diff --git a/packages/server/script-sandbox.js b/packages/server/script-sandbox.js
index d03b28a..f01ffa7 100644
--- a/packages/server/script-sandbox.js
+++ b/packages/server/script-sandbox.js
@@ -291,6 +291,10 @@ function createScriptSandbox({ log, script, workflowName }) {
   return sandbox;
 }
 
+function compileScriptSource(source, filename) {
+  return new vm.Script(wrapScriptSource(source, filename), { filename });
+}
+
 function loadCompiledScript(script) {
   const filePath = path.join(SCRIPTS_DIR, script);
   const { mtimeMs } = fs.statSync(filePath);
@@ -300,9 +304,7 @@ function loadCompiledScript(script) {
   }
 
   const source = fs.readFileSync(filePath, "utf8");
-  const compiled = new vm.Script(wrapScriptSource(source, script), {
-    filename: filePath,
-  });
+  const compiled = compileScriptSource(source, filePath);
   scriptCache.set(script, { compiled, mtimeMs });
   return compiled;
 }
@@ -320,3 +322,18 @@ export async function runScript(script, ctx, { log, workflowName }) {
   const fn = compiled.runInContext(sandbox);
   return await fn(ctx);
 }
+
+/**
+ * Evaluate script source in memory (dry-run). Does not read from disk or use the disk cache.
+ *
+ * @param {string} script
+ * @param {string} source
+ * @param {unknown} ctx
+ * @param {{ log: import("pino").Logger, workflowName: string }} opts
+ */
+export async function runScriptSource(script, source, ctx, { log, workflowName }) {
+  const compiled = compileScriptSource(source, script);
+  const sandbox = createScriptSandbox({ log, script, workflowName });
+  const fn = compiled.runInContext(sandbox);
+  return await fn(ctx);
+}
diff --git a/packages/server/scripts/fetch-binary.js b/packages/server/scripts/fetch-binary.js
new file mode 100644
index 0000000..d765fde
--- /dev/null
+++ b/packages/server/scripts/fetch-binary.js
@@ -0,0 +1,70 @@
+function ensureDataObject(ctx) {
+  if (ctx.data == null || typeof ctx.data !== "object" || Array.isArray(ctx.data)) {
+    ctx.data = {};
+  }
+}
+
+function filenameFromUrl(url) {
+  try {
+    const name = new URL(url).pathname.split("/").filter(Boolean).pop();
+    return name || "attachment";
+  } catch {
+    return "attachment";
+  }
+}
+
+function resolveUrl(ctx) {
+  const fromConfig = ctx.config?.url;
+  if (typeof fromConfig === "string" && fromConfig.length > 0) {
+    return fromConfig;
+  }
+
+  const urlVar = ctx.config?.urlVar;
+  if (typeof urlVar === "string" && urlVar.length > 0) {
+    const value = ctx.data?.[urlVar];
+    if (typeof value === "string" && value.length > 0) {
+      return value;
+    }
+  }
+
+  for (const key of ["attach", "url"]) {
+    const value = ctx.data?.[key];
+    if (typeof value === "string" && value.length > 0) {
+      return value;
+    }
+  }
+
+  return null;
+}
+
+export default async function fetchBinary(ctx) {
+  ensureDataObject(ctx);
+
+  const url = resolveUrl(ctx);
+  if (!url) {
+    throw new Error(
+      "fetch-binary: url is required (ctx.config.url, ctx.config.urlVar, ctx.data.attach, or ctx.data.url)",
+    );
+  }
+
+  const outputVar = typeof ctx.config?.outputVar === "string" && ctx.config.outputVar.length > 0
+    ? ctx.config.outputVar
+    : "file";
+
+  log.info({ url, outputVar }, "fetch-binary: fetching");
+  const response = await $axios.get(url, { responseType: "arraybuffer" });
+  const file = Buffer.from(response.data ?? []);
+  const contentType = String(response.headers?.["content-type"] ?? "application/octet-stream");
+  const filename = ctx.config?.filename || ctx.data.filename || filenameFromUrl(url);
+
+  ctx.data[outputVar] = file;
+  ctx.data.filename = filename;
+  ctx.data.contentType = contentType;
+
+  log.info(
+    { outputVar, filename, contentType, length: file.length },
+    "fetch-binary: saved",
+  );
+
+  return ctx;
+}
diff --git a/packages/server/scripts/ntfy.js b/packages/server/scripts/ntfy.js
index 065c4fe..d3e974b 100644
--- a/packages/server/scripts/ntfy.js
+++ b/packages/server/scripts/ntfy.js
@@ -1,20 +1,66 @@
+function ntfyHeaders(ctx) {
+  const headers = {};
+
+  if (ctx.data?.title) {
+    log.info("ntfy: setting title %s", ctx.data.title);
+    headers.Title = ctx.data.title;
+  }
+
+  return headers;
+}
+
 export default async function ntfy(ctx) {
-    log.info({ ctx }, "ntfy incoming context");
-    const headers = {}
-    
-    if(ctx.data?.title) {
-        log.info("ntfy: setting title %s", ctx.data.title);
-        headers.Title = ctx.data.title
+  const file = ctx.data?.file;
+  const hasFile = Buffer.isBuffer(file) || file instanceof Uint8Array;
+
+  log.info(
+    {
+      title: ctx.data?.title,
+      message: ctx.data?.message,
+      filename: ctx.data?.filename,
+      hasFile,
+      fileLength: hasFile ? file.length : 0,
+      attach: ctx.data?.attach,
+    },
+    "ntfy incoming context",
+  );
+
+  const headers = ntfyHeaders(ctx);
+  const ntfyUrl = ctx.config?.url || "https://ntfy.sh/scrunner";
+
+  if (hasFile) {
+    const filename = ctx.data?.filename || "attachment";
+    headers.Filename = filename;
+    if (ctx.data?.message) {
+      headers.Message = ctx.data.message;
+    }
+    if (ctx.data?.contentType) {
+      headers["Content-Type"] = ctx.data.contentType;
     }
 
