diff --git a/src/cli/cli.c b/src/cli/cli.c
index f159f591..79a5e003 100644
--- a/src/cli/cli.c
+++ b/src/cli/cli.c
@@ -1143,6 +1143,10 @@ cbm_detected_agents_t cbm_detect_agents(const char *home_dir) {
     snprintf(path, sizeof(path), "%s/.kiro", home_dir);
     agents.kiro = dir_exists(path);
 
+    /* Junie (JetBrains): ~/.junie/ */
+    snprintf(path, sizeof(path), "%s/.junie", home_dir);
+    agents.junie = dir_exists(path);
+
     return agents;
 }
 
@@ -1679,6 +1683,17 @@ int cbm_remove_antigravity_mcp(const char *config_path) {
     return cbm_remove_editor_mcp(config_path);
 }
 
+/* ── Junie MCP config (JSON, same mcpServers format) ──────────── */
+
+int cbm_upsert_junie_mcp(const char *binary_path, const char *config_path) {
+    /* Junie (JetBrains) uses same mcpServers format as Cursor/Antigravity */
+    return cbm_install_editor_mcp(binary_path, config_path);
+}
+
+int cbm_remove_junie_mcp(const char *config_path) {
+    return cbm_remove_editor_mcp(config_path);
+}
+
 /* ── Claude Code pre-tool hooks ───────────────────────────────── */
 
 /* Matcher intentionally excludes Read: gating Read breaks Claude Code's
@@ -2934,6 +2949,7 @@ static void print_detected_agents(const cbm_detected_agents_t *a) {
         {a->cursor, "Cursor"},
         {a->openclaw, "OpenClaw"},
         {a->kiro, "Kiro"},
+        {a->junie, "Junie"},
     };
     printf("Detected agents:");
     bool any = false;
@@ -3247,6 +3263,16 @@ static void install_editor_agent_configs(const cbm_detected_agents_t *agents, co
         install_generic_agent_config("Kiro", binary_path, cp, NULL, dry_run,
                                      cbm_install_editor_mcp);
     }
+    if (agents->junie) {
+        char cp[CLI_BUF_1K];
+        char sd[CLI_BUF_1K];
+        snprintf(cp, sizeof(cp), "%s/.junie/mcp/mcp.json", home);
+        snprintf(sd, sizeof(sd), "%s/.junie/mcp", home);
+        if (!dry_run) {
+            cbm_mkdir_p(sd, CLI_OCTAL_PERM);
+        }
+        install_generic_agent_config("Junie", binary_path, cp, NULL, dry_run, cbm_upsert_junie_mcp);
+    }
 }
 
 static void cbm_install_agent_configs(const char *home, const char *binary_path, bool force,
@@ -3346,6 +3372,7 @@ char *cbm_build_install_plan_json(const char *home, const char *binary_path) {
         {det.cursor, "cursor"},
         {det.openclaw, "openclaw"},
         {det.kiro, "kiro"},
+        {det.junie, "junie"},
     };
 
     yyjson_mut_doc *doc = yyjson_mut_doc_new(NULL);
@@ -3720,6 +3747,12 @@ static void uninstall_editor_agents(const cbm_detected_agents_t *agents, const c
         uninstall_agent_mcp_instr((mcp_uninstall_args_t){"Kiro", cp, NULL}, dry_run,
                                   cbm_remove_editor_mcp);
     }
+    if (agents->junie) {
+        char cp[CLI_BUF_1K];
+        snprintf(cp, sizeof(cp), "%s/.junie/mcp/mcp.json", home);
+        uninstall_agent_mcp_instr((mcp_uninstall_args_t){"Junie", cp, NULL}, dry_run,
+                                  cbm_remove_junie_mcp);
+    }
 }
 
 int cbm_cmd_uninstall(int argc, char **argv) {
diff --git a/src/cli/cli.h b/src/cli/cli.h
index 9efe6789..52398d92 100644
--- a/src/cli/cli.h
+++ b/src/cli/cli.h
@@ -128,6 +128,7 @@ typedef struct {
     bool cursor;      /* ~/.cursor/ exists */
     bool openclaw;    /* ~/.openclaw/ exists */
     bool kiro;        /* ~/.kiro/ exists */
+    bool junie;       /* ~/.junie/ exists */
 } cbm_detected_agents_t;
 
 /* Detect which coding agents are installed.
@@ -155,6 +156,13 @@ int cbm_upsert_antigravity_mcp(const char *binary_path, const char *config_path)
 /* Remove CMM MCP entry from antigravity mcp_config.json. Returns 0 on success. */
 int cbm_remove_antigravity_mcp(const char *config_path);
 
