diff --git a/.claude/settings.json b/.claude/settings.json
index fbdc243f..1b61758d 100644
--- a/.claude/settings.json
+++ b/.claude/settings.json
@@ -44,7 +44,18 @@
       "WebFetch(domain:docs.litellm.ai)",
       "Bash(cat /home/timothy/aden/hive/.venv/lib/python3.11/site-packages/litellm-*.dist-info/METADATA)",
       "Bash(find \"/home/timothy/.hive/agents/queens/queen_brand_design/sessions/session_20260415_100751_d49f4c28/\" -type f -name \"*.json*\" -exec grep -l \"协日\" {} \\\\;)",
-      "Bash(grep -v ':0$')"
+      "Bash(grep -v ':0$')",
+      "Bash(curl -s -m 2 http://127.0.0.1:4002/sse -o /dev/null -w 'status=%{http_code} time=%{time_total}s\\\\n')",
+      "mcp__gcu-tools__browser_status",
+      "mcp__gcu-tools__browser_start",
+      "mcp__gcu-tools__browser_navigate",
+      "mcp__gcu-tools__browser_evaluate",
+      "mcp__gcu-tools__browser_screenshot",
+      "mcp__gcu-tools__browser_open",
+      "mcp__gcu-tools__browser_click_coordinate",
+      "mcp__gcu-tools__browser_get_rect",
+      "mcp__gcu-tools__browser_type_focused",
+      "mcp__gcu-tools__browser_wait"
     ],
     "additionalDirectories": [
       "/home/timothy/.hive/skills/writing-hive-skills",
diff --git a/.mcp.json b/.mcp.json
index da39e4ff..b37e500c 100644
--- a/.mcp.json
+++ b/.mcp.json
@@ -1,3 +1,10 @@
 {
-  "mcpServers": {}
+  "mcpServers": {
+    "gcu-tools": {
+      "type": "stdio",
+      "command": "uv",
+      "args": ["run", "python", "-m", "gcu.server", "--stdio"],
+      "cwd": "/home/timothy/aden/hive/tools"
+    }
+  }
 }
diff --git a/core/framework/agents/queen/reference/gcu_guide.md b/core/framework/agents/queen/reference/gcu_guide.md
index e0b8bd1d..2922f58e 100644
--- a/core/framework/agents/queen/reference/gcu_guide.md
+++ b/core/framework/agents/queen/reference/gcu_guide.md
@@ -25,7 +25,6 @@ All tools are prefixed with `browser_`:
 - `browser_screenshot` — visual capture (annotated PNG)
 <!-- /vision-only -->
 - `browser_shadow_query`, `browser_get_rect` — locate elements (shadow-piercing via `>>>`)
-- `browser_coords` — convert image pixels to CSS pixels (always use `css_x/y`, never `physical_x/y`)
 - `browser_scroll`, `browser_wait` — navigation helpers
 - `browser_evaluate` — run JavaScript
 - `browser_close`, `browser_close_finished` — tab cleanup
@@ -38,9 +37,9 @@ All tools are prefixed with `browser_`:
 
 Neither tool is "preferred" universally — they're for different jobs. Default to snapshot on text-heavy static pages, screenshot on SPAs and anything shadow-DOM-heavy. Activate the `browser-automation` skill for the full decision tree.
 
-## Coordinate rule: always CSS pixels
+## Coordinate rule
 
-Chrome DevTools Protocol `Input.dispatchMouseEvent` takes **CSS pixels**, not physical pixels. After a screenshot, use `browser_coords(image_x, image_y)` and feed the returned `css_x/y` (NOT `physical_x/y`) to `browser_click_coordinate`, `browser_hover_coordinate`, `browser_press_at`. Feeding physical pixels on a HiDPI display (DPR=1.6, 2, or 3) overshoots by `DPR×` and clicks land in the wrong place. `getBoundingClientRect()` already returns CSS pixels — pass through unchanged, no DPR multiplication.
+Every browser tool that takes or returns coordinates operates in **fractions of the viewport (0..1 for both axes)**. Read a target's proportional position off `browser_screenshot` ("~35% from the left, ~20% from the top" → `(0.35, 0.20)`) and pass that to `browser_click_coordinate` / `browser_hover_coordinate` / `browser_press_at`. `browser_get_rect` and `browser_shadow_query` return `rect.cx` / `rect.cy` as fractions. The tools multiply by `cssWidth` / `cssHeight` internally — no scale awareness required. Fractions are used because every vision model (Claude, GPT-4o, Gemini, local VLMs) resizes/tiles images differently; proportions are invariant. Avoid raw `getBoundingClientRect()` via `browser_evaluate` for coord lookup; use `browser_get_rect` instead.
 
