mcp: fix 6 bugs + token optimization + empty DB reindex + 4 TDD tests

Bugs fixed: - _hidden_tools dispatch: returns tool list instead of "unknown tool" error - trace_call_path: accepts project paths via expand_project_param (DRY resolve_project_store helper shared with search_code_graph) - Resources scoping: codebase://schema/architecture/status now reflect the most-recently-queried project (active_project_name) instead of always returning the empty session CWD project - compact default: search/trace default to compact=true via new cbm_mcp_get_bool_arg_default() — omits redundant name field - PageRank precision: add_pagerank_val() writes raw JSON via %.4g format (e.g. 4.755e-05) instead of 17-digit doubles, no float round-trip - Empty DB skip: maybe_auto_index now checks db_has_content() (SELECT 1 FROM nodes LIMIT 1) instead of just stat(). Empty DBs trigger reindex. New features: - db_is_stale(): compares DB mtime vs git HEAD commit time, with configurable max_age_seconds (reindex_stale_seconds config key) - reindex_on_startup config: when true + stale DB, triggers reindex at server start. Default false for large project safety. DRY refactors: - resolve_project_store(): extracted from handle_search_graph, reused by handle_trace_call_path. Handles expand_project_param + DB selection + prefix collision avoidance + auto-index on first use. Tests (2193 → 2197): - hidden_tools_returns_info_not_error - compact_defaults_to_true - pagerank_output_has_limited_precision - empty_db_not_treated_as_indexed Signed-off-by: Andrew Hundt <ATHundt@gmail.com>
2026-11-08 08:53:43 +08:00 · 2026-03-23 05:49:38 -04:00
parent 47bbe5cd51
commit 719cdfe57f
3 changed files with 322 additions and 35 deletions
@@ -41,6 +41,16 @@

 /* ── Constants ────────────────────────────────────────────────── */

+/* Add a "pagerank" key with value formatted to 4 significant figures.
+ * Writes directly as a raw JSON number (e.g. 4.755e-05) — no double round-trip.
+ * 4 sig figs preserves ranking distinguishability while saving ~12 chars/value.
+ * This is the single place pagerank values are serialized to JSON. */
+static void add_pagerank_val(yyjson_mut_doc *doc, yyjson_mut_val *obj, double v) {
+    char buf[32];
+    snprintf(buf, sizeof(buf), "%.4g", v);
+    yyjson_mut_obj_add_val(doc, obj, "pagerank", yyjson_mut_rawcpy(doc, buf));
+}
+
 /* Default snippet fallback line count (when end_line unknown) */
 #define SNIPPET_DEFAULT_LINES 50

@@ -281,7 +291,7 @@ static const tool_def_t TOOLS[] = {
     "\"mode\":{\"type\":\"string\",\"enum\":[\"full\",\"summary\"],\"default\":\"full\","
     "\"description\":\"full=individual results (default), summary=aggregate counts by label and "
     "file. Use summary first to understand scope, then full with filters to drill down."
-     "\"},\"compact\":{\"type\":\"boolean\",\"default\":false,\"description\":\"Omit redundant "
+     "\"},\"compact\":{\"type\":\"boolean\",\"default\":true,\"description\":\"Omit redundant "
     "name field when it matches the last segment of qualified_name. Reduces token usage.\"},"
     "\"include_dependencies\":{\"type\":\"boolean\",\"default\":false,\"description\":\"Include "
     "indexed dependency symbols in results. Results from dependencies have source:dependency. "
@@ -586,13 +596,17 @@ int cbm_mcp_get_int_arg(const char *args_json, const char *key, int default_val)

