feat(agent): search_documents tool — the model can grep the indexed documents for an exact string

frontend/assets/app.js

@@ -55,20 +55,22 @@
  * "New chat" (#new-chat-btn — bound by the shared header module,
  * phase 34 task 02) clears the key + the list back to the empty state.
  *
- * Agent tool calls (phase 37, PLAN §4 extension): a grounded turn may
- * call the two server-side document tools (list_documents /
- * read_document, budgeted server-side). Each call streams a `tool` SSE
- * frame, and the UI shows the "calling tool" state IN ADDITION to
- * "thinking": the UI state itself stays "thinking" (the button stays
- * the enabled "Stop" control — phase 48 — never stale, PLAN §7.4) while
- * the STATUS LABELS change — the #send-status + typing-indicator labels
- * say what Brain is doing ("…is listing documents" /
- * "…is reading source/path" — the name prefix resolves from
- * window.BOR_BRAND at call time, phase 39) — the button no longer
- * relabels to "Calling tool…" (phase 48, owner-locked: it stays "Stop"
- * for the whole turn) — and a visible `.tool-call` line (own icon +
- * accent color, distinct from the brand-ink Thinking block) is appended
- * above the answer, one per call, in order.
+ * Agent tool calls (phase 37, PLAN §4 extension; phase 68 added
+ * search_documents): a grounded turn may call the three server-side
+ * document tools (list_documents / read_document / search_documents,
+ * bounded only by the round cap — phases 45/68). Each call streams a
+ * `tool` SSE frame, and the UI shows the "calling tool" state IN
+ * ADDITION to "thinking": the UI state itself stays "thinking" (the
+ * button stays the enabled "Stop" control — phase 48 — never stale,
+ * PLAN §7.4) while the STATUS LABELS change — the #send-status +
+ * typing-indicator labels say what Brain is doing ("…is listing
+ * documents" / "…is reading source/path" / "…is searching for
+ * pattern" — the name prefix resolves from window.BOR_BRAND at call
+ * time, phase 39) — the button no longer relabels to "Calling tool…"
+ * (phase 48, owner-locked: it stays "Stop" for the whole turn) — and a
+ * visible `.tool-call` line (own icon + accent color, distinct from
+ * the brand-ink Thinking block) is appended above the answer, one per
+ * call, in order.
  * Append-only like thinking: frames are tolerated in any interleaving
  * (a frame after the first delta just appends — the agent loop never
  * emits one, but it must not crash). The turn record persists an
@@ -808,9 +810,9 @@ function closeThinkingBlock(wrap) {
  * interleaving with thinking frames, even after the first delta (the
  * agent loop never emits one, but a late frame must not crash) — just
  * append another line, in order. The SAME helper re-renders the
- * persisted lines on restore (phase 14 convention): the path argument
- * goes through textContent, so nothing HTML-shaped can come from
- * storage. Lines are not interactive (no focus targets). */
+ * persisted lines on restore (phase 14 convention): the path/pattern
+ * argument goes through textContent, so nothing HTML-shaped can come
+ * from storage. Lines are not interactive (no focus targets). */
 function appendToolLine(wrap, name, argument) {
   const body = wrap?.querySelector?.(".msg-body");
   if (!body) return;
@@ -832,6 +834,11 @@ function appendToolLine(wrap, name, argument) {
     const code = document.createElement("code");
     code.textContent = argument; // the path is data, never markup
     line.appendChild(code);
+  } else if (name === "search_documents" && argument) {
+    line.textContent = "🔎 Searching for ";
+    const code = document.createElement("code");
+    code.textContent = argument; // the pattern is data, never markup
+    line.appendChild(code);
   } else {
     line.textContent = "🔎 Listing documents";
   }
@@ -1936,7 +1943,9 @@ async function runTurn(text, { reask = false } = {}) {
         const toolStatus =
           name === "read_document" && argument
             ? `${brand()} is reading ${argument}`
-            : `${brand()} is listing documents`;
+            : name === "search_documents" && argument
+              ? `${brand()} is searching for ${argument}`
+              : `${brand()} is listing documents`;
         if (uiState === UI_STATE.thinking) {
           sendStatus.textContent = toolStatus;
           document