feat: add forms domain and durable window binding (v0.9.0) (#14)

- Add forms domain with a universal field setter that auto-detects element
  type and fires framework-compatible input events (React native-setter trick)
- Add window-binding helper to capture and bind the real Chrome windowId as the
  session's durable window identity on every new-window code path
- Wire supporting changes across CDP session/ownership, client, navigate,
  isolated-tab, prompt, and state
- Add manual tests for forms and window binding
- Bump version 0.8.3 -> 0.9.0

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

3 files changed, 385 insertions, 11 deletions

diff --git a/src/domains/forms.ts b/src/domains/forms.ts
new file mode 100644
index 0000000..1d83ba6
--- /dev/null
+++ b/src/domains/forms.ts
@@ -0,0 +1,355 @@
+import { Type } from "typebox";
+import type { BrowserClient } from "../client";
+import { type Result, err, ok } from "../util/result";
+import { defineBrowserTool, type ToolErr, type ToolOk } from "../util/tool";
+
+// ── Page-side functions ──────────────────────────────────────────────────────
+// These run inside the page via Runtime.callFunctionOn with `this` bound to the
+// resolved element. They are NOT string-interpolated with user data — the value
+// is passed as a structured `arguments` entry, so safeJs is unnecessary here.
+
+/**
+ * Universal field setter. Auto-detects the element type and applies the right
+ * strategy, then reads the resulting value back so the caller can confirm.
+ *
+ * The <input>/<textarea> branch uses the "native setter" trick: React (and
+ * other frameworks) overload the element's `value` setter to track state, so a
+ * plain `el.value = x` updates the DOM but not the framework. Calling the
+ * prototype's original setter and then dispatching a bubbling `input` event is
+ * what makes React's onChange fire.
+ */
+const FILL_FN = `
+function(value) {
+  const el = this;
+  if (!el || el.nodeType !== 1) return { ok: false, reason: "ref does not point to an element" };
+  if (el.disabled) return { ok: false, reason: "element is disabled" };
+  const tag = (el.tagName || "").toLowerCase();
+  const type = (el.type || "").toLowerCase();
+  try { el.focus(); } catch (e) {}
+  const fire = function(t) { el.dispatchEvent(new Event(t, { bubbles: true })); };
+
+  if (tag === "select") {
+    const want = String(value);
+    let matched = null;
+    for (let i = 0; i < el.options.length; i++) {
+      const o = el.options[i];
+      if (o.value === want || o.label === want || o.text === want) { matched = o; break; }
+    }
+    if (!matched) {
+      const opts = [];
+      for (let i = 0; i < el.options.length; i++) opts.push({ value: el.options[i].value, text: el.options[i].text });
+      return { ok: false, reason: "no matching option", kind: "select", options: opts };
+    }
+    el.value = matched.value;
+    fire("input"); fire("change");
+    return { ok: true, kind: "select", value: el.value, text: matched.text };
+  }
+
+  if (tag === "input" && (type === "checkbox" || type === "radio")) {
+    const want = value === true || value === "true" || value === "on" || value === 1;
+    if (el.checked !== want) {
+      try { el.click(); } catch (e) {}
+      if (el.checked !== want) { el.checked = want; fire("input"); fire("change"); }
+    }
+    return { ok: true, kind: type, checked: el.checked };
+  }
+
+  if (el.isContentEditable) {
+    el.textContent = String(value);
+    fire("input"); fire("change");
+    return { ok: true, kind: "contenteditable", value: el.textContent };
+  }
+
+  if (tag === "input" || tag === "textarea") {
+    const proto = tag === "textarea" ? window.HTMLTextAreaElement.prototype : window.HTMLInputElement.prototype;
+    const desc = Object.getOwnPropertyDescriptor(proto, "value");
+    if (desc && desc.set) desc.set.call(el, String(value));
+    else el.value = String(value);
+    fire("input"); fire("change");
+    return { ok: true, kind: tag, value: el.value };
+  }
+
+  return { ok: false, reason: "element is not a fillable field (tag=" + tag + ")" };
+}`;
+
+/** Specialized <select> setter — matches by value first, then by label/text. */
+const SELECT_FN = `
+function(value, label) {
+  const el = this;