 // NOLINTNEXTLINE(bugprone-easily-swappable-parameters)
 bool cbm_mcp_get_bool_arg(const char *args_json, const char *key) {
+    return cbm_mcp_get_bool_arg_default(args_json, key, false);
+}
+
+bool cbm_mcp_get_bool_arg_default(const char *args_json, const char *key, bool default_val) {
    yyjson_doc *doc = yyjson_read(args_json, strlen(args_json), 0);
    if (!doc) {
-        return false;
+        return default_val;
    }
    yyjson_val *root = yyjson_doc_get_root(doc);
    yyjson_val *val = yyjson_obj_get(root, key);
-    bool result = false;
+    bool result = default_val;
    if (val && yyjson_is_bool(val)) {
        result = yyjson_get_bool(val);
    }
@@ -1388,15 +1402,21 @@ static char *handle_get_graph_schema(cbm_mcp_server_t *srv, const char *args) {
    return result;
 }

-static char *handle_search_graph(cbm_mcp_server_t *srv, const char *args) {
-    char *raw_project = cbm_mcp_get_string_arg(args, "project");
+/* Expand a raw project param, resolve the correct store, and auto-index if needed.
+ * Returns the resolved store (or NULL). Sets *out_pe to the expand result
+ * (caller must free out_pe->value). Handles:
+ *   - expand_project_param (Rule 0: /path → project name)
+ *   - DB selection with prefix collision avoidance
+ *   - Auto-index on first use (join background thread or sync index) */
+static cbm_store_t *resolve_project_store(cbm_mcp_server_t *srv,
+                                           char *raw_project,
+                                           project_expand_t *out_pe) {
    project_expand_t pe = expand_project_param(srv, raw_project);

    /* DB selection: if expanded value IS the session project or a dep of it
-     * (session.dep.X), use session store. Otherwise open the requested project's DB.
-     * The check requires the char after session_project to be '.' or '\0' to avoid
-     * prefix collisions (e.g., "myapp" matching "myapp-other-project"). */
-    const char *db_project = pe.value; /* default: pass through to resolve_store */
+     * (session.dep.X), use session store. The check requires the char after
+     * session_project to be '.' or '\0' to avoid prefix collisions. */
+    const char *db_project = pe.value;
    if (pe.value && srv->session_project[0]) {
        size_t sp_len = strlen(srv->session_project);
        if (strncmp(pe.value, srv->session_project, sp_len) == 0 &&
@@ -1405,8 +1425,8 @@ static char *handle_search_graph(cbm_mcp_server_t *srv, const char *args) {
        }
    }
    cbm_store_t *store = resolve_store(srv, db_project);
-    /* Auto-index on first use — same logic as REQUIRE_STORE macro.
-     * Handles: CWD-based session_root, explicit path via Rule 0, MCP roots. */
+
+    /* Auto-index on first use (same logic as REQUIRE_STORE macro). */
    if (!store && srv->session_root[0] && access(srv->session_root, F_OK) == 0) {
        if (srv->autoindex_active) {
            cbm_thread_join(&srv->autoindex_tid);
@@ -1433,6 +1453,15 @@ static char *handle_search_graph(cbm_mcp_server_t *srv, const char *args) {
            }
        }
    }
+
+    *out_pe = pe; /* caller takes ownership of pe.value */
+    return store;
+}
+
+static char *handle_search_graph(cbm_mcp_server_t *srv, const char *args) {
+    char *raw_project = cbm_mcp_get_string_arg(args, "project");
+    project_expand_t pe = {0};
+    cbm_store_t *store = resolve_project_store(srv, raw_project, &pe);
    if (!store) {
        free(pe.value);
        return cbm_mcp_text_result(
@@ -1448,7 +1477,7 @@ static char *handle_search_graph(cbm_mcp_server_t *srv, const char *args) {
                                               CBM_DEFAULT_SEARCH_LIMIT);
    int limit = cbm_mcp_get_int_arg(args, "limit", cfg_search_limit);
    int offset = cbm_mcp_get_int_arg(args, "offset", 0);
-    bool compact = cbm_mcp_get_bool_arg(args, "compact");
+    bool compact = cbm_mcp_get_bool_arg_default(args, "compact", true);
    char *search_mode = cbm_mcp_get_string_arg(args, "mode");
    int min_degree = cbm_mcp_get_int_arg(args, "min_degree", -1);
    int max_degree = cbm_mcp_get_int_arg(args, "max_degree", -1);
@@ -1547,7 +1576,7 @@ static char *handle_search_graph(cbm_mcp_server_t *srv, const char *args) {
            yyjson_mut_obj_add_str(doc, item, "file_path",
                                   sr->node.file_path ? sr->node.file_path : "");
            if (sr->pagerank_score > 0.0) {
-                yyjson_mut_obj_add_real(doc, item, "pagerank", sr->pagerank_score);
+                add_pagerank_val(doc, item, sr->pagerank_score);
            } else {
                /* Degree fields only when PageRank not available — PR subsumes degree info */
                yyjson_mut_obj_add_int(doc, item, "in_degree", sr->in_degree);
@@ -1919,7 +1948,7 @@ static char *handle_get_architecture(cbm_mcp_server_t *srv, const char *args) {
                    if (qn) yyjson_mut_obj_add_strcpy(doc, kf, "qualified_name", qn);
                    if (lbl) yyjson_mut_obj_add_strcpy(doc, kf, "label", lbl);
                    if (fp) yyjson_mut_obj_add_strcpy(doc, kf, "file_path", fp);
-                    yyjson_mut_obj_add_real(doc, kf, "pagerank", rank);
+                    add_pagerank_val(doc, kf, rank);
                    yyjson_mut_arr_add_val(kf_arr, kf);
                }
                sqlite3_finalize(kf_stmt);
@@ -1940,14 +1969,16 @@ static char *handle_get_architecture(cbm_mcp_server_t *srv, const char *args) {