-    const ntfyUrl = ctx.config?.url || "https://ntfy.sh/scrunner";
+    log.info(
+      { ntfyUrl, filename, length: file.length },
+      "ntfy uploading file",
+    );
+    await $axios.put(ntfyUrl, file, {
+      headers,
+      maxBodyLength: Infinity,
+      maxContentLength: Infinity,
+    });
+    return { sent: "true" };
+  }
 
-    log.info("ntfy sending message to %s", ntfyUrl);
-    const truncatedMessage = ctx.data?.message?.substring(0, 100);
-    log.info("ntfy messsage: %s", truncatedMessage);
+  if (ctx.data?.attach) {
+    log.info("ntfy: setting attach %s", ctx.data.attach);
+    headers.Attach = ctx.data.attach;
+  }
 
-    await $axios.post(ntfyUrl, ctx.data?.message || "Hello from scrunner", {
-        headers: headers
-    })
-    return {sent: "true"}
+  const truncatedMessage = ctx.data?.message?.substring(0, 100);
+  log.info("ntfy sending message to %s", ntfyUrl);
+  log.info("ntfy messsage: %s", truncatedMessage);
+
+  await $axios.post(ntfyUrl, ctx.data?.message || "Hello from scrunner", {
+    headers,
+  });
+  return { sent: "true" };
 }
diff --git a/packages/server/src/api/dry-run-logger.js b/packages/server/src/api/dry-run-logger.js
new file mode 100644
index 0000000..939ee34
--- /dev/null
+++ b/packages/server/src/api/dry-run-logger.js
@@ -0,0 +1,78 @@
+import pino from "pino";
+
+const LEVEL_TO_NUM = {
+  trace: 10,
+  debug: 20,
+  info: 30,
+  warn: 40,
+  error: 50,
+  fatal: 60,
+};
+
+/**
+ * Pino logger that collects log lines in memory (no SQLite / process logger).
+ *
+ * @returns {{ log: import("pino").Logger, logs: Array<{ ts: string, level: number, msg?: string | null, payload?: unknown }> }}
+ */
+export function createDryRunLogger() {
+  /** @type {Array<{ ts: string, level: number, msg?: string | null, payload?: unknown }>} */
+  const logs = [];
+
+  const dest = {
+    write(line) {
+      let record;
+      try {
+        record = JSON.parse(typeof line === "string" ? line : String(line));
+      } catch {
+        return;
+      }
+
+      const ts =
+        typeof record.time === "number"
+          ? new Date(record.time).toISOString()
+          : typeof record.time === "string"
+            ? record.time
+            : new Date().toISOString();
+
+      const level =
+        typeof record.level === "number"
+          ? record.level
+          : LEVEL_TO_NUM[record.level] ?? LEVEL_TO_NUM.info;
+
+      const { time: _time, level: _level, msg = null, ...rest } = record;
+      logs.push({
+        ts,
+        level,
+        msg,
+        payload: Object.keys(rest).length ? rest : null,
+      });
+    },
+  };
+
+  const log = pino({ level: "trace" }, dest);
+  return { log, logs };
+}
+
+/**
+ * @param {unknown} value
+ */
+export function safeSerialize(value) {
+  const seen = new WeakSet();
+  try {
+    return JSON.parse(
+      JSON.stringify(value, (_key, v) => {
+        if (typeof v === "bigint") return v.toString();
+        if (typeof v === "object" && v !== null) {
+          if (seen.has(v)) return "[Circular]";
+          seen.add(v);
+        }
+        return v;
+      }),
+    );
+  } catch (err) {
+    return {
+      error: "output could not be serialized",
+      detail: err instanceof Error ? err.message : String(err),
+    };
+  }
+}
diff --git a/packages/server/src/api/scripts.js b/packages/server/src/api/scripts.js
index 4c06684..48644a2 100644
--- a/packages/server/src/api/scripts.js
+++ b/packages/server/src/api/scripts.js
@@ -1,5 +1,6 @@
-import { clearScriptCache } from "../../script-sandbox.js";
+import { clearScriptCache, runScriptSource } from "../../script-sandbox.js";
 import * as fsStore from "../../fs-store.js";
+import { createDryRunLogger, safeSerialize } from "./dry-run-logger.js";
 
