fix(mcp): emit trace evidence columns in header order

json + include_evidence + data_flow labeled args as strategy because
bfs_to_tree_json declared strategy,confidence before args but emitted
args first. Tree flat_trace (risk_labels or data_flow) also dropped
include_evidence by calling bfs_to_toon_table without the flag.

Fixes DeusData#1542

Signed-off-by: rudi193-cmd <rudi193@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: rudi193-cmd

src/mcp/mcp.c

@@ -5954,25 +5954,33 @@ static bool bfs_edge_evidence_for_hop(cbm_traverse_result_t *tr, int64_t hop_nod
 }
 
 /* TOON table for one trace direction: callees[N]{qn,hop,...} with optional
- * risk / test / args columns. `name` is omitted (it is the qn's last
- * segment); the per-item JSON key envelope was 84% of the legacy payload. */
+ * risk / test / evidence / args columns. `name` is omitted (it is the qn's
+ * last segment); the per-item JSON key envelope was 84% of the legacy
+ * payload. include_evidence must be forwarded here — flat_trace used to
+ * drop it (#1542 leftover). */
 static void bfs_to_toon_table(cbm_sb_t *sb, const char *key, cbm_traverse_result_t *tr,
-                              bool risk_labels, bool include_tests, bool data_flow) {
+                              bool risk_labels, bool include_tests, bool data_flow,
+                              bool include_evidence) {
     int visible = 0;
     for (int i = 0; i < tr->visited_count; i++) {
         if (!include_tests && is_test_file(tr->visited[i].node.file_path)) {
             continue;
         }
         visible++;
     }
-    const char *cols[5] = {"qn", "hop"};
+    /* Max: qn hop risk test strategy confidence args. */
+    const char *cols[7] = {"qn", "hop"};
     int ncols = 2;
     if (risk_labels) {
         cols[ncols++] = "risk";
     }
     if (include_tests) {
         cols[ncols++] = "test";
     }
+    if (include_evidence) {
+        cols[ncols++] = "strategy";
+        cols[ncols++] = "confidence";
+    }
     if (data_flow) {
         cols[ncols++] = "args";
     }
@@ -5992,6 +6000,23 @@ static void bfs_to_toon_table(cbm_sb_t *sb, const char *key, cbm_traverse_result
         if (include_tests) {
             cbm_tree_cell_bool(sb, test, false);
         }
+        if (include_evidence) {
+            const char *ev_class = NULL;
+            double ev_conf = -1.0;
+            if (bfs_edge_evidence_for_hop(tr, tr->visited[i].node.id, &ev_class, &ev_conf)) {
+                cbm_tree_cell_str(sb, ev_class ? ev_class : "", false);
+                if (ev_conf >= 0.0) {
+                    cbm_tree_cell_real(sb, ev_conf, false);
+                } else {
+                    cbm_tree_cell_str(sb, "-", false);
+                }
+            } else {
+                /* Root hop / non-CALLS: keep column count fixed, same "-"
+                 * placeholders as bfs_to_tree_table. */
+                cbm_tree_cell_str(sb, "-", false);
+                cbm_tree_cell_str(sb, "-", false);
+            }
+        }
         if (data_flow) {
             size_t alen = 0;
             const char *ea = bfs_edge_args_for_hop(tr, tr->visited[i].node.id, &alen);
@@ -6337,20 +6362,9 @@ static yyjson_mut_val *bfs_to_tree_json(yyjson_mut_doc *doc, cbm_traverse_result
         if (risk_labels) {
             yyjson_mut_arr_add_str(doc, row, cbm_risk_label(cbm_hop_to_risk(tr->visited[i].hop)));
         }
-        if (data_flow) {
-            size_t alen = 0;
-            const char *ea = bfs_edge_args_for_hop(tr, tr->visited[i].node.id, &alen);
-            if (ea && alen > 0) {
-                yyjson_mut_val *av = yyjson_mut_rawn(doc, ea, alen);
-                if (av) {
-                    yyjson_mut_arr_add_val(row, av);
-                } else {
-                    yyjson_mut_arr_add_str(doc, row, "");
-                }
-            } else {
-                yyjson_mut_arr_add_str(doc, row, "");
-            }
-        }
+        /* Emit in header order: strategy, confidence, then args. Swapping these
+         * two blocks mislabeled every include_evidence+data_flow json row
+         * (#1542 leftover). */
         if (include_evidence) {
             const char *ev_class = NULL;
             double ev_conf = -1.0;
@@ -6370,6 +6384,20 @@ static yyjson_mut_val *bfs_to_tree_json(yyjson_mut_doc *doc, cbm_traverse_result
                 yyjson_mut_arr_add_null(doc, row);
             }
         }
+        if (data_flow) {
+            size_t alen = 0;
+            const char *ea = bfs_edge_args_for_hop(tr, tr->visited[i].node.id, &alen);
+            if (ea && alen > 0) {
+                yyjson_mut_val *av = yyjson_mut_rawn(doc, ea, alen);
+                if (av) {
+                    yyjson_mut_arr_add_val(row, av);
+                } else {
+                    yyjson_mut_arr_add_str(doc, row, "");
+                }
+            } else {
+                yyjson_mut_arr_add_str(doc, row, "");
+            }
+        }
         yyjson_mut_arr_add_val(cur_rows, row);
     }
     yyjson_mut_obj_add_val(doc, leg, "groups", groups);
@@ -6782,15 +6810,17 @@ static char *handle_trace_call_path(cbm_mcp_server_t *srv, const char *args) {
         if (do_outbound) {
             cbm_tree_scalar_int(&sb, "callees_total", out_total);
             if (flat_trace) {
-                bfs_to_toon_table(&sb, "callees", &view_out, risk_labels, include_tests, data_flow);
+                bfs_to_toon_table(&sb, "callees", &view_out, risk_labels, include_tests, data_flow,
+                                  include_evidence);
             } else {
                 bfs_to_tree_table(&sb, "callees", &view_out, include_tests, include_evidence);
             }
         }
         if (do_inbound) {
             cbm_tree_scalar_int(&sb, "callers_total", in_total);
             if (flat_trace) {
-                bfs_to_toon_table(&sb, "callers", &view_in, risk_labels, include_tests, data_flow);
+                bfs_to_toon_table(&sb, "callers", &view_in, risk_labels, include_tests, data_flow,
+                                  include_evidence);
             } else {
                 bfs_to_tree_table(&sb, "callers", &view_in, include_tests, include_evidence);
             }