 static char *handle_trace_call_path(cbm_mcp_server_t *srv, const char *args) {
    char *func_name = cbm_mcp_get_string_arg(args, "function_name");
-    char *project = cbm_mcp_get_string_arg(args, "project");
-    cbm_store_t *store = resolve_store(srv, project);
+    char *raw_project = cbm_mcp_get_string_arg(args, "project");
+    project_expand_t pe = {0};
+    cbm_store_t *store = resolve_project_store(srv, raw_project, &pe);
+    char *project = pe.value; /* take ownership for free() below */
    char *direction = cbm_mcp_get_string_arg(args, "direction");
    int depth = cbm_mcp_get_int_arg(args, "depth", 3);
    int cfg_trace_max = cbm_config_get_int(srv->config, CBM_CONFIG_TRACE_MAX_RESULTS,
                                            CBM_DEFAULT_TRACE_MAX_RESULTS);
    int max_results = cbm_mcp_get_int_arg(args, "max_results", cfg_trace_max);
-    bool compact = cbm_mcp_get_bool_arg(args, "compact");
+    bool compact = cbm_mcp_get_bool_arg_default(args, "compact", true);

    if (!func_name) {
        free(project);
@@ -2052,7 +2083,7 @@ static char *handle_trace_call_path(cbm_mcp_server_t *srv, const char *args) {
            {
                double pr = cbm_pagerank_get(store, tr_out.visited[i].node.id);
                if (pr > 0.0)
-                    yyjson_mut_obj_add_real(doc, item, "pagerank", pr);
+                    add_pagerank_val(doc, item, pr);
            }
            /* Boundary tagging: mark if callee is in a dependency */
            bool callee_dep = cbm_is_dep_project(tr_out.visited[i].node.project,
@@ -2099,7 +2130,7 @@ static char *handle_trace_call_path(cbm_mcp_server_t *srv, const char *args) {
            {
                double pr = cbm_pagerank_get(store, tr_in.visited[i].node.id);
                if (pr > 0.0)
-                    yyjson_mut_obj_add_real(doc, item, "pagerank", pr);
+                    add_pagerank_val(doc, item, pr);
            }
            /* Boundary tagging: mark if caller is in a dependency */
            bool caller_dep = cbm_is_dep_project(tr_in.visited[i].node.project,
@@ -3435,6 +3466,18 @@ char *cbm_mcp_handle_tool(cbm_mcp_server_t *srv, const char *tool_name, const ch
        return handle_index_dependencies(srv, args_json);
    }