+  if (!el || (el.tagName || "").toLowerCase() !== "select") return { ok: false, reason: "ref is not a <select> element" };
+  if (el.disabled) return { ok: false, reason: "select is disabled" };
+  let matched = null;
+  for (let i = 0; i < el.options.length; i++) {
+    const o = el.options[i];
+    if (value != null && o.value === String(value)) { matched = o; break; }
+    if (label != null && (o.text === String(label) || o.label === String(label))) { matched = o; break; }
+  }
+  if (!matched) {
+    const opts = [];
+    for (let i = 0; i < el.options.length; i++) opts.push({ value: el.options[i].value, text: el.options[i].text });
+    return { ok: false, reason: "no matching option", options: opts };
+  }
+  try { el.focus(); } catch (e) {}
+  el.value = matched.value;
+  el.dispatchEvent(new Event("input", { bubbles: true }));
+  el.dispatchEvent(new Event("change", { bubbles: true }));
+  return { ok: true, value: el.value, text: matched.text };
+}`;
+
+/** Specialized checkbox/radio setter — only acts when the state differs. */
+const CHECK_FN = `
+function(checked) {
+  const el = this;
+  const tag = (el.tagName || "").toLowerCase();
+  const type = (el.type || "").toLowerCase();
+  if (tag !== "input" || (type !== "checkbox" && type !== "radio")) return { ok: false, reason: "ref is not a checkbox or radio" };
+  if (el.disabled) return { ok: false, reason: "element is disabled" };
+  const want = checked === true;
+  let changed = false;
+  if (el.checked !== want) {
+    try { el.click(); } catch (e) {}
+    if (el.checked !== want) { el.checked = want; el.dispatchEvent(new Event("change", { bubbles: true })); }
+    changed = true;
+  }
+  return { ok: true, checked: el.checked, changed: changed };
+}`;
+
+// ── Resolver ─────────────────────────────────────────────────────────────────
+
+/** Shape returned by the page-side functions above. */
+type PageResult = {
+  readonly ok: boolean;
+  readonly reason?: string;
+  readonly kind?: string;
+  readonly value?: unknown;
+  readonly text?: string;
+  readonly checked?: boolean;
+  readonly changed?: boolean;
+  readonly options?: ReadonlyArray<{ value: string; text: string }>;
+};
+
+/**
+ * Resolve a ref (CDP backendDOMNodeId) to a live JS handle and invoke a
+ * page-side function on it. DOM + Runtime are enabled on every session
+ * (see cdp/session.ts enableDomains), so no extra setup is required.
+ */
+const resolveAndCall = async (
+  client: BrowserClient,
+  ref: number,
+  functionDeclaration: string,
+  args: ReadonlyArray<unknown>,
+): Promise<Result<PageResult, ToolErr>> => {
+  const session = client.session();
+
+  const resolved = await session.call("DOM.resolveNode", { backendNodeId: ref });
+  if (!resolved.success) {
+    return err({
+      kind: "invalid_state",
+      message: `ref ${ref} could not be resolved — the page may have changed. Re-run browser_snapshot to get fresh refs.`,
+      details: { ref },
+    });
+  }
+  const objectId = (resolved.data as { object?: { objectId?: string } }).object?.objectId;
+  if (objectId === undefined) {
+    return err({
+      kind: "invalid_state",
+      message: `ref ${ref} resolved to no JS object — re-run browser_snapshot to get fresh refs.`,
+      details: { ref },
+    });
+  }
+
+  try {
+    const called = await session.call("Runtime.callFunctionOn", {
+      objectId,
+      functionDeclaration,
+      arguments: args.map((v) => ({ value: v })),
+      returnByValue: true,
+      awaitPromise: true,
+    });
+    if (!called.success) return err({ kind: "cdp_error", message: called.error.message, details: { ref } });
+    const data = called.data as { result?: { value?: unknown }; exceptionDetails?: unknown };
+    if (data.exceptionDetails !== undefined) {
+      return err({ kind: "cdp_error", message: `page function threw: ${JSON.stringify(data.exceptionDetails)}`, details: { ref } });
+    }
+    const value = data.result?.value;
+    if (typeof value !== "object" || value === null) {
+      return err({ kind: "internal", message: "page function returned no result object", details: { ref } });
+    }
+    return ok(value as PageResult);
+  } finally {
+    // Best-effort: release the remote handle so it can be GC'd. Failure is
+    // harmless (the page may have navigated), so we ignore the result.