tests/test_mcp.c

@@ -3385,6 +3385,118 @@ TEST(tool_trace_path_evidence_is_opt_in_and_class_mapped) {
     PASS();
 }
 
+/* #1542 leftover: header order is strategy,confidence then args, but json
+ * used to emit args first; tree flat_trace (risk_labels || data_flow) used
+ * to call bfs_to_toon_table without include_evidence. Pin both: every row
+ * has len(cols)==len(row), and the strategy cell is the class not the args
+ * array. */
+TEST(tool_trace_path_evidence_columns_match_header_issue1542) {
+    cbm_mcp_server_t *srv = cbm_mcp_server_new(NULL);
+    cbm_store_t *st = cbm_mcp_server_store(srv);
+    const char *proj = "ev-order";
+    cbm_mcp_server_set_project(srv, proj);
+    cbm_store_upsert_project(st, proj, "/tmp/ev-order");
+    cbm_node_t caller = {.project = proj,
+                         .label = "Function",
+                         .name = "caller",
+                         .qualified_name = "ev-order.src.caller",
+                         .file_path = "src/a.c",
+                         .start_line = 1,
+                         .end_line = 5};
+    cbm_node_t callee = {.project = proj,
+                         .label = "Function",
+                         .name = "target",
+                         .qualified_name = "ev-order.src.target",
+                         .file_path = "src/a.c",
+                         .start_line = 10,
+                         .end_line = 20};
+    int64_t id_caller = cbm_store_upsert_node(st, &caller);
+    int64_t id_callee = cbm_store_upsert_node(st, &callee);
+    ASSERT_GT(id_caller, 0);
+    ASSERT_GT(id_callee, 0);
+    cbm_edge_t e = {.project = proj,
+                    .source_id = id_caller,
+                    .target_id = id_callee,
+                    .type = "CALLS",
+                    .properties_json = "{\"callee\":\"target\",\"confidence\":0.95,"
+                                       "\"strategy\":\"lsp_trait_dispatch\",\"candidates\":1,"
+                                       "\"args\":[\"x\"]}"};
+    ASSERT_GT(cbm_store_insert_edge(st, &e), 0);
+
+    /* json × data_flow × include_evidence: cols identity, not just count. */
+    char *js = cbm_mcp_server_handle(
+        srv, "{\"jsonrpc\":\"2.0\",\"id\":94,\"method\":\"tools/call\","
+             "\"params\":{\"name\":\"trace_path\",\"arguments\":{\"function_name\":\"caller\","
+             "\"project\":\"ev-order\",\"direction\":\"outbound\",\"include_evidence\":true,"
+             "\"mode\":\"data_flow\",\"format\":\"json\"}}}");
+    ASSERT_NOT_NULL(js);
+    char *js_txt = extract_text_content(js);
+    ASSERT_NOT_NULL(js_txt);
+    yyjson_doc *doc = yyjson_read(js_txt, strlen(js_txt), 0);
+    ASSERT_NOT_NULL(doc);
+    yyjson_val *callees = yyjson_obj_get(yyjson_doc_get_root(doc), "callees");
+    ASSERT_NOT_NULL(callees);
+    yyjson_val *cols = yyjson_obj_get(callees, "cols");
+    ASSERT_NOT_NULL(cols);
+    static const char *want[] = {"name", "hop", "strategy", "confidence", "args"};