+    /* _hidden_tools: informational pseudo-tool for progressive disclosure */
+    if (strcmp(tool_name, "_hidden_tools") == 0) {
+        return cbm_mcp_text_result(
+            "{\"hidden_tools\":[\"index_repository\",\"search_graph\",\"query_graph\","
+            "\"get_code_snippet\",\"get_graph_schema\",\"get_architecture\",\"search_code\","
+            "\"list_projects\",\"delete_project\",\"index_status\",\"detect_changes\","
+            "\"manage_adr\",\"ingest_traces\",\"index_dependencies\"],"
+            "\"enable_all\":\"set env CBM_TOOL_MODE=classic or config set tool_mode classic\","
+            "\"enable_one\":\"config set tool_<name> true (e.g. tool_index_repository true)\","
+            "\"resources\":[\"codebase://schema\",\"codebase://architecture\",\"codebase://status\"]}", false);
+    }
+
    char msg[512];
    snprintf(msg, sizeof(msg),
        "{\"error\":\"unknown tool: '%s'\","
@@ -3522,31 +3565,122 @@ static void *autoindex_thread(void *arg) {
    return NULL;
 }

+/* Check if a DB file has actual content (at least 1 node).
+ * Returns true if DB exists AND has nodes. Lightweight raw SQLite check. */
+static bool db_has_content(const char *db_path) {
+    struct stat st;
+    if (stat(db_path, &st) != 0) return false; /* file doesn't exist */
+
+    sqlite3 *db = NULL;
+    if (sqlite3_open_v2(db_path, &db, SQLITE_OPEN_READONLY, NULL) != SQLITE_OK) {
+        sqlite3_close(db);
+        return false;
+    }
+    sqlite3_stmt *stmt = NULL;
+    bool has = false;
+    if (sqlite3_prepare_v2(db, "SELECT 1 FROM nodes LIMIT 1", -1, &stmt, NULL) == SQLITE_OK) {
+        has = (sqlite3_step(stmt) == SQLITE_ROW);
+        sqlite3_finalize(stmt);
+    }
+    sqlite3_close(db);
+    return has;
+}
+
+/* Check if a DB's index is stale by comparing DB file mtime against latest
+ * git commit time. If the repo has commits newer than the DB, it's stale.
+ * Also stale if DB is older than max_age_seconds (0 = disabled).
+ * Returns false on any error (conservative: don't trigger unnecessary reindex). */
+static bool db_is_stale(const char *db_path, const char *repo_path, int max_age_seconds) {
+    struct stat db_st;
+    if (stat(db_path, &db_st) != 0) return false;
+    time_t db_mtime = db_st.st_mtime;
+
+    /* Check age-based staleness (configurable, 0 = disabled).
+     * Guard against clock skew: only consider stale if now > db_mtime. */
+    if (max_age_seconds > 0) {
+        time_t now = time(NULL);
+        if (now > db_mtime && (now - db_mtime) > max_age_seconds) return true;
+    }
+
+    /* Check git HEAD commit time vs DB mtime */
+    char cmd[1024];
+    snprintf(cmd, sizeof(cmd),
+        "git -C '%s' log -1 --format=%%ct HEAD 2>/dev/null", repo_path);
+    // NOLINTNEXTLINE(bugprone-command-processor,cert-env33-c)
+    FILE *fp = cbm_popen(cmd, "r");
+    if (!fp) return false;
+    char line[64] = {0};
+    if (fgets(line, sizeof(line), fp)) {
+        long commit_time = strtol(line, NULL, 10);
+        cbm_pclose(fp);
+        /* Stale if latest commit is newer than DB */
+        return commit_time > (long)db_mtime;
+    }
+    cbm_pclose(fp);
+    return false;
+}
+
+/* Config keys for reindex behavior */
+#define CBM_CONFIG_REINDEX_ON_STARTUP "reindex_on_startup"
+#define CBM_CONFIG_REINDEX_STALE_SECONDS "reindex_stale_seconds"
+
 /* Start auto-indexing if configured and project not yet indexed. */
 static void maybe_auto_index(cbm_mcp_server_t *srv) {
    if (srv->session_root[0] == '\0') {
        return; /* no session root detected */
    }

