Wire blast radius public surface

Add the impact-analysis store API declaration, expose get_impact_analysis in CLI help text, and cover the tool with the existing integration fixture.

Author: Naman Khator

src/main.c

@@ -150,7 +150,7 @@ static void print_help(void) {
     printf("  Claude Code, Codex CLI, Gemini CLI, Zed, OpenCode, Antigravity, Aider, KiloCode\n");
     printf("\nTools: index_repository, search_graph, query_graph, trace_call_path,\n");
     printf("  get_code_snippet, get_graph_schema, get_architecture,\n");
-    printf("  get_architecture_summary, search_code,\n");
+    printf("  get_architecture_summary, get_impact_analysis, search_code,\n");
     printf("  get_key_symbols,\n");
     printf("  list_projects, delete_project, index_status, detect_changes,\n");
     printf("  manage_adr, ingest_traces\n");

src/store/store.h

@@ -429,6 +429,40 @@ cbm_impact_summary_t cbm_build_impact_summary(const cbm_node_hop_t *hops, int ho
 int cbm_deduplicate_hops(const cbm_node_hop_t *hops, int hop_count, cbm_node_hop_t **out,
                          int *out_count);
 
+typedef struct {
+    const char *name;
+    const char *file;
+    const char *type;
+    double pagerank;
+    int hop; /* internal traversal depth used for ordering/grouping */
+} cbm_impact_item_t;
+
+typedef struct {
+    const char *name;
+    const char *file;
+} cbm_affected_test_t;
+
+typedef struct {
+    const char *symbol;
+    const char *qualified_name;
+    const char *file;
+    double pagerank;
+    cbm_impact_item_t *direct;
+    int direct_count;
+    cbm_impact_item_t *indirect;
+    int indirect_count;
+    cbm_impact_item_t *transitive;
+    int transitive_count;
+    cbm_affected_test_t *affected_tests;
+    int affected_test_count;
+    const char *risk_score;
+    const char *summary;
+} cbm_impact_analysis_t;
+
+int cbm_store_get_impact_analysis(cbm_store_t *s, const char *project, const char *symbol,
+                                  int depth, cbm_impact_analysis_t *out);
+void cbm_store_impact_analysis_free(cbm_impact_analysis_t *out);
+
 /* ── Schema ─────────────────────────────────────────────────────── */
 
 int cbm_store_get_schema(cbm_store_t *s, const char *project, cbm_schema_info_t *out);

tests/test_integration.c

@@ -393,6 +393,20 @@ TEST(integ_mcp_get_key_symbols) {
     PASS();
 }
 
+TEST(integ_mcp_get_impact_analysis) {
+    char args[256];
+    snprintf(args, sizeof(args), "{\"project\":\"%s\",\"symbol\":\"Add\",\"depth\":3}", g_project);
+
+    char *resp = call_tool("get_impact_analysis", args);
+    ASSERT_NOT_NULL(resp);
+    ASSERT_NOT_NULL(strstr(resp, "\"symbol\":\"Add\""));
+    ASSERT_NOT_NULL(strstr(resp, "\"impact\""));
+    ASSERT_NOT_NULL(strstr(resp, "\"risk_score\""));
+    ASSERT_TRUE(strstr(resp, "Multiply") || strstr(resp, "Compute"));
+    free(resp);
+    PASS();
+}
+
 TEST(integ_mcp_trace_call_path) {
     /* Trace outbound calls from Compute → should reach Add and Multiply */
     char args[256];
@@ -575,7 +589,7 @@ SUITE(integration) {
     if (integration_setup() != 0) {
         printf("  %-50s", "integration_setup");
         printf("SKIP (setup failed)\n");
-        tf_skip_count += 25; /* skip all integration tests */
+        tf_skip_count += 26; /* skip all integration tests */
         integration_teardown();
         return;
     }
@@ -597,6 +611,7 @@ SUITE(integration) {
     RUN_TEST(integ_mcp_get_architecture);
     RUN_TEST(integ_mcp_get_architecture_summary);
     RUN_TEST(integ_mcp_get_key_symbols);
+    RUN_TEST(integ_mcp_get_impact_analysis);
     RUN_TEST(integ_mcp_trace_call_path);
     RUN_TEST(integ_mcp_index_status);