 /**
  * @param {{ referencedScripts: () => Set<string> }} registry
@@ -60,5 +61,51 @@ export default function scriptsPluginFactory(registry) {
       clearScriptCache();
       return { ok: true };
     });
+
+    fastify.post("/scripts/:name/dry-run", async (req, reply) => {
+      const { name } = /** @type {{ name: string }} */ (req.params);
+      try {
+        fsStore.assertScriptName(name);
+      } catch (err) {
+        return reply.code(err.statusCode ?? 400).send({ error: err.message });
+      }
+
+      const body = /** @type {{ content?: string, data?: unknown, config?: unknown }} */ (
+        req.body ?? {}
+      );
+      if (typeof body.content !== "string") {
+        return reply.code(400).send({ error: "content is required" });
+      }
+
+      const ctx = {
+        data: body.data ?? null,
+        config: body.config ?? null,
+      };
+
+      const { log, logs } = createDryRunLogger();
+      const started = Date.now();
+
+      try {
+        const output = await runScriptSource(name, body.content, ctx, {
+          log,
+          workflowName: "dry-run",
+        });
+        return {
+          status: "success",
+          output: safeSerialize(output),
+          error: null,
+          logs,
+          durationMs: Date.now() - started,
+        };
+      } catch (err) {
+        return {
+          status: "failed",
+          output: null,
+          error: err instanceof Error ? err.message : String(err),
+          logs,
+          durationMs: Date.now() - started,
+        };
+      }
+    });
   };
 }
diff --git a/packages/server/workflows/default/comic-monkeyuser-to-ntfy.yaml b/packages/server/workflows/default/comic-monkeyuser-to-ntfy.yaml
new file mode 100644
index 0000000..345725f
--- /dev/null
+++ b/packages/server/workflows/default/comic-monkeyuser-to-ntfy.yaml
@@ -0,0 +1,22 @@
+name: Comic - monkeyuser to ntfy
+scripts:
+  - script: fetch-html.js
+    config:
+      url: "https://www.monkeyuser.com/"
+      outputVar: "httpResponse"
+      selector: ".comic img"
+      jsonata: |
+        {"url": "https://www.monkeyuser.com" & [attributes.src][0], "title": [attributes.title][0]}
+  - script: jsonata.js
+    config:
+      expression: |
+        {"data": {"title": httpResponse.title, "message": httpResponse.title, "attach": httpResponse.url}}
+  - fetch-binary.js
+  - script: ntfy.js
+    config:
+      url: https://ntfy.sh/scrunner
+
+triggers:
+  - type: HTTP
+    method: POST
+    path: /new
diff --git a/packages/server/workflows/default/registers.yaml b/packages/server/workflows/default/registers.yaml
index 192c92e..d73f2f8 100644
--- a/packages/server/workflows/default/registers.yaml
+++ b/packages/server/workflows/default/registers.yaml
@@ -4,3 +4,4 @@ scripts:
   - manual-trigger.yaml
   - cron-example.yaml
   - fetch-devto.yaml
+  - comic-monkeyuser-to-ntfy.yaml
diff --git a/packages/web/src/App.jsx b/packages/web/src/App.jsx
index 1ac8ed1..1348da9 100644
--- a/packages/web/src/App.jsx
+++ b/packages/web/src/App.jsx
@@ -6,6 +6,8 @@ import { Layout } from "./components/Layout.jsx";
 import { AuthPage } from "./pages/AuthPage.jsx";
 import { HomePage } from "./pages/HomePage.jsx";
 import { ScriptsPage } from "./pages/ScriptsPage.jsx";
+import { ScriptDryRunPage } from "./pages/ScriptDryRunPage.jsx";
+import { ScriptEditPage, ScriptNewPage } from "./pages/ScriptEditPage.jsx";
 import { WorkflowsPage } from "./pages/WorkflowsPage.jsx";
 import { EventsPage } from "./pages/EventsPage.jsx";
 import { EventDetailPage } from "./pages/EventDetailPage.jsx";
@@ -45,6 +47,9 @@ export function App() {
       <Routes>
         <Route path="/" element={<HomePage />} />
         <Route path="/scripts" element={<ScriptsPage />} />
+        <Route path="/scripts/new" element={<ScriptNewPage />} />
+        <Route path="/scripts/:name/dry-run" element={<ScriptDryRunPage />} />
+        <Route path="/scripts/:name/edit" element={<ScriptEditPage />} />
         <Route path="/workflows" element={<WorkflowsPage />} />
         <Route path="/events" element={<EventsPage />} />
         <Route path="/events/:id" element={<EventDetailPage />} />
diff --git a/packages/web/src/api/hooks.js b/packages/web/src/api/hooks.js
index 44517cd..c0d7d32 100644
--- a/packages/web/src/api/hooks.js
+++ b/packages/web/src/api/hooks.js
@@ -105,6 +105,19 @@ export function useDeleteScript() {
   });
 }
 
+export function useDryRunScript() {
+  return useMutation({
+    mutationFn: async ({ name, content, data, config }) =>
+      (
+        await api.post(`/scripts/${encodeURIComponent(name)}/dry-run`, {
+          content,
+          data,
+          config,
+        })
+      ).data,
+  });
+}
+
 export function useWorkflows(owner) {
   return useQuery({
     queryKey: ["workflows", owner ?? "all"],
diff --git a/packages/web/src/components/CodeEditor.jsx b/packages/web/src/components/CodeEditor.jsx
index 234e771..9640d6a 100644
--- a/packages/web/src/components/CodeEditor.jsx
+++ b/packages/web/src/components/CodeEditor.jsx
@@ -1,19 +1,20 @@
 import Editor from "@monaco-editor/react";
 import { useTheme } from "../theme.jsx";
 