-    /* Check if project already has a DB */
+    /* Check if project already has a populated DB */
    // NOLINTNEXTLINE(concurrency-mt-unsafe)
    const char *home = getenv("HOME");
+    bool needs_index = true;
+    char db_check[1024] = {0};
    if (home) {
-        char db_check[1024];
        snprintf(db_check, sizeof(db_check), "%s/.cache/codebase-memory-mcp/%s.db", home,
                 srv->session_project);
-        struct stat st;
-        if (stat(db_check, &st) == 0) {
-            /* Already indexed → register watcher for change detection */
-            cbm_log_info("autoindex.skip", "reason", "already_indexed", "project",
-                         srv->session_project);
-            if (srv->watcher) {
-                cbm_watcher_watch(srv->watcher, srv->session_project, srv->session_root);
+
+        if (db_has_content(db_check)) {
+            /* DB exists and has nodes — check if stale */
+            bool reindex_on_startup = srv->config
+                ? cbm_config_get_bool(srv->config, CBM_CONFIG_REINDEX_ON_STARTUP, false)
+                : false;
+            int stale_seconds = srv->config
+                ? cbm_config_get_int(srv->config, CBM_CONFIG_REINDEX_STALE_SECONDS, 0)
+                : 0;
+            bool stale = db_is_stale(db_check, srv->session_root, stale_seconds);
+
+            if (stale && reindex_on_startup) {
+                cbm_log_info("autoindex.stale", "reason", "commits_newer_than_index", "project",
+                             srv->session_project);
+                needs_index = true;
+            } else {
+                if (stale) {
+                    cbm_log_info("autoindex.stale_skipped", "reason", "reindex_on_startup=false",
+                                 "hint", "set reindex_on_startup true to auto-update on restart",
+                                 "project", srv->session_project);
+                } else {
+                    cbm_log_info("autoindex.skip", "reason", "already_indexed", "project",
+                                 srv->session_project);
+                }
+                /* Register watcher for live change detection */
+                if (srv->watcher) {
+                    cbm_watcher_watch(srv->watcher, srv->session_project, srv->session_root);
+                }
+                needs_index = false;
            }
-            return;
+        } else {
+            struct stat st;
+            if (stat(db_check, &st) == 0) {
+                /* DB file exists but has 0 nodes — treat as not indexed */
+                cbm_log_info("autoindex.empty_db", "reason", "db_exists_but_empty", "project",
+                             srv->session_project);
+            }
+            needs_index = true;
        }
    }

+    if (!needs_index) return;
+
 /* Default file limit for auto-indexing new projects */
 #define DEFAULT_AUTO_INDEX_LIMIT 50000

@@ -3775,9 +3909,20 @@ static char *handle_resources_list(cbm_mcp_server_t *srv) {
    return out;
 }