+    await session.call("Runtime.releaseObject", { objectId });
+  }
+};
+
+/** Drop the `ok` flag before stashing a page result in tool `details` — the
+ *  tool-result envelope reserves `ok` for its own success discriminant. */
+const detailsOf = (ref: number, res: PageResult, extra?: Readonly<Record<string, unknown>>): Readonly<Record<string, unknown>> => {
+  const { ok: _ok, ...rest } = res;
+  return { ref, ...rest, ...(extra ?? {}) };
+};
+
+// ── Tools ────────────────────────────────────────────────────────────────────
+
+const FieldValue = Type.Union([Type.String(), Type.Boolean()], {
+  description: "Value to set. String for text inputs / textareas / selects / contenteditable; boolean for checkboxes & radios.",
+});
+
+const FillArgs = Type.Object({
+  ref: Type.Integer({ description: "Element ref from browser_snapshot ([ref=N])." }),
+  value: FieldValue,
+});
+
+export const fillTool = defineBrowserTool({
+  name: "browser_fill",
+  label: "Browser Fill",
+  description:
+    "Fill a single form field by ref. Auto-detects input/textarea/select/checkbox/radio/contenteditable, clears then sets the value, fires input+change events (drives React/Vue controlled inputs correctly), and reads the value back to confirm. Get the ref from browser_snapshot's [ref=N].",
+  promptSnippet: "Fill a form field by ref (text, select, checkbox) — React-safe, self-confirming",
+  promptGuidelines: [
+    "Get the ref from browser_snapshot's [ref=N] for the target field. No click-to-focus needed.",
+    "value is a string for text fields/selects/contenteditable, or a boolean for checkboxes/radios.",
+    "The result reports the value the field actually holds after filling — check it matches what you intended.",
+    "For autocomplete/typeahead that needs real keystrokes, click the field's @(x,y) then use browser_type instead.",
+    "If a ref no longer resolves, re-run browser_snapshot to get fresh refs.",
+  ],
+  parameters: FillArgs,
+  async handler(args, { client }): Promise<Result<ToolOk, ToolErr>> {
+    const r = await resolveAndCall(client, args.ref, FILL_FN, [args.value]);
+    if (!r.success) return r;
+    const res = r.data;
+    if (!res.ok) {
+      return err({ kind: "invalid_state", message: `Could not fill ref ${args.ref}: ${res.reason ?? "unknown reason"}`, details: detailsOf(args.ref, res) });
+    }
+    const wanted = typeof args.value === "boolean" ? undefined : String(args.value);
+    const got = res.value !== undefined ? String(res.value) : undefined;
+    const mismatch = wanted !== undefined && got !== undefined && got !== wanted;
+    let text: string;
+    if (mismatch) {
+      text = `Filled ref ${args.ref}, but it now reads ${JSON.stringify(got)} (wanted ${JSON.stringify(wanted)})`;
+    } else if (got !== undefined) {
+      text = `Filled ref ${args.ref} = ${JSON.stringify(got)}`;
+    } else if (res.checked !== undefined) {
+      text = `Filled ref ${args.ref} (checked=${res.checked})`;
+    } else {
+      text = `Filled ref ${args.ref}`;
+    }
+    return ok({ text, details: detailsOf(args.ref, res, { mismatch }) });
+  },
+});
+
+const FillFormArgs = Type.Object({
+  fields: Type.Array(
+    Type.Object({
+      ref: Type.Integer({ description: "Element ref from browser_snapshot ([ref=N])." }),
+      value: FieldValue,
+    }),
+    { minItems: 1, description: "Fields to fill in one batch, each by ref." },
+  ),
+});
+
+export const fillFormTool = defineBrowserTool({
+  name: "browser_fill_form",
+  label: "Browser Fill Form",
