diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index 9718b8e..a0102ea 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -1,66 +1,79 @@
 import { useEffect, useMemo, useState } from "react";
 import {
+  MAX_CSV_BYTES,
   callSkill,
+  fileToBrowserUpload,
   loadAgentConfig,
   loadSession,
-  sampleArgs,
   signInUrl,
+  unwrapA2AResult,
 } from "./a2a.js";
 
+const SAMPLE_CSV = "month,revenue\nJanuary,100\nFebruary,120\nMarch,150\n";
+
 export function App() {
   const [config, setConfig] = useState(null);
   const [session, setSession] = useState(null);
-  const [selectedSkillName, setSelectedSkillName] = useState("");
-  const [argsText, setArgsText] = useState("{}");
+  const [analysisId, setAnalysisId] = useState("studio-csv-v1");
+  const [question, setQuestion] = useState("Which month has the highest revenue?");
+  const [csvText, setCsvText] = useState(SAMPLE_CSV);
+  const [file, setFile] = useState(null);
   const [result, setResult] = useState(null);
+  const [history, setHistory] = useState([]);
+  const [status, setStatus] = useState("Loading CSVAnswers...");
   const [error, setError] = useState(null);
   const [running, setRunning] = useState(false);
 
   useEffect(() => {
     loadAgentConfig()
-      .then((data) => {
-        setConfig(data);
-        const firstSkill = data.skills?.[0];
-        if (firstSkill) {
-          setSelectedSkillName(firstSkill.name);
-          setArgsText(JSON.stringify(sampleArgs(firstSkill), null, 2));
+      .then(async (loaded) => {
+        setConfig(loaded);
+        try {
+          const sessionData = await loadSession(loaded);
+          setSession(sessionData);
+          if (sessionData?.authenticated) await refreshHistory(loaded);
+        } catch {
+          setSession({ authenticated: false });
         }
-        return loadSession(data).catch(() => null);
+        setStatus(null);
       })
-      .then((sessionData) => setSession(sessionData))
-      .catch((err) => setError(err.message || String(err)));
+      .catch((err) => {
+        setError(err.message || String(err));
+        setStatus(null);
+      });
   }, []);
 
-  const selectedSkill = useMemo(
-    () => config?.skills?.find((skill) => skill.name === selectedSkillName),
-    [config, selectedSkillName],
-  );
+  const needsSignIn = Boolean(config?.auth?.invokeRequiresSession && !session?.authenticated);
+  const signInHref = useMemo(() => (config ? signInUrl(config) : null), [config]);
+  const maxKb = Math.round(MAX_CSV_BYTES / 1024);
 
-  const needsSignIn = Boolean(
-    config?.auth?.invokeRequiresSession && session && !session.authenticated,
-  );
-  const signInHref = useMemo(
-    () => (config && needsSignIn ? signInUrl(config) : null),
-    [config, needsSignIn],
-  );
-
-  function selectSkill(skill) {
-    setSelectedSkillName(skill.name);
-    setArgsText(JSON.stringify(sampleArgs(skill), null, 2));
-    setResult(null);
-    setError(null);
+  async function refreshHistory(activeConfig = config) {
+    if (!activeConfig) return;
+    try {
+      const response = await callSkill(activeConfig, "list_analyses", { limit: 10 });
+      const data = unwrapA2AResult(response);
+      if (data?.ok) setHistory(data.analyses || []);
+    } catch (err) {
+      if (!String(err.message || err).includes("session")) console.warn(err);
+    }
   }
 
-  async function runSkill(event) {
+  async function runAnalysis(event) {
     event.preventDefault();
-    if (!config || !selectedSkill) return;
+    if (!config) return;
     setRunning(true);
     setError(null);
     setResult(null);
     try {
-      const args = JSON.parse(argsText || "{}");
-      const data = await callSkill(config, selectedSkill.name, args);
+      const args = { analysis_id: analysisId.trim(), question: question.trim() };
+      const skill = file ? "analyze_csv_upload_base64" : "analyze_csv";
+      if (file) args.upload = await fileToBrowserUpload(file);
+      else args.csv_text = csvText;
+      const response = await callSkill(config, skill, args);
+      const data = unwrapA2AResult(response);
       setResult(data);
+      if (!data?.ok) setError(data?.message || data?.code || "CSV analysis failed.");
+      else await refreshHistory(config);
     } catch (err) {
       setError(err.message || String(err));
     } finally {
@@ -68,91 +81,133 @@ export function App() {
     }
   }
 