-/* Resolve session store for resource handlers. Opens the session project DB
- * if not already open, so resources return data even before any tool call. */
+/* Get the active project name: current_project (from last tool call) or session_project. */
+static const char *active_project_name(cbm_mcp_server_t *srv) {
+    if (srv->current_project) return srv->current_project;
+    return srv->session_project[0] ? srv->session_project : NULL;
+}
+
+/* Resolve store for resource handlers. Prefers the currently-open project
+ * (set by the most recent tool call) over the session project, so resources
+ * reflect data the user is actually querying — not the empty CWD project. */
 static cbm_store_t *resolve_resource_store(cbm_mcp_server_t *srv) {
+    /* 1. Use currently-open project (set by last resolve_store call) */
+    if (srv->current_project && srv->store)
+        return srv->store;
+    /* 2. Fall back to session project */
    const char *proj = srv->session_project[0] ? srv->session_project : NULL;
    if (proj) return resolve_store(srv, proj);
    return srv->store;
@@ -3787,7 +3932,7 @@ static cbm_store_t *resolve_resource_store(cbm_mcp_server_t *srv) {
 static void build_resource_schema(yyjson_mut_doc *doc, yyjson_mut_val *root,
                                  cbm_mcp_server_t *srv) {
    cbm_store_t *store = resolve_resource_store(srv);
-    const char *proj = srv->session_project[0] ? srv->session_project : NULL;
+    const char *proj = active_project_name(srv);

    if (!store) {
        yyjson_mut_obj_add_str(doc, root, "status", "not_indexed");
@@ -3821,7 +3966,7 @@ static void build_resource_schema(yyjson_mut_doc *doc, yyjson_mut_val *root,
 static void build_resource_architecture(yyjson_mut_doc *doc, yyjson_mut_val *root,
                                        cbm_mcp_server_t *srv) {
    cbm_store_t *store = resolve_resource_store(srv);
-    const char *proj = srv->session_project[0] ? srv->session_project : NULL;
+    const char *proj = active_project_name(srv);

    if (!store) {
        yyjson_mut_obj_add_str(doc, root, "status", "not_indexed");
@@ -3855,7 +4000,7 @@ static void build_resource_architecture(yyjson_mut_doc *doc, yyjson_mut_val *roo
                if (qn) yyjson_mut_obj_add_strcpy(doc, kf, "qualified_name", qn);
                if (label) yyjson_mut_obj_add_strcpy(doc, kf, "label", label);
                if (fp) yyjson_mut_obj_add_strcpy(doc, kf, "file_path", fp);
-                yyjson_mut_obj_add_real(doc, kf, "pagerank", rank);
+                add_pagerank_val(doc, kf, rank);
                yyjson_mut_arr_add_val(kf_arr, kf);
            }
            yyjson_mut_obj_add_val(doc, root, "key_functions", kf_arr);
@@ -3880,7 +4025,7 @@ static void build_resource_architecture(yyjson_mut_doc *doc, yyjson_mut_val *roo
 static void build_resource_status(yyjson_mut_doc *doc, yyjson_mut_val *root,
                                  cbm_mcp_server_t *srv) {
    cbm_store_t *store = resolve_resource_store(srv);
-    const char *proj = srv->session_project[0] ? srv->session_project : NULL;
+    const char *proj = active_project_name(srv);

    if (proj) yyjson_mut_obj_add_str(doc, root, "project", proj);

@@ -72,6 +72,9 @@ int cbm_mcp_get_int_arg(const char *args_json, const char *key, int default_val)
 /* Extract a bool argument. Returns false if not found. */
 bool cbm_mcp_get_bool_arg(const char *args_json, const char *key);

+/* Extract a bool argument with explicit default. Returns default_val if key absent. */
+bool cbm_mcp_get_bool_arg_default(const char *args_json, const char *key, bool default_val);
+
 /* Extract the tool name from a tools/call params JSON. Heap-allocated. */
 char *cbm_mcp_get_tool_name(const char *params_json);

@@ -13,6 +13,10 @@
 #include <string.h>
 #include <stdlib.h>
 #include <watcher/watcher.h>
+#include <pagerank/pagerank.h>
+#include <sqlite3.h>
+#include <sys/stat.h>
+#include <unistd.h>

 /* ── 1. Tool visibility tests ─────────────────────────────── */

@@ -1410,6 +1414,136 @@ TEST(watcher_not_registered_for_unknown_path) {
    PASS();
 }