+  description:
+    "Fill multiple form fields in one call — the efficient way to complete a form. Each field is { ref, value }; refs come from browser_snapshot's [ref=N]. Handles text inputs, textareas, selects, checkboxes, radios, and contenteditable, drives React/Vue controlled inputs correctly, and reports the resulting value of every field.",
+  promptSnippet: "Fill many form fields at once by ref — React-safe, self-confirming",
+  promptGuidelines: [
+    "Preferred for forms: snapshot once, then fill all fields in a single browser_fill_form call.",
+    "Each field: { ref, value }. value is a string for text/select/contenteditable, boolean for checkbox/radio.",
+    "The result summarizes how many fields filled cleanly and flags any value mismatches or per-field errors.",
+    "Re-run browser_snapshot afterwards to verify the form state if needed.",
+  ],
+  parameters: FillFormArgs,
+  async handler(args, { client }): Promise<Result<ToolOk, ToolErr>> {
+    const results: Array<Readonly<Record<string, unknown>>> = [];
+    let okCount = 0;
+    const issues: string[] = [];
+    for (const f of args.fields) {
+      const r = await resolveAndCall(client, f.ref, FILL_FN, [f.value]);
+      if (!r.success) {
+        results.push({ ref: f.ref, ok: false, error: r.error.message });
+        issues.push(`ref ${f.ref} (${r.error.message})`);
+        continue;
+      }
+      const res = r.data;
+      const wanted = typeof f.value === "boolean" ? undefined : String(f.value);
+      const got = res.value !== undefined ? String(res.value) : undefined;
+      const mismatch = wanted !== undefined && got !== undefined && got !== wanted;
+      const fieldOk = res.ok === true && !mismatch;
+      if (fieldOk) okCount++;
+      else issues.push(`ref ${f.ref} (${res.ok === false ? (res.reason ?? "failed") : "value mismatch"})`);
+      results.push({ ref: f.ref, ok: fieldOk, mismatch, ...detailsOf(f.ref, res) });
+    }
+    const text =
+      `Filled ${okCount}/${args.fields.length} fields` +
+      (issues.length > 0 ? `; issues: ${issues.join(", ")}` : "");
+    return ok({ text, details: { results } });
+  },
+});
+
+const SelectOptionArgs = Type.Object({
+  ref: Type.Integer({ description: "Element ref of a <select> from browser_snapshot ([ref=N])." }),
+  value: Type.Optional(Type.String({ description: "Option value attribute to select." })),
+  label: Type.Optional(Type.String({ description: "Visible option text/label to select (used if value is omitted)." })),
+});
+
+export const selectOptionTool = defineBrowserTool({
+  name: "browser_select_option",
+  label: "Browser Select Option",
+  description:
+    "Select an option in a native <select> dropdown by ref. Matches by option value, then by visible label/text, and fires change. Native selects cannot be driven by clicking coordinates — use this instead. Get the ref from browser_snapshot's [ref=N].",
+  promptSnippet: "Choose an option in a <select> dropdown by ref",
+  promptGuidelines: [
+    "Provide value (the option's value attribute) or label (the visible text). value wins if both given.",
+    "On no match, the result lists the available options so you can retry with a valid one.",
+    "Use this for native <select> elements — clicking coordinates does not work for OS dropdowns.",
+  ],
+  parameters: SelectOptionArgs,
+  async handler(args, { client }): Promise<Result<ToolOk, ToolErr>> {
+    if (args.value === undefined && args.label === undefined) {
