feat(mcp): kebab__bulk_search tool (fb-42)

Exposes bulk multi-query search via MCP `bulk_search` tool:
- Input: { queries: [SearchInput shapes...] }, capped at 100
- Output: bulk_search_response.v1 with per-query results + summary
- Sequential execution reuses App instance for cache amortization
- Per-query errors embed error.v1 JSON; never aborts bulk call

Updates tool count from 7 to 8 in lib.rs comment + tools_list test.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-mcp/src/lib.rs

@@ -1,7 +1,7 @@
-//! MCP (Model Context Protocol) server over stdio. Exposes 7 tools
+//! MCP (Model Context Protocol) server over stdio. Exposes 8 tools
 //! (`search` / `ask` / `schema` / `doctor` / `ingest_file` / `ingest_stdin`
-//! / `fetch`) backed by `kebab-app` facade methods. Used by `kebab-cli`'s
-//! `Cmd::Mcp` arm.
+//! / `fetch` / `bulk_search`) backed by `kebab-app` facade methods. Used by
+//! `kebab-cli`'s `Cmd::Mcp` arm.
 //!
 //! See spec `docs/superpowers/specs/2026-05-07-p9-fb-30-mcp-server-design.md`.
 
@@ -67,6 +67,11 @@ pub fn build_tools_vec() -> Vec<Tool> {
             "Verbatim fetch — chunk / doc / span modes. Returns fetch_result.v1 with the indexed text (no LLM rewrite).",
             schema_for_type::<tools::fetch::FetchInput>(),
         ),
+        Tool::new(
+            "bulk_search",
+            "Bulk multi-query search — N queries per call (cap 100). Each query mirrors the `search` input shape; returns `bulk_search_response.v1` with per-query results + summary. Sequential execution reuses one App instance so cache / embedder cold-start cost amortizes.",
+            schema_for_type::<tools::bulk_search::BulkSearchInput>(),
+        ),
     ]
 }
 
@@ -170,6 +175,13 @@ impl ServerHandler for KebabHandler {
                 })
                 .await
             }
+            "bulk_search" => {
+                let args = request.arguments.unwrap_or_default();
+                self.spawn_tool(args, |state, input| {
+                    tools::bulk_search::handle(&state, input)
+                })
+                .await
+            }
             _other => Err(ErrorData::method_not_found::<
                 rmcp::model::CallToolRequestMethod,
             >()),

crates/kebab-mcp/src/tools/bulk_search.rs

@@ -0,0 +1,55 @@
+//! `bulk_search` tool — wraps `kebab_app::bulk_search_with_config`.
+//! Input: `{ queries: [<SearchInput shape>, ...] }`.
+//! Output: `bulk_search_response.v1` envelope (results + summary).
+
+use rmcp::model::CallToolResult;
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+
+use crate::error::{to_tool_error, to_tool_success};
+use crate::state::KebabAppState;
+
+#[derive(Debug, Deserialize, Serialize, JsonSchema)]
+pub struct BulkSearchInput {
+    /// Per-query inputs. Each item mirrors the single-query `search`
+    /// tool's input shape — `query` is required, all other fields are
+    /// optional and default to single-search defaults. Capped at 100
+    /// items; exceeding returns an `invalid_input` tool error without
+    /// running any query.
+    pub queries: Vec<serde_json::Value>,
+}
+
+pub fn handle(state: &KebabAppState, input: BulkSearchInput) -> CallToolResult {
+    let cfg_clone = (*state.config).clone();
+    match kebab_app::bulk_search_with_config(cfg_clone, input.queries) {
+        Ok((items, summary)) => {
+            let tagged_items: Vec<serde_json::Value> = items
+                .iter()
+                .map(|it| {
+                    let mut v = serde_json::to_value(it).unwrap_or(serde_json::Value::Null);
+                    if let serde_json::Value::Object(ref mut map) = v {
+                        map.insert(
+                            "schema_version".to_string(),
+                            serde_json::Value::String("bulk_search_item.v1".to_string()),
+                        );
+                    }
+                    v
+                })
+                .collect();
+            let envelope = serde_json::json!({
+                "schema_version": "bulk_search_response.v1",
+                "results": tagged_items,
+                "summary": {
+                    "total": summary.total,
+                    "succeeded": summary.succeeded,
+                    "failed": summary.failed,
+                },
+            });
+            match serde_json::to_string(&envelope) {
+                Ok(json) => to_tool_success(json),
+                Err(e) => to_tool_error(&anyhow::anyhow!(e)),
+            }
+        }
+        Err(e) => to_tool_error(&e),
+    }
+}

crates/kebab-mcp/src/tools/mod.rs

@@ -7,3 +7,4 @@ pub mod ask;
 pub mod ingest_file;
 pub mod ingest_stdin;
 pub mod fetch;
+pub mod bulk_search;

crates/kebab-mcp/tests/tools_list.rs

@@ -1,13 +1,13 @@
-//! Integration: `build_tools_vec` returns 7 tools with correct names and
+//! Integration: `build_tools_vec` returns 8 tools with correct names and
 //! inputSchema. Uses the extracted `pub fn build_tools_vec()` helper — no
 //! transport or RequestContext needed.
 
 use kebab_mcp::build_tools_vec;
 
 #[test]
-fn tools_list_returns_seven_tools() {
+fn tools_list_returns_eight_tools() {
     let tools = build_tools_vec();
-    assert_eq!(tools.len(), 7, "expected exactly 7 tools, got {}", tools.len());
+    assert_eq!(tools.len(), 8, "expected exactly 8 tools, got {}", tools.len());
 
     let names: Vec<&str> = tools.iter().map(|t| t.name.as_ref()).collect();
     assert!(names.contains(&"schema"), "missing 'schema' tool");
@@ -17,6 +17,7 @@ fn tools_list_returns_seven_tools() {
     assert!(names.contains(&"ingest_file"), "missing 'ingest_file' tool");
     assert!(names.contains(&"ingest_stdin"), "missing 'ingest_stdin' tool");
     assert!(names.contains(&"fetch"), "missing 'fetch' tool");
+    assert!(names.contains(&"bulk_search"), "missing 'bulk_search' tool");
 }
 
 #[test]