-export function CodeEditor({ language, value, onChange, height = "50vh" }) {
+export function CodeEditor({ language, value, onChange, height = "50vh", readOnly = false }) {
   const { theme } = useTheme();
   const isMobile = typeof window !== "undefined" && window.innerWidth < 768;
 
   return (
-    <div className="overflow-hidden rounded-box border border-base-300">
+    <div className="overflow-hidden rounded-box border border-base-300 h-full min-h-0">
       <Editor
         height={height}
         language={language}
         value={value}
-        onChange={(v) => onChange(v ?? "")}
+        onChange={readOnly ? undefined : (v) => onChange(v ?? "")}
         theme={theme === "dark" ? "vs-dark" : "light"}
         options={{
+          readOnly,
           minimap: { enabled: !isMobile },
           lineNumbers: "on",
           tabSize: 2,
diff --git a/packages/web/src/components/LogViewer.jsx b/packages/web/src/components/LogViewer.jsx
new file mode 100644
index 0000000..85dfb57
--- /dev/null
+++ b/packages/web/src/components/LogViewer.jsx
@@ -0,0 +1,49 @@
+import { useState } from "react";
+import { levelName } from "../lib/format.jsx";
+
+export function LogViewer({ logs = [], className = "" }) {
+  const [wordWrap, setWordWrap] = useState(true);
+
+  return (
+    <section className={`flex min-h-0 flex-col ${className}`}>
+      <div className="mb-2 flex shrink-0 items-center justify-between gap-2">
+        <h2 className="font-semibold text-sm">Logs</h2>
+        <label className="label cursor-pointer gap-2 py-0">
+          <span className="label-text text-sm">Word wrap</span>
+          <input
+            type="checkbox"
+            className="checkbox checkbox-sm"
+            checked={wordWrap}
+            onChange={(e) => setWordWrap(e.target.checked)}
+          />
+        </label>
+      </div>
+      <div className="mockup-code min-h-0 flex-1 overflow-auto text-xs">
+        {logs.length === 0 ? (
+          <div className="flex gap-3 px-5 py-0.5 font-mono opacity-50">
+            <span className="w-12 shrink-0 text-right">—</span>
+            <span>no logs</span>
+          </div>
+        ) : (
+          logs.map((l, i) => (
+            <div key={l.id ?? i} className="flex gap-3 px-5 py-0.5 font-mono">
+              <span className="w-12 shrink-0 text-right opacity-50">
+                {levelName(l.level)}
+              </span>
+              <span
+                className={
+                  wordWrap
+                    ? "min-w-0 flex-1 whitespace-pre-wrap break-words"
+                    : "whitespace-pre"
+                }
+              >
+                {l.ts} {l.msg ?? ""}
+                {l.payload ? ` ${JSON.stringify(l.payload)}` : ""}
+              </span>
+            </div>
+          ))
+        )}
+      </div>
+    </section>
+  );
+}
diff --git a/packages/web/src/components/MermaidDiagram.jsx b/packages/web/src/components/MermaidDiagram.jsx
index 93f748f..717d79d 100644
--- a/packages/web/src/components/MermaidDiagram.jsx
+++ b/packages/web/src/components/MermaidDiagram.jsx
@@ -46,7 +46,7 @@ export function MermaidDiagram({ chart, scriptIds = {} }) {
           el.style.cursor = "pointer";
           el.setAttribute("title", script);
           el.addEventListener("click", () => {
-            navigate(`/scripts?edit=${encodeURIComponent(script)}`);
+            navigate(`/scripts/${encodeURIComponent(script)}/edit`);
           });
         }
       })
diff --git a/packages/web/src/lib/script.js b/packages/web/src/lib/script.js
new file mode 100644
index 0000000..2b9f957
--- /dev/null
+++ b/packages/web/src/lib/script.js
@@ -0,0 +1,25 @@
+export const NEW_SCRIPT_TEMPLATE = `export default async function main(ctx) {
+  return ctx;
+}
+`;
+
+export const DEFAULT_INPUT_CONTEXT = `{
+  "data": {},
+  "config": {}
+}
+`;
+
+export function normalizeScriptName(name) {
+  const trimmed = name.trim();
+  if (!trimmed) return "";
+  return trimmed.endsWith(".js") ? trimmed : `${trimmed}.js`;
+}
+
+export function prettyJson(value) {
+  if (value === null || value === undefined) return "";
+  try {
+    return JSON.stringify(value, null, 2);
+  } catch {
+    return String(value);
+  }
+}
diff --git a/packages/web/src/pages/EventDetailPage.jsx b/packages/web/src/pages/EventDetailPage.jsx
index f7b1467..5537753 100644
--- a/packages/web/src/pages/EventDetailPage.jsx
+++ b/packages/web/src/pages/EventDetailPage.jsx
@@ -1,13 +1,12 @@
-import { useState } from "react";
 import { Link, useParams } from "react-router-dom";
 import { LuArrowLeft } from "react-icons/lu";
 import { useRun } from "../api/hooks.js";
-import { formatTime, levelName, StatusBadge } from "../lib/format.jsx";
+import { LogViewer } from "../components/LogViewer.jsx";
+import { formatTime, StatusBadge } from "../lib/format.jsx";
 
 export function EventDetailPage() {
   const { id } = useParams();
   const { data: run, isLoading, error } = useRun(id);
-  const [wordWrap, setWordWrap] = useState(true);
 
   if (isLoading) return <span className="loading loading-spinner loading-lg" />;
   if (error || !run) return <p className="text-error">Event not found</p>;
@@ -68,7 +67,7 @@ export function EventDetailPage() {
                 <tr key={s.id}>
                   <td>{s.step_index}</td>
                   <td className="font-mono">
-                    <Link className="link" to={`/scripts?edit=${encodeURIComponent(s.script)}`}>
+                    <Link className="link" to={`/scripts/${encodeURIComponent(s.script)}/edit`}>
                       {s.script}
                     </Link>
                   </td>
@@ -84,46 +83,7 @@ export function EventDetailPage() {
         </div>
       </section>
 