+      return err({ kind: "invalid_state", message: "Provide value or label to select an option." });
+    }
+    const r = await resolveAndCall(client, args.ref, SELECT_FN, [args.value ?? null, args.label ?? null]);
+    if (!r.success) return r;
+    const res = r.data;
+    if (!res.ok) {
+      return err({ kind: "invalid_state", message: `Could not select option on ref ${args.ref}: ${res.reason ?? "unknown reason"}`, details: detailsOf(args.ref, res) });
+    }
+    return ok({
+      text: `Selected ${JSON.stringify(res.text)} (value=${JSON.stringify(res.value)}) on ref ${args.ref}`,
+      details: detailsOf(args.ref, res),
+    });
+  },
+});
+
+const SetCheckedArgs = Type.Object({
+  ref: Type.Integer({ description: "Element ref of a checkbox or radio from browser_snapshot ([ref=N])." }),
+  checked: Type.Boolean({ description: "Desired checked state." }),
+});
+
+export const setCheckedTool = defineBrowserTool({
+  name: "browser_set_checked",
+  label: "Browser Set Checked",
+  description:
+    "Set a checkbox or radio to a desired checked state by ref. Only acts if the current state differs, fires change, and reports the final state. Get the ref from browser_snapshot's [ref=N].",
+  promptSnippet: "Set a checkbox/radio checked state by ref",
+  promptGuidelines: [
+    "checked:true ticks the box, checked:false unticks it. Idempotent — no-op if already in the desired state.",
+    "For radios, set checked:true on the option you want; the group deselects the others.",
+  ],
+  parameters: SetCheckedArgs,
+  async handler(args, { client }): Promise<Result<ToolOk, ToolErr>> {
+    const r = await resolveAndCall(client, args.ref, CHECK_FN, [args.checked]);
+    if (!r.success) return r;
+    const res = r.data;
+    if (!res.ok) {
+      return err({ kind: "invalid_state", message: `Could not set checked on ref ${args.ref}: ${res.reason ?? "unknown reason"}`, details: detailsOf(args.ref, res) });
+    }
+    return ok({
+      text: `Set ref ${args.ref} checked=${res.checked}` + (res.changed === false ? " (already)" : ""),
+      details: detailsOf(args.ref, res),
+    });
+  },
+});
diff --git a/src/domains/isolated-tab.ts b/src/domains/isolated-tab.ts
index c759cec..73ed158 100644
--- a/src/domains/isolated-tab.ts
+++ b/src/domains/isolated-tab.ts
@@ -13,6 +13,7 @@
 import type { BrowserClient } from "../client";
 import { type Result, err, ok } from "../util/result";
 import { safeJs } from "../util/js-template";
+import { bindHarnessWindowId } from "../cdp/window-binding";
 import type { ToolErr } from "../util/tool";
 
 /** A tab attached by its own sessionId, ready to drive via callOnTarget. */
@@ -40,7 +41,10 @@ export const openIsolatedTab = async (client: BrowserClient): Promise<Result<Iso
   if (!created.success) return err(toToolErr(created.error.message));
   const { targetId } = created.data as { targetId: string };
 
-  if (createParams["newWindow"]) client.ownership().setHarnessWindow(targetId);
+  if (createParams["newWindow"]) {
+    client.ownership().setHarnessWindow(targetId);
+    await bindHarnessWindowId(client, targetId);
+  }
   client.ownership().add(targetId);
 
   const attached = await client.session().callBrowser("Target.attachToTarget", { targetId, flatten: true });
diff --git a/src/domains/navigate.ts b/src/domains/navigate.ts
index 4477485..e402efc 100644
--- a/src/domains/navigate.ts
+++ b/src/domains/navigate.ts
@@ -4,6 +4,7 @@ import { type Result, err, ok } from "../util/result";
 import { defineBrowserTool, type ToolErr, type ToolOk } from "../util/tool";