+    ASSERT_EQ((int)yyjson_arr_size(cols), 5);
+    for (int i = 0; i < 5; i++) {
+        ASSERT_STR_EQ(yyjson_get_str(yyjson_arr_get(cols, i)), want[i]);
+    }
+    yyjson_val *hop1 = NULL;
+    yyjson_val *groups = yyjson_obj_get(callees, "groups");
+    ASSERT_NOT_NULL(groups);
+    size_t ng = yyjson_arr_size(groups);
+    for (size_t g = 0; g < ng; g++) {
+        yyjson_val *rows = yyjson_obj_get(yyjson_arr_get(groups, g), "rows");
+        if (!rows) {
+            continue;
+        }
+        size_t nr = yyjson_arr_size(rows);
+        for (size_t r = 0; r < nr; r++) {
+            yyjson_val *row = yyjson_arr_get(rows, r);
+            yyjson_val *hop = row ? yyjson_arr_get(row, 1) : NULL;
+            if (hop && yyjson_get_int(hop) >= 1) {
+                hop1 = row;
+                break;
+            }
+        }
+        if (hop1) {
+            break;
+        }
+    }
+    ASSERT_NOT_NULL(hop1);
+    ASSERT_EQ((int)yyjson_arr_size(hop1), 5);
+    ASSERT_TRUE(yyjson_is_str(yyjson_arr_get(hop1, 2)));
+    ASSERT_STR_EQ(yyjson_get_str(yyjson_arr_get(hop1, 2)), "lsp");
+    ASSERT_TRUE(yyjson_is_num(yyjson_arr_get(hop1, 3)));
+    ASSERT_TRUE(yyjson_is_arr(yyjson_arr_get(hop1, 4)));
+    yyjson_doc_free(doc);
+    free(js_txt);
+    free(js);
+
+    /* tree × risk_labels × include_evidence used to drop evidence entirely
+     * because flat_trace routed through bfs_to_toon_table without the flag. */
+    char *tree = cbm_mcp_server_handle(
+        srv, "{\"jsonrpc\":\"2.0\",\"id\":95,\"method\":\"tools/call\","
+             "\"params\":{\"name\":\"trace_path\",\"arguments\":{\"function_name\":\"caller\","
+             "\"project\":\"ev-order\",\"direction\":\"outbound\",\"include_evidence\":true,"
+             "\"risk_labels\":true}}}");
+    ASSERT_NOT_NULL(tree);
+    char *tree_txt = extract_text_content(tree);
+    ASSERT_NOT_NULL(tree_txt);
+    ASSERT_NOT_NULL(strstr(tree_txt, "strategy"));
+    ASSERT_NOT_NULL(strstr(tree_txt, "confidence"));
+    ASSERT_NOT_NULL(strstr(tree_txt, "lsp"));
+    ASSERT_NOT_NULL(strstr(tree_txt, "0.95"));
+    ASSERT_NULL(strstr(tree_txt, "lsp_trait_dispatch"));
+    free(tree_txt);
+    free(tree);
+
+    cbm_mcp_server_free(srv);
+    PASS();
+}
+
 /* Reproduce-first (#887): the client-supplied `depth` on trace_call_path must be
  * clamped to the MCP ceiling (cbm_mcp_max_depth(), default 15). On origin/main
  * an MCP_MAX_DEPTH=15 constant was defined but never applied — `depth` flowed
@@ -11188,6 +11300,7 @@ SUITE(mcp) {
     RUN_TEST(tool_trace_call_path_prefers_definition);
     RUN_TEST(trace_evidence_strategy_class_vocabulary_is_closed);
     RUN_TEST(tool_trace_path_evidence_is_opt_in_and_class_mapped);
+    RUN_TEST(tool_trace_path_evidence_columns_match_header_issue1542);
     RUN_TEST(tool_trace_call_path_depth_clamped);
     RUN_TEST(tool_trace_call_path_distinct_defs_not_over_unioned);
     RUN_TEST(tool_trace_call_path_dts_stub_unions_with_impl);