-      <section>
-        <div className="mb-2 flex items-center justify-between gap-2">
-          <h2 className="font-semibold">Logs</h2>
-          <label className="label cursor-pointer gap-2 py-0">
-            <span className="label-text text-sm">Word wrap</span>
-            <input
-              type="checkbox"
-              className="checkbox checkbox-sm"
-              checked={wordWrap}
-              onChange={(e) => setWordWrap(e.target.checked)}
-            />
-          </label>
-        </div>
-        <div className="mockup-code text-xs max-h-[50vh] overflow-auto">
-          {(run.logs ?? []).length === 0 ? (
-            <div className="flex gap-3 px-5 py-0.5 font-mono opacity-50">
-              <span className="w-12 shrink-0 text-right">—</span>
-              <span>no logs</span>
-            </div>
-          ) : (
-            run.logs.map((l) => (
-              <div key={l.id} className="flex gap-3 px-5 py-0.5 font-mono">
-                <span className="w-12 shrink-0 text-right opacity-50">
-                  {levelName(l.level)}
-                </span>
-                <span
-                  className={
-                    wordWrap
-                      ? "min-w-0 flex-1 whitespace-pre-wrap break-words"
-                      : "whitespace-pre"
-                  }
-                >
-                  {l.ts} {l.msg ?? ""}
-                  {l.payload ? ` ${JSON.stringify(l.payload)}` : ""}
-                </span>
-              </div>
-            ))
-          )}
-        </div>
-      </section>
+      <LogViewer logs={run.logs ?? []} />
     </div>
   );
 }
diff --git a/packages/web/src/pages/ScriptDryRunPage.jsx b/packages/web/src/pages/ScriptDryRunPage.jsx
new file mode 100644
index 0000000..15cef0c
--- /dev/null
+++ b/packages/web/src/pages/ScriptDryRunPage.jsx
@@ -0,0 +1,214 @@
+import { useEffect, useMemo, useState } from "react";
+import { Link, useLocation, useParams } from "react-router-dom";
+import { LuArrowLeft, LuPlay, LuSave } from "react-icons/lu";
+import { errorMessage } from "../api/client.js";
+import {
+  useDryRunScript,
+  useSaveScript,
+  useScript,
+} from "../api/hooks.js";
+import { CodeEditor } from "../components/CodeEditor.jsx";
+import { LogViewer } from "../components/LogViewer.jsx";
+import { StatusBadge } from "../lib/format.jsx";
+import {
+  DEFAULT_INPUT_CONTEXT,
+  NEW_SCRIPT_TEMPLATE,
+  normalizeScriptName,
+  prettyJson,
+} from "../lib/script.js";
+
+export function ScriptDryRunPage() {
+  const { name: rawName } = useParams();
+  const name = decodeURIComponent(rawName ?? "");
+  const location = useLocation();
+  const stateContent = location.state?.content;
+
+  const existing = useScript(name, stateContent == null);
+  const dryRun = useDryRunScript();
+  const save = useSaveScript();
+
+  const [content, setContent] = useState("");
+  const [inputJson, setInputJson] = useState(DEFAULT_INPUT_CONTEXT);
+  const [outputJson, setOutputJson] = useState("");
+  const [logs, setLogs] = useState([]);
+  const [runStatus, setRunStatus] = useState(null);
+  const [parseError, setParseError] = useState(null);
+  const [contentReady, setContentReady] = useState(false);
+
+  useEffect(() => {
+    if (stateContent != null) {
+      setContent(stateContent);
+      setContentReady(true);
+      return;
+    }
+    if (existing.isLoading) return;
+    if (existing.data?.content != null) {
+      setContent(existing.data.content);
+      setContentReady(true);
+      return;
+    }
+    if (existing.isError) {
+      setContent(NEW_SCRIPT_TEMPLATE);
+      setContentReady(true);
+    }
+  }, [stateContent, existing.data, existing.isLoading, existing.isError]);
+
+  const backHref = `/scripts/${encodeURIComponent(name)}/edit`;
+
+  const lastRun = dryRun.data;
+
+  useEffect(() => {
+    if (!lastRun) return;
+    setRunStatus(lastRun.status);
+    setLogs(lastRun.logs ?? []);
+    if (lastRun.status === "success") {
+      setOutputJson(prettyJson(lastRun.output));
+    } else {
+      setOutputJson(prettyJson({ error: lastRun.error ?? "run failed" }));
+    }
+  }, [lastRun]);
+
+  const runDisabledReason = useMemo(() => {
+    if (!contentReady) return "loading script";
+    if (!name) return "missing script name";
+    if (dryRun.isPending) return "running";
+    return null;
+  }, [contentReady, name, dryRun.isPending]);
+
+  function parseInputContext() {
+    let parsed;
+    try {
+      parsed = JSON.parse(inputJson);
+    } catch (err) {
+      throw new Error(err instanceof Error ? err.message : "invalid JSON");
+    }
+    if (parsed == null || typeof parsed !== "object" || Array.isArray(parsed)) {
+      throw new Error('input context must be a JSON object with "data" and/or "config"');
+    }
+    return {
+      data: "data" in parsed ? parsed.data : null,
+      config: "config" in parsed ? parsed.config : null,
+    };
+  }
+
+  function onRun() {
+    setParseError(null);
+    let ctx;
+    try {
+      ctx = parseInputContext();
+    } catch (err) {
+      setParseError(err instanceof Error ? err.message : String(err));
+      return;
+    }
+
+    dryRun.mutate({
+      name,
+      content,
+      data: ctx.data,
+      config: ctx.config,
+    });
+  }
+
+  function onSave() {
+    save.mutate({ name, content });
+  }
+
+  return (
+    <div className="flex h-[calc(100vh-5rem)] min-h-[32rem] flex-col gap-3">
+      <div className="flex shrink-0 flex-wrap items-center gap-2">
+        <Link to={backHref} className="btn btn-ghost btn-sm btn-square" aria-label="Back">
+          <LuArrowLeft className="size-4" />
+        </Link>
+        <h1 className="truncate font-mono text-lg font-semibold">{name}</h1>
+        <span className="badge badge-ghost badge-sm">dry run</span>
+        {runStatus ? <StatusBadge status={runStatus} /> : null}
+        {lastRun?.durationMs != null ? (
+          <span className="text-sm opacity-60">{lastRun.durationMs}ms</span>
+        ) : null}
+        <div className="flex-1" />
+        <button
+          type="button"
+          className="btn btn-primary btn-sm"
+          disabled={Boolean(runDisabledReason)}
+          onClick={onRun}
+        >
+          {dryRun.isPending ? (
+            <span className="loading loading-spinner loading-xs" />
+          ) : (
+            <LuPlay className="size-4" />
+          )}
+          Run
+        </button>
+        <button
+          type="button"
+          className="btn btn-outline btn-sm"
+          disabled={save.isPending || !contentReady}
+          onClick={onSave}
+        >
+          <LuSave className="size-4" />
+          Save
+        </button>
+      </div>
+
+      {parseError ? (
+        <p className="text-error text-sm shrink-0">{parseError}</p>
+      ) : null}
+      {dryRun.isError ? (
+        <p className="text-error text-sm shrink-0">{errorMessage(dryRun.error)}</p>
+      ) : null}
+      {save.isError ? (
+        <p className="text-error text-sm shrink-0">{errorMessage(save.error)}</p>
+      ) : null}
+      {save.isSuccess ? (
+        <p className="text-success text-sm shrink-0">Script saved</p>
+      ) : null}
+
+      <div className="grid min-h-0 flex-1 grid-cols-1 gap-3 lg:grid-cols-3">
+        <section className="flex min-h-0 flex-col gap-1">
+          <h2 className="shrink-0 text-sm font-semibold opacity-70">Input context</h2>
+          <div className="min-h-0 flex-1">
+            <CodeEditor
+              language="json"
+              value={inputJson}
+              onChange={setInputJson}
+              height="100%"
+            />
+          </div>
+        </section>
+
+        <section className="flex min-h-0 flex-col gap-1">
