParityValidator v;
+    v.setReference("norm","normed\n");
+    C( v.stagePass("norm","normed\n"),  "correct output passes");
+    C(!v.stagePass("norm","wrong\n"),   "wrong output fails");
+    C( v.stagePass("unknown","anything"),"no reference always passes");
+    P();
+}
+
+int main(){
+    std::cout << "Step 1946: PipelineParityValidator\n";
+    t1(); t2(); t3(); t4(); t5();
+    std::cout << "\n" << p << "/" << (p+f) << " passed\n";
+    return f > 0 ? 1 : 0;
+}
diff --git a/editor/tests/step1947_test.cpp b/editor/tests/step1947_test.cpp
new file mode 100644
index 0000000..c4fdcb7
--- /dev/null
+++ b/editor/tests/step1947_test.cpp
@@ -0,0 +1,116 @@
+// Step 1947: Sprint 283 Integration — poly-pipeline
+//
+//  5-stage pipeline: Python(ingest)→Rust(normalize)→Go(fanout)→Haskell(transform)→TypeScript(serialize)
+//
+//  t1: plan is valid, execution order correct, 4 boundary pairs
+//  t2: language sequence is Python Rust Go Haskell TypeScript
+//  t3: parity validation passes when all stage outputs match references
+//  t4: parity validation fails when one stage output is wrong
+//  t5: Sprint283IntegrationSummary reports 5 steps
+
+#include "PipelineExecutionPlan.h"
+#include "PipelineParityValidator.h"
+#include "Sprint283IntegrationSummary.h"
+#include <algorithm>
+#include <iostream>
+
+namespace ws = whetstone;
+static int p=0,f=0;
+#define T(n) { std::cout<<"  "<<#n<<"... "; }
+#define P() { std::cout<<"PASS\n"; ++p; }
+#define F(m) { std::cout<<"FAIL: "<<m<<"\n"; ++f; }
+#define C(c,m) if(!(c)){F(m);return;}
+
+static ws::PipelineExecutionPlan makePipeline() {
+    ws::PipelineExecutionPlan p;
+    p.addStage({"ingest",    "Python",     "CSV ingestion",       "csv",     "records"});
+    p.addStage({"normalize", "Rust",       "Data normalization",  "records", "normed"});
+    p.addStage({"fanout",    "Go",         "Fan-out routing",     "normed",  "batches"});
+    p.addStage({"transform", "Haskell",    "Statistical transform","batches", "results"});
+    p.addStage({"serialize", "TypeScript", "JSON serialization",  "results", "json"});
+    p.addEdge("ingest","normalize");
+    p.addEdge("normalize","fanout");
+    p.addEdge("fanout","transform");
+    p.addEdge("transform","serialize");
+    return p;
+}
+
+void t1(){
+    T(pipeline_valid_and_boundary_pairs);
+    auto plan = makePipeline();
+    C(plan.isValid(), "pipeline valid");
+    auto pairs = plan.boundaryPairs();
+    C(pairs.size() == 4, "four boundary pairs");
+    bool hasPyRs = std::find(pairs.begin(),pairs.end(),"Python->Rust")     != pairs.end();
+    bool hasRsGo = std::find(pairs.begin(),pairs.end(),"Rust->Go")         != pairs.end();
+    bool hasGoHs = std::find(pairs.begin(),pairs.end(),"Go->Haskell")      != pairs.end();
+    bool hasHsTs = std::find(pairs.begin(),pairs.end(),"Haskell->TypeScript") != pairs.end();
+    C(hasPyRs && hasRsGo && hasGoHs && hasHsTs, "all four language transitions");
+    P();
+}
+
+void t2(){
+    T(language_sequence_correct);
+    auto plan = makePipeline();
+    auto langs = plan.languageSequence();
+    C(langs.size() == 5,         "five languages");
+    C(langs[0] == "Python",      "Python first");
+    C(langs[1] == "Rust",        "Rust second");
+    C(langs[2] == "Go",          "Go third");
+    C(langs[3] == "Haskell",     "Haskell fourth");
+    C(langs[4] == "TypeScript",  "TypeScript fifth");
+    P();
+}
+
+void t3(){
+    T(parity_validation_all_pass);
+    ws::PipelineParityValidator v;
+    v.setReference("ingest",    "row1,row2\n");
+    v.setReference("normalize", "norm1,norm2\n");
+    v.setReference("fanout",    "batch1\n");
+    v.setReference("transform", "result1\n");
+    v.setReference("serialize", "{\"data\":1}\n");
+    std::vector<ws::StageOutput> outputs = {
+        {"ingest",    "Python",     "row1,row2\n",   true},
+        {"normalize", "Rust",       "norm1,norm2\n", true},
+        {"fanout",    "Go",         "batch1\n",      true},
+        {"transform", "Haskell",    "result1\n",     true},
+        {"serialize", "TypeScript", "{\"data\":1}\n",true}
+    };
+    auto r = v.validate(outputs);
+    C(r.passed,              "all pass");
+    C(r.failedStages.empty(),"no failures");
+    P();
+}
+
+void t4(){
+    T(parity_validation_fails_on_bad_stage);
+    ws::PipelineParityValidator v;
+    v.setReference("fanout","batch1\n");
+    v.setReference("transform","result1\n");
+    std::vector<ws::StageOutput> outputs = {
+        {"fanout",    "Go",     "WRONG\n",   true},
+        {"transform", "Haskell","result1\n", true}
+    };
+    auto r = v.validate(outputs);
+    C(!r.passed,               "not passed");
+    C(r.failedStages.size()==1,"one failure");
+    C(r.failedStages[0]=="fanout","fanout failed");
+    P();
+}
+
+void t5(){
+    T(sprint283_integration_summary);
+    ws::Sprint283IntegrationSummary s;
+    C(s.stepsCompleted == 5,                  "5 steps");
+    C(s.success,                              "success");
+    C(s.sprintName() == "Sprint 283: poly-pipeline","name");
+    P();
+}
+
+int main(){
+    std::cout << "Step 1947: Sprint 283 Integration\n";
+    t1(); t2(); t3(); t4(); t5();
+    std::cout << "\n" << p << "/" << (p+f) << " passed\n";
+    return f > 0 ? 1 : 0;
+}