+/* Junie (JetBrains): upsert MCP entry in ~/.junie/mcp/mcp.json (mcpServers format).
+ * Returns 0 on success. */
+int cbm_upsert_junie_mcp(const char *binary_path, const char *config_path);
+
+/* Remove CMM MCP entry from Junie mcp.json. Returns 0 on success. */
+int cbm_remove_junie_mcp(const char *config_path);
+
 /* ── Instructions file upsert ─────────────────────────────────── */
 
 /* Upsert a codebase-memory-mcp instruction section in a markdown file.
diff --git a/tests/test_cli.c b/tests/test_cli.c
index 0b78537c..99a50d07 100644
--- a/tests/test_cli.c
+++ b/tests/test_cli.c
@@ -695,6 +695,48 @@ TEST(cli_editor_mcp_uninstall) {
     PASS();
 }
 
+TEST(cli_junie_mcp_install_issue651) {
+    char tmpdir[256];
+    snprintf(tmpdir, sizeof(tmpdir), "/tmp/cli-mcp-XXXXXX");
+    if (!cbm_mkdtemp(tmpdir))
+        FAIL("cbm_mkdtemp failed");
+
+    char configpath[512];
+    snprintf(configpath, sizeof(configpath), "%s/.junie/mcp/mcp.json", tmpdir);
+
+    int rc = cbm_upsert_junie_mcp("/usr/local/bin/codebase-memory-mcp", configpath);
+    ASSERT_EQ(rc, 0);
+
+    const char *data = read_test_file(configpath);
+    ASSERT_NOT_NULL(data);
+    ASSERT(strstr(data, "mcpServers") != NULL);
+    ASSERT(strstr(data, "codebase-memory-mcp") != NULL);
+    ASSERT(strstr(data, "/usr/local/bin/codebase-memory-mcp") != NULL);
+
+    rc = cbm_upsert_junie_mcp("/usr/local/bin/codebase-memory-mcp", configpath);
+    ASSERT_EQ(rc, 0);
+
+    data = read_test_file(configpath);
+    ASSERT_NOT_NULL(data);
+    int count = 0;
+    const char *p = data;
+    while ((p = strstr(p, "\"codebase-memory-mcp\"")) != NULL) {
+        count++;
+        p += 20;
+    }
+    ASSERT_EQ(count, 1);
+
+    rc = cbm_remove_junie_mcp(configpath);
+    ASSERT_EQ(rc, 0);
+
+    data = read_test_file(configpath);
+    ASSERT_NOT_NULL(data);
+    ASSERT(strstr(data, "\"codebase-memory-mcp\"") == NULL);
+
+    test_rmdir_r(tmpdir);
+    PASS();
+}
+
 TEST(cli_gemini_mcp_install) {
     /* Port of TestGeminiMCPInstall */
     char tmpdir[256];
@@ -1774,6 +1816,22 @@ TEST(cli_detect_agents_finds_kiro) {
     PASS();
 }
 
+/* issue #651: Junie (~/.junie/) must be detected so install registers the
+ * MCP server in ~/.junie/mcp/mcp.json. */
+TEST(cli_detect_agents_finds_junie_issue651) {
+    char tmpdir[256];
+    snprintf(tmpdir, sizeof(tmpdir), "/tmp/cli-detect-XXXXXX");
+    if (!cbm_mkdtemp(tmpdir))
+        FAIL("cbm_mkdtemp failed");
+    char dir[512];
+    snprintf(dir, sizeof(dir), "%s/.junie", tmpdir);
+    test_mkdirp(dir);
+    cbm_detected_agents_t agents = cbm_detect_agents(tmpdir);
+    ASSERT_TRUE(agents.junie);
+    test_rmdir_r(tmpdir);
+    PASS();
+}
+
 TEST(cli_detect_agents_none_found) {
     char tmpdir[256];
     snprintf(tmpdir, sizeof(tmpdir), "/tmp/cli-detect-XXXXXX");
@@ -2692,6 +2750,7 @@ SUITE(cli) {
     RUN_TEST(cli_editor_mcp_idempotent);
     RUN_TEST(cli_editor_mcp_preserves_others);
     RUN_TEST(cli_editor_mcp_uninstall);
+    RUN_TEST(cli_junie_mcp_install_issue651);
     RUN_TEST(cli_gemini_mcp_install);
 
     /* VS Code MCP (2 tests — install_test.go) */
@@ -2756,6 +2815,7 @@ SUITE(cli) {
     RUN_TEST(cli_detect_agents_finds_antigravity);
     RUN_TEST(cli_detect_agents_finds_kilocode);
     RUN_TEST(cli_detect_agents_finds_kiro);
+    RUN_TEST(cli_detect_agents_finds_junie_issue651);
     RUN_TEST(cli_detect_agents_none_found);
 
     /* Codex MCP config upsert (3 tests — group B) */