+          <h2 className="shrink-0 text-sm font-semibold opacity-70">Script</h2>
+          <div className="min-h-0 flex-1">
+            {!contentReady ? (
+              <div className="flex h-full items-center justify-center rounded-box border border-base-300">
+                <span className="loading loading-spinner" />
+              </div>
+            ) : (
+              <CodeEditor
+                language="javascript"
+                value={content}
+                onChange={setContent}
+                height="100%"
+              />
+            )}
+          </div>
+        </section>
+
+        <section className="flex min-h-0 flex-col gap-1">
+          <h2 className="shrink-0 text-sm font-semibold opacity-70">Output</h2>
+          <div className="min-h-0 flex-1">
+            <CodeEditor
+              language="json"
+              value={outputJson}
+              onChange={() => {}}
+              readOnly
+              height="100%"
+            />
+          </div>
+        </section>
+      </div>
+
+      <LogViewer logs={logs} className="h-48 shrink-0 lg:h-56" />
+    </div>
+  );
+}
diff --git a/packages/web/src/pages/ScriptEditPage.jsx b/packages/web/src/pages/ScriptEditPage.jsx
new file mode 100644
index 0000000..e5ca75b
--- /dev/null
+++ b/packages/web/src/pages/ScriptEditPage.jsx
@@ -0,0 +1,168 @@
+import { useEffect, useState } from "react";
+import { Link, useLocation, useNavigate, useParams } from "react-router-dom";
+import { LuArrowLeft, LuPlay, LuSave } from "react-icons/lu";
+import { errorMessage } from "../api/client.js";
+import { useSaveScript, useScript } from "../api/hooks.js";
+import { CodeEditor } from "../components/CodeEditor.jsx";
+import { NEW_SCRIPT_TEMPLATE, normalizeScriptName } from "../lib/script.js";
+
+export function ScriptNewPage() {
+  const navigate = useNavigate();
+  const location = useLocation();
+  const [name, setName] = useState("");
+  const [content, setContent] = useState(
+    location.state?.content ?? NEW_SCRIPT_TEMPLATE,
+  );
+  const save = useSaveScript();
+
+  function onSave(e) {
+    e.preventDefault();
+    const file = normalizeScriptName(name);
+    if (!file) return;
+    save.mutate(
+      { name: file, content },
+      {
+        onSuccess: () => navigate(`/scripts/${encodeURIComponent(file)}/edit`),
+      },
+    );
+  }
+
+  function openDryRun() {
+    const file = normalizeScriptName(name);
+    if (!file) return;
+    navigate(`/scripts/${encodeURIComponent(file)}/dry-run`, {
+      state: { content },
+    });
+  }
+
+  return (
+    <div className="flex h-[calc(100vh-5rem)] min-h-[32rem] flex-col gap-3">
+      <div className="flex shrink-0 flex-wrap items-center gap-2">
+        <Link to="/scripts" className="btn btn-ghost btn-sm btn-square" aria-label="Back">
+          <LuArrowLeft className="size-4" />
+        </Link>
+        <h1 className="text-xl font-semibold">New script</h1>
+        <div className="flex-1" />
+        <button
+          type="button"
+          className="btn btn-outline btn-sm"
+          disabled={!normalizeScriptName(name)}
+          onClick={openDryRun}
+        >
+          <LuPlay className="size-4" />
+          Dry run
+        </button>
+        <button
+          type="submit"
+          form="script-edit-form"
+          className="btn btn-primary btn-sm"
+          disabled={save.isPending || !normalizeScriptName(name)}
+        >
+          <LuSave className="size-4" />
+          Save
+        </button>
+      </div>
+
+      <form id="script-edit-form" onSubmit={onSave} className="flex min-h-0 flex-1 flex-col gap-3">
+        <input
+          className="input input-sm w-full max-w-md shrink-0"
+          placeholder="name.js"
+          value={name}
+          onChange={(e) => setName(e.target.value)}
+          required
+        />
+        <div className="min-h-0 flex-1">
+          <CodeEditor language="javascript" value={content} onChange={setContent} height="100%" />
+        </div>
+        {save.isError ? (
+          <p className="text-error text-sm shrink-0">{errorMessage(save.error)}</p>
+        ) : null}
+      </form>
+    </div>
+  );
+}
+
+export function ScriptEditPage() {
+  const { name: rawName } = useParams();
+  const name = decodeURIComponent(rawName ?? "");
+  const navigate = useNavigate();
+  const existing = useScript(name);
+  const save = useSaveScript();
+  const [content, setContent] = useState("");
+  const [contentReady, setContentReady] = useState(false);
+
+  useEffect(() => {
+    if (existing.isLoading) return;
+    if (existing.data?.content != null) {
+      setContent(existing.data.content);
+      setContentReady(true);
+    }
+  }, [existing.data, existing.isLoading]);
+
+  function onSave(e) {
+    e.preventDefault();
+    save.mutate({ name, content });
+  }
+
+  function openDryRun() {
+    navigate(`/scripts/${encodeURIComponent(name)}/dry-run`, {
+      state: { content },
+    });
+  }
+
+  if (existing.isLoading) {
+    return (
+      <div className="flex min-h-[12rem] items-center justify-center">
+        <span className="loading loading-spinner loading-lg" />
+      </div>
+    );
+  }
+
+  if (existing.isError) {
+    return (
+      <div className="space-y-3">
+        <Link to="/scripts" className="btn btn-ghost btn-sm">
+          <LuArrowLeft className="size-4" />
+          Back
+        </Link>
+        <p className="text-error">Script not found</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="flex h-[calc(100vh-5rem)] min-h-[32rem] flex-col gap-3">
+      <div className="flex shrink-0 flex-wrap items-center gap-2">
+        <Link to="/scripts" className="btn btn-ghost btn-sm btn-square" aria-label="Back">
+          <LuArrowLeft className="size-4" />
+        </Link>
+        <h1 className="truncate font-mono text-xl font-semibold">{name}</h1>
+        <div className="flex-1" />
+        <button type="button" className="btn btn-outline btn-sm" onClick={openDryRun}>
+          <LuPlay className="size-4" />
+          Dry run
+        </button>
+        <button
+          type="submit"
+          form="script-edit-form"
+          className="btn btn-primary btn-sm"
+          disabled={save.isPending || !contentReady}
+        >
+          <LuSave className="size-4" />
+          Save
+        </button>
+      </div>
+
+      <form id="script-edit-form" onSubmit={onSave} className="min-h-0 flex-1">
+        <CodeEditor language="javascript" value={content} onChange={setContent} height="100%" />
+      </form>
+
+      {save.isError ? (
+        <p className="text-error text-sm shrink-0">{errorMessage(save.error)}</p>
+      ) : null}
+      {save.isSuccess ? (
+        <p className="text-success text-sm shrink-0">Script saved</p>
+      ) : null}
+    </div>
+  );
+}
diff --git a/packages/web/src/pages/ScriptsPage.jsx b/packages/web/src/pages/ScriptsPage.jsx
index 8ca9307..909a845 100644
--- a/packages/web/src/pages/ScriptsPage.jsx
+++ b/packages/web/src/pages/ScriptsPage.jsx
@@ -1,89 +1,29 @@
-import { useEffect, useState } from "react";
-import { useSearchParams } from "react-router-dom";
-import { LuPencil, LuPlus, LuSave, LuTrash2, LuX } from "react-icons/lu";
+import { useState } from "react";
+import { Link, Navigate, useNavigate, useSearchParams } from "react-router-dom";
+import { LuPencil, LuPlay, LuPlus, LuTrash2 } from "react-icons/lu";
 import { errorMessage } from "../api/client.js";
-import {
-  useDeleteScript,
-  useSaveScript,
-  useScript,
-  useScripts,
-} from "../api/hooks.js";
-import { CodeEditor } from "../components/CodeEditor.jsx";
-
-const NEW_TEMPLATE = `export default async function main(ctx) {
-  return ctx;
-}
-`;
+import { useDeleteScript, useScripts } from "../api/hooks.js";
 