+/* ── Empty DB / stale index detection ────────────────────── */
+
+TEST(hidden_tools_returns_info_not_error) {
+    /* _hidden_tools should return tool list, not "unknown tool" error */
+    cbm_mcp_server_t *srv = cbm_mcp_server_new(NULL);
+    ASSERT_NOT_NULL(srv);
+    char *resp = cbm_mcp_handle_tool(srv, "_hidden_tools", "{}");
+    ASSERT_NOT_NULL(resp);
+    ASSERT_NOT_NULL(strstr(resp, "hidden_tools"));
+    ASSERT_NOT_NULL(strstr(resp, "index_repository"));
+    /* Must NOT be an error */
+    ASSERT_NULL(strstr(resp, "unknown tool"));
+    free(resp);
+    cbm_mcp_server_free(srv);
+    PASS();
+}
+
+TEST(compact_defaults_to_true) {
+    /* When compact is not provided, name field should be omitted if it's
+     * the last segment of qualified_name */
+    char db_path[1024];
+    snprintf(db_path, sizeof(db_path), "%s/.cache/codebase-memory-mcp/_tc_compact_default_.db",
+             getenv("HOME"));
+    cbm_store_t *s = cbm_store_open_path(db_path);
+    ASSERT_NOT_NULL(s);
+    cbm_store_upsert_project(s, "_tc_compact_default_", "/tmp/compact_test");
+    cbm_node_t n = {.project = "_tc_compact_default_", .label = "Function",
+                    .name = "my_func", .qualified_name = "_tc_compact_default_.my_func",
+                    .file_path = "test.c"};
+    cbm_store_upsert_node(s, &n);
+    cbm_store_close(s);
+
+    cbm_mcp_server_t *srv = cbm_mcp_server_new(NULL);
+    ASSERT_NOT_NULL(srv);
+    /* Search WITHOUT compact param — should default to compact=true */
+    char *resp = cbm_mcp_handle_tool(srv, "search_code_graph",
+        "{\"project\":\"_tc_compact_default_\",\"name_pattern\":\"my_func\",\"limit\":1}");
+    ASSERT_NOT_NULL(resp);
+    /* In compact mode, "name" should NOT appear as a separate key when
+     * it matches the last segment of qualified_name */
+    /* Parse the result text to check */
+    yyjson_doc *doc = yyjson_read(resp, strlen(resp), 0);
+    ASSERT_NOT_NULL(doc);
+    yyjson_val *root = yyjson_doc_get_root(doc);
+    yyjson_val *results = yyjson_obj_get(root, "results");
+    if (results && yyjson_arr_size(results) > 0) {
+        yyjson_val *first = yyjson_arr_get_first(results);
+        /* name key should be absent in compact mode */
+        ASSERT_NULL(yyjson_obj_get(first, "name"));
+        ASSERT_NOT_NULL(yyjson_obj_get(first, "qualified_name"));
+    }
+    yyjson_doc_free(doc);
+    free(resp);
+    cbm_mcp_server_free(srv);
+    (void)unlink(db_path);
+    PASS();
+}
+
+TEST(pagerank_output_has_limited_precision) {
+    /* Pagerank values should be serialized with limited precision (~4 sig figs),
+     * not full 17-digit double precision */
+    char db_path[1024];
+    snprintf(db_path, sizeof(db_path), "%s/.cache/codebase-memory-mcp/_tc_pr_precision_.db",
+             getenv("HOME"));
+    cbm_store_t *s = cbm_store_open_path(db_path);
+    ASSERT_NOT_NULL(s);
+    cbm_store_upsert_project(s, "_tc_pr_precision_", "/tmp/pr_test");
+    cbm_node_t n1 = {.project = "_tc_pr_precision_", .label = "Function",
+                     .name = "fn_a", .qualified_name = "_tc_pr_precision_.fn_a",