-  if (!config) {
-    return (
-      <main className="loading">
-        <p>{error || "Loading A2A agent contract..."}</p>
-      </main>
-    );
+  async function reopen(id = analysisId) {
+    if (!config || !id) return;
+    setRunning(true);
+    setError(null);
+    try {
+      const response = await callSkill(config, "get_analysis", { analysis_id: id.trim() });
+      const data = unwrapA2AResult(response);
+      setResult(data);
+      if (data?.ok) setAnalysisId(data.analysis_id);
+      else setError(data?.message || data?.code || "Analysis was not found.");
+    } catch (err) {
+      setError(err.message || String(err));
+    } finally {
+      setRunning(false);
+    }
   }
 
+  function onFileChange(event) {
+    const selected = event.target.files?.[0] || null;
+    setError(null);
+    if (selected && selected.size > MAX_CSV_BYTES) {
+      setError(`CSV upload must be at most ${maxKb} KB.`);
+      event.target.value = "";
+      setFile(null);
+      return;
+    }
+    setFile(selected);
+  }
+
+  if (status) return <main className="loading"><p>{status}</p></main>;
+
   return (
-    <main className="app-shell">
-      <aside className="sidebar">
+    <main className="shell">
+      <section className="hero" aria-labelledby="title">
         <div>
-          <p className="eyebrow">A2A packed app</p>
-          <h1>csv-answers-studio-v1</h1>
-          <p className="agent-meta">
-            {config.agent.name} v{config.agent.version}
+          <p className="eyebrow">A2A full-stack startup</p>
+          <h1 id="title">CSVAnswers Studio</h1>
+          <p className="lede">
+            Upload or paste a bounded CSV, ask for the highest numeric row, and reopen the saved, grounded answer after refresh.
           </p>
         </div>
-
-        <nav className="skill-list" aria-label="Agent skills">
-          {(config.skills || []).map((skill) => (
-            <button
-              className={skill.name === selectedSkillName ? "skill active" : "skill"}
-              key={skill.name}
-              onClick={() => selectSkill(skill)}
-              type="button"
-            >
-              <span>{skill.name}</span>
-              <small>{skill.stream ? "streaming" : "request"}</small>
-            </button>
-          ))}
-        </nav>
-
-        <div className="session">
-          <span>{session?.authenticated ? "Signed in" : needsSignIn ? "Signed out" : "Local session"}</span>
-          <strong>{session?.user?.email || session?.org?.slug || "dev@example.local"}</strong>
-          {/* Skills that spend the caller's LLM budget need a signed-in
-              visitor even when the page itself is public, so offer the way in
-              rather than failing at the first click. */}
-          {needsSignIn && signInHref ? (
-            <a className="signin" href={signInHref}>Sign in to run</a>
-          ) : null}
+        <div className="session-card" aria-live="polite">
+          <span>{session?.authenticated ? "Signed in" : "Sign-in required to run"}</span>
+          <strong>{session?.user?.email || session?.email || session?.org?.slug || "A2A Cloud user"}</strong>
+          {needsSignIn && signInHref ? <a href={signInHref}>Sign in securely</a> : null}
         </div>
-      </aside>
+      </section>
 
-      <section className="workbench">
-        <header className="toolbar">
-          <div>
-            <p className="eyebrow">Skill runner</p>
-            <h2>{selectedSkill?.name || "No skills found"}</h2>
-          </div>
-          <a href={config.docs.base} rel="noreferrer" target="_blank">
-            Docs
-          </a>
-        </header>
+      {error ? <div className="alert" role="alert">{error}</div> : null}
 
-        {selectedSkill ? (
-          <form className="runner" onSubmit={runSkill}>
+      <section className="grid">
+        <form className="card workflow" onSubmit={runAnalysis}>
+          <div className="field-row">
             <label>
-              Arguments JSON
-              <textarea
-                spellCheck="false"
-                value={argsText}
-                onChange={(event) => setArgsText(event.target.value)}
-              />
+              Analysis ID
+              <input value={analysisId} onChange={(event) => setAnalysisId(event.target.value)} maxLength={128} required />
             </label>
-            <button disabled={running} type="submit">
-              {running ? "Running..." : `Run ${selectedSkill.name}`}
+            <button type="button" className="secondary" onClick={() => reopen()} disabled={running || needsSignIn}>
+              Reopen saved
             </button>
-          </form>
-        ) : (
-          <p className="empty">Add a `@a2a.tool` to your agent to make it callable here.</p>
-        )}
+          </div>
 