 export function ScriptsPage() {
-  const [params, setParams] = useSearchParams();
+  const [params] = useSearchParams();
+  const navigate = useNavigate();
   const editName = params.get("edit");
   const { data: scripts = [], isLoading } = useScripts();
-  const [mode, setMode] = useState(null);
-  const [name, setName] = useState("");
-  const [content, setContent] = useState("");
   const [confirmDelete, setConfirmDelete] = useState(null);
-
-  const existing = useScript(mode === "edit" ? name : null, mode === "edit");
-  const save = useSaveScript();
   const del = useDeleteScript();
 
-  useEffect(() => {
-    if (editName) {
-      setMode("edit");
-      setName(editName);
-    }
-  }, [editName]);
-
-  useEffect(() => {
-    if (mode === "edit" && existing.data?.content != null) {
-      setContent(existing.data.content);
-    }
-  }, [mode, existing.data]);
-
-  function openAdd() {
-    setMode("add");
-    setName("");
-    setContent(NEW_TEMPLATE);
-    setParams({});
-  }
-
-  function openEdit(script) {
-    setMode("edit");
-    setName(script);
-    setParams({ edit: script });
-  }
-
-  function closeForm() {
-    setMode(null);
-    setName("");
-    setContent("");
-    setParams({});
-  }
-
-  function onSave(e) {
-    e.preventDefault();
-    const file = name.endsWith(".js") ? name : `${name}.js`;
-    save.mutate(
-      { name: file, content },
-      {
-        onSuccess: () => {
-          setMode("edit");
-          setName(file);
-          setParams({ edit: file });
-        },
-      },
-    );
+  if (editName) {
+    return <Navigate to={`/scripts/${encodeURIComponent(editName)}/edit`} replace />;
   }
 