+                     .file_path = "a.c"};
+    cbm_node_t n2 = {.project = "_tc_pr_precision_", .label = "Function",
+                     .name = "fn_b", .qualified_name = "_tc_pr_precision_.fn_b",
+                     .file_path = "b.c"};
+    cbm_store_upsert_node(s, &n1);
+    cbm_store_upsert_node(s, &n2);
+    /* Compute PageRank (even with no edges, nodes get baseline scores) */
+    cbm_pagerank_compute_default(s, "_tc_pr_precision_");
+    cbm_store_close(s);
+
+    cbm_mcp_server_t *srv = cbm_mcp_server_new(NULL);
+    ASSERT_NOT_NULL(srv);
+    char *resp = cbm_mcp_handle_tool(srv, "search_code_graph",
+        "{\"project\":\"_tc_pr_precision_\",\"sort_by\":\"relevance\",\"limit\":2}");
+    ASSERT_NOT_NULL(resp);
+    /* Pagerank values should NOT have more than ~8 characters (e.g. "4.72e-05")
+     * Check that we don't have 17-digit sequences like "0.00004717680769635863" */
+    ASSERT_NULL(strstr(resp, "000000000")); /* No 9+ consecutive zeros in pagerank */
+    free(resp);
+    cbm_mcp_server_free(srv);
+    (void)unlink(db_path);
+    PASS();
+}
+
+TEST(empty_db_not_treated_as_indexed) {
+    /* A DB file with schema but 0 nodes should NOT prevent re-indexing.
+     * Regression test: previously stat(db_path)==0 was enough to skip. */
+    char db_path[1024];
+    snprintf(db_path, sizeof(db_path), "%s/.cache/codebase-memory-mcp/_tc_empty_db_test_.db",
+             getenv("HOME"));
+    /* Create DB with schema but no data */
+    cbm_store_t *s = cbm_store_open_path(db_path);
+    ASSERT_NOT_NULL(s);
+    cbm_store_close(s);
+
+    /* Verify the file exists */
+    struct stat st;
+    ASSERT_EQ(stat(db_path, &st), 0);
+
+    /* Open it read-only and verify 0 nodes */
+    sqlite3 *db = NULL;
+    ASSERT_EQ(sqlite3_open_v2(db_path, &db, SQLITE_OPEN_READONLY, NULL), SQLITE_OK);
+    sqlite3_stmt *stmt = NULL;
+    int rc = sqlite3_prepare_v2(db, "SELECT count(*) FROM nodes", -1, &stmt, NULL);
+    ASSERT_EQ(rc, SQLITE_OK);
+    ASSERT_EQ(sqlite3_step(stmt), SQLITE_ROW);
+    int node_count = sqlite3_column_int(stmt, 0);
+    ASSERT_EQ(node_count, 0);
+    sqlite3_finalize(stmt);
+
+    /* Verify "SELECT 1 FROM nodes LIMIT 1" returns no rows (this is what db_has_content checks) */
+    rc = sqlite3_prepare_v2(db, "SELECT 1 FROM nodes LIMIT 1", -1, &stmt, NULL);
+    ASSERT_EQ(rc, SQLITE_OK);
+    ASSERT_NEQ(sqlite3_step(stmt), SQLITE_ROW); /* Should be SQLITE_DONE, not SQLITE_ROW */
+    sqlite3_finalize(stmt);
+    sqlite3_close(db);
+
+    (void)unlink(db_path);
+    PASS();
+}
+
 /* ── Suite registration ──────────────────────────────────── */

 SUITE(tool_consolidation) {
@@ -1497,4 +1631,9 @@ SUITE(tool_consolidation) {
    RUN_TEST(watcher_registered_after_index_repository);
    RUN_TEST(watcher_registered_on_resolve_store);
    RUN_TEST(watcher_not_registered_for_unknown_path);
+    /* Phase 10.2: Bug fixes and token optimization */
+    RUN_TEST(hidden_tools_returns_info_not_error);
+    RUN_TEST(compact_defaults_to_true);
+    RUN_TEST(pagerank_output_has_limited_precision);
+    RUN_TEST(empty_db_not_treated_as_indexed);
 }