-        <section className="panels">
-          <div className="panel">
-            <h3>Input schema</h3>
-            <pre>{JSON.stringify(selectedSkill?.input_schema || {}, null, 2)}</pre>
-          </div>
-          <div className="panel">
-            <h3>Result</h3>
-            <pre>{error || JSON.stringify(result, null, 2) || "No run yet."}</pre>
+          <label>
+            Question
+            <input value={question} onChange={(event) => setQuestion(event.target.value)} required />
+          </label>
+
+          <label>
+            Paste CSV text <small>UTF-8, max {maxKb} KB, {"≤"}500 rows</small>
+            <textarea
+              value={csvText}
+              onChange={(event) => { setCsvText(event.target.value); setFile(null); }}
+              disabled={Boolean(file)}
+              spellCheck="false"
+            />
+          </label>
+
+          <label className="upload">
+            Or choose CSV file
+            <input accept=".csv,text/csv,text/plain" type="file" onChange={onFileChange} />
+            {file ? <span>{file.name} · {Math.ceil(file.size / 1024)} KB · browser base64 bridge</span> : <span>External clients can also use typed FileUpload.</span>}
+          </label>
+
+          <div className="actions">
+            <button type="submit" disabled={running || needsSignIn}>{running ? "Analyzing..." : "Analyze and save"}</button>
+            <button type="button" className="ghost" onClick={() => { setCsvText(SAMPLE_CSV); setFile(null); setQuestion("Which month has the highest revenue?"); }}>
+              Load sample
+            </button>
           </div>
+        </form>
+
+        <section className="card result" aria-live="polite">
+          <p className="eyebrow">Grounded answer</p>
+          {result?.ok ? (
+            <>
+              <h2>{result.answer}</h2>
+              <dl className="facts">
+                <div><dt>Rows</dt><dd>{result.row_count}</dd></div>
+                <div><dt>Numeric column</dt><dd>{result.numeric_column}</dd></div>
+                <div><dt>Receipt</dt><dd>{result.receipt_id || "pending"}</dd></div>
+              </dl>
+              <h3>Source rows</h3>
+              <div className="table-wrap"><table><tbody>{result.source_rows?.map((row) => Object.entries(row.values || {}).map(([key, value]) => (
+                <tr key={`${row.row_number}-${key}`}><th>{key}</th><td>{String(value)}</td></tr>
+              )))}</tbody></table></div>
+              <h3>Chart-ready data</h3>
+              <div className="bars">
+                {(result.chart_data || []).map((point) => {
+                  const max = Math.max(...(result.chart_data || []).map((p) => p.value), 1);
+                  return <div className="bar" key={point.label}><span>{point.label}</span><meter min="0" max={max} value={point.value}>{point.value}</meter><strong>{point.value}</strong></div>;
+                })}
+              </div>
+            </>
+          ) : result ? (
+            <div className="empty"><h2>{result.code || "Unable to analyze CSV"}</h2><p>{result.message}</p></div>
+          ) : (
+            <div className="empty"><h2>No analysis yet</h2><p>Run the sample fixture or upload your own CSV to see the answer, rows, and chart data.</p></div>
+          )}
         </section>
       </section>
+
+      <section className="card history">
+        <div className="history-head"><div><p className="eyebrow">Saved analyses</p><h2>Reload-safe history</h2></div><button className="secondary" onClick={() => refreshHistory()} disabled={running || needsSignIn}>Refresh</button></div>
+        {history.length ? (
+          <ul>{history.map((item) => <li key={item.analysis_id}><button type="button" onClick={() => reopen(item.analysis_id)}><strong>{item.analysis_id}</strong><span>{item.answer}</span></button></li>)}</ul>
+        ) : <p className="muted">Saved analyses appear here after a successful run for this signed-in user.</p>}
+      </section>
     </main>
   );
 }