   return (
     <div className="space-y-4">
       <div className="flex items-center justify-between gap-2">
         <h1 className="text-xl font-semibold">Scripts</h1>
-        <button type="button" className="btn btn-primary btn-sm" onClick={openAdd}>
+        <Link to="/scripts/new" className="btn btn-primary btn-sm">
           <LuPlus className="size-4" />
           Add
-        </button>
+        </Link>
       </div>
 
       {isLoading ? (
@@ -94,22 +34,35 @@ export function ScriptsPage() {
             <thead>
               <tr>
                 <th>Name</th>
-                <th className="w-24" />
+                <th className="w-28" />
               </tr>
             </thead>
             <tbody>
               {scripts.map((s) => (
                 <tr key={s} className="hover">
-                  <td className="font-mono">{s}</td>
+                  <td className="font-mono">
+                    <Link className="link" to={`/scripts/${encodeURIComponent(s)}/edit`}>
+                      {s}
+                    </Link>
+                  </td>
                   <td className="text-right whitespace-nowrap">
                     <button
                       type="button"
                       className="btn btn-ghost btn-xs"
+                      title="Dry run"
+                      onClick={() =>
+                        navigate(`/scripts/${encodeURIComponent(s)}/dry-run`)
+                      }
+                    >
+                      <LuPlay className="size-4" />
+                    </button>
+                    <Link
+                      to={`/scripts/${encodeURIComponent(s)}/edit`}
+                      className="btn btn-ghost btn-xs"
                       title="Edit"
-                      onClick={() => openEdit(s)}
                     >
                       <LuPencil className="size-4" />
-                    </button>
+                    </Link>
                     <button
                       type="button"
                       className="btn btn-ghost btn-xs text-error"
@@ -126,38 +79,6 @@ export function ScriptsPage() {
         </div>
       )}
 
-      {mode ? (
-        <form onSubmit={onSave} className="space-y-3">
-          <div className="flex items-center justify-between">
-            <h2 className="font-semibold">{mode === "add" ? "New script" : name}</h2>
-            <button type="button" className="btn btn-ghost btn-sm btn-square" onClick={closeForm} aria-label="Close">
-              <LuX className="size-4" />
-            </button>
-          </div>
-          {mode === "add" ? (
-            <input
-              className="input input-sm w-full max-w-md"
-              placeholder="name.js"
-              value={name}
-              onChange={(e) => setName(e.target.value)}
-              required
-            />
-          ) : null}
-          {mode === "edit" && existing.isLoading ? (
-            <span className="loading loading-spinner" />
-          ) : (
-            <CodeEditor language="javascript" value={content} onChange={setContent} />
-          )}
-          {save.isError ? (
-            <p className="text-error text-sm">{errorMessage(save.error)}</p>
-          ) : null}
-          <button type="submit" className="btn btn-primary btn-sm" disabled={save.isPending}>
-            <LuSave className="size-4" />
-            Save
-          </button>
-        </form>
-      ) : null}
-
       {confirmDelete ? (
         <dialog className="modal modal-open">
           <div className="modal-box">
@@ -175,10 +96,7 @@ export function ScriptsPage() {
                 disabled={del.isPending}
                 onClick={() =>
                   del.mutate(confirmDelete, {
-                    onSuccess: () => {
-                      if (name === confirmDelete) closeForm();
-                      setConfirmDelete(null);
-                    },
+                    onSuccess: () => setConfirmDelete(null),
                   })
                 }
               >