 import { applyTruncation } from "../util/truncate";
 import { safeJs } from "../util/js-template";
+import { bindHarnessWindowId } from "../cdp/window-binding";
 
 const NavigateArgs = Type.Object({
   url: Type.String({ description: "Full URL to navigate to (e.g. https://github.com)" }),
@@ -75,7 +76,7 @@ export const openUrlsTool = defineBrowserTool({
   description: "Open multiple URLs in parallel new tabs. Returns per-URL outcomes.",
   promptSnippet: "Open multiple URLs in new tabs (parallel)",
   promptGuidelines: [
-    "Use after web_search to open citations in parallel.",
+    "Use after browser_web_search to open citations in parallel.",
     "After opening, use browser_list_tabs / browser_switch_tab to navigate, then browser_snapshot to inspect each tab.",
     "Use browser_wait_for_load on a tab before extracting data from SPAs.",
   ],
@@ -83,17 +84,31 @@ export const openUrlsTool = defineBrowserTool({
   renderCall: (a) => new Text(`🌐 Opening ${a.urls.length} URL${a.urls.length !== 1 ? "s" : ""}…`, 0, 0),
   async handler(args, { client, onUpdate }): Promise<Result<ToolOk, ToolErr>> {
     const total = args.urls.length;
-    // Phase 1: create tabs in parallel.  Own them so they appear in
-    // browser_list_tabs scope:'owned' and group in the harness window.
-    const hw = client.ownership().harnessWindow();
-    const created = await Promise.all(args.urls.map(async (url): Promise<TabResult> => {
-      const params: Record<string, unknown> = { url: "about:blank" };
-      if (hw) params["openerId"] = hw;
-      else params["newWindow"] = true;
-      const r = await client.session().callBrowser("Target.createTarget", params);
+    // Phase 1: create tabs. All must land in ONE window. If the harness window
+    // already exists, open every url as its child in parallel. If it doesn't
+    // (fresh/closed), create the FIRST url as a new dedicated window (binding
+    // its windowId) and open the rest as children of it — a parallel
+    // newWindow:true per url would otherwise scatter tabs across N windows.
+    let seed = client.ownership().harnessWindow();
+    let seedResult: TabResult | undefined;
+    if (!seed) {
+      const url0 = args.urls[0];
+      if (url0 === undefined) return err({ kind: "invalid_state", message: "no URLs provided" });
+      const r0 = await client.session().callBrowser("Target.createTarget", { url: "about:blank", newWindow: true });
+      if (!r0.success) return err({ kind: "cdp_error", message: r0.error.message });
+      seed = (r0.data as { targetId: string }).targetId;
+      client.ownership().setHarnessWindow(seed);
+      await bindHarnessWindowId(client, seed);
+      client.ownership().add(seed);
+      seedResult = { url: url0, targetId: seed, ok: true };
+    }
+    const seededWindow = seed;
+    const created = await Promise.all(args.urls.map(async (url, i): Promise<TabResult> => {
+      // Reuse the seed tab (created above) for the first url instead of duplicating it.
+      if (i === 0 && seedResult) return seedResult;
+      const r = await client.session().callBrowser("Target.createTarget", { url: "about:blank", openerId: seededWindow });
       if (!r.success) return { url, targetId: "", ok: false, error: r.error.message };
       const c = r.data as { targetId: string };
-      if (params["newWindow"]) client.ownership().setHarnessWindow(c.targetId);
       client.ownership().add(c.targetId);
       return { url, targetId: c.targetId, ok: true };
     }));