 ## System prompt tips for browser nodes
 
diff --git a/core/framework/orchestrator/gcu.py b/core/framework/orchestrator/gcu.py
index 43ce1fff..1ac459cc 100644
--- a/core/framework/orchestrator/gcu.py
+++ b/core/framework/orchestrator/gcu.py
@@ -42,25 +42,26 @@ after an interaction unless you need a fresh view.
 Only fall back to `browser_get_text` for extracting small elements by
 CSS selector.
 
-## Coordinates: always CSS pixels
+## Coordinates
 
-Chrome DevTools Protocol `Input.dispatchMouseEvent` takes **CSS
-pixels**, not physical pixels. This is critical and often gets wrong:
+Every browser tool that takes or returns coordinates operates in
+**fractions of the viewport (0..1 for both axes)**. Read a target's
+proportional position off `browser_screenshot` — "this button is
+~35% from the left, ~20% from the top" → pass `(0.35, 0.20)`.
+`browser_get_rect` and `browser_shadow_query` return `rect.cx` /
+`rect.cy` as fractions in the same space. The tools handle the
+fraction → CSS-px multiplication internally; you do not need to
+track image pixels, DPR, or any scale factor.
 
-| Tool | Unit |
-|---|---|
-| `browser_click_coordinate(x, y)` | **CSS pixels** |
-| `browser_hover_coordinate(x, y)` | **CSS pixels** |
-| `browser_press_at(x, y, key)` | **CSS pixels** |
-| `getBoundingClientRect()` | already CSS pixels — pass straight through |
-| `browser_coords(img_x, img_y)` | returns `css_x/y` (use this) and `physical_x/y` (debug only) |
+Why fractions: every vision model (Claude, GPT-4o, Gemini, local
+VLMs) resizes or tiles images differently before the model sees the
+pixels. Proportions survive every such transform; pixel coordinates
+only "work" per-model and break when you swap backends.
 
-**Always use `css_x/y`** from `browser_coords`. Feeding `physical_x/y`
-on a HiDPI display overshoots by `DPR×` — clicks land DPR times too
-far right and down. On a DPR=1.6 display that's 60% off.
-
-Never multiply `getBoundingClientRect()` by `devicePixelRatio` — it's
-already in the right unit.
+Avoid raw `browser_evaluate` + `getBoundingClientRect()` for coord
+lookup — that returns CSS px and will be wrong when fed to click
+tools. Prefer `browser_get_rect` / `browser_shadow_query`, which
+return fractions.
 
 ## Rich-text editors (X, LinkedIn DMs, Gmail, Reddit, Slack, Discord)
 
@@ -88,11 +89,10 @@ reach shadow elements transparently.
 
 **Shadow-heavy site workflow:**
 1. `browser_screenshot()` → visual image
-2. Identify target visually → image coordinate
-3. `browser_coords(x, y)` → CSS px
-4. `browser_click_coordinate(css_x, css_y)` → lands via native hit
-   test; inputs get focused regardless of shadow depth
-5. Type via `browser_type_focused` (no selector needed — types into the
+2. Identify target visually → pixel `(x, y)` read straight off the image
+3. `browser_click_coordinate(x, y)` → lands via native hit test;
+   inputs get focused regardless of shadow depth
+4. Type via `browser_type_focused` (no selector needed — types into the
    already-focused element), or `browser_type` if you have a selector
 
 For selector-style access when you know the shadow path:
diff --git a/core/framework/skills/_default_skills/browser-automation/SKILL.md b/core/framework/skills/_default_skills/browser-automation/SKILL.md
index 0a0e7d7d..311ac1d9 100644
--- a/core/framework/skills/_default_skills/browser-automation/SKILL.md
+++ b/core/framework/skills/_default_skills/browser-automation/SKILL.md
@@ -12,25 +12,22 @@ metadata:
 
 All GCU browser tools drive a real Chrome instance through the Beeline extension and Chrome DevTools Protocol (CDP). That means clicks, keystrokes, and screenshots are processed by the actual browser's native hit testing, focus, and layout engines — **not** a synthetic event layer. Understanding this unlocks strategies that make hard sites easy.
 
-## Coordinates: always CSS pixels
+## Coordinates
 
-**Chrome DevTools Protocol `Input.dispatchMouseEvent` operates in CSS pixels, not physical pixels.**
-
-When you call `browser_coords(image_x, image_y)` after a screenshot, the returned dict has both `css_x/y` and `physical_x/y`. **Always use `css_x/y` for clicks, hovers, and key presses.**
+Every browser tool that takes or returns coordinates operates in **fractions of the viewport (0..1 for both axes)**. Read a target's proportional position off `browser_screenshot` — "this button is about 35% from the left and 20% from the top" → pass `(0.35, 0.20)`. Rect-returning tools (`browser_get_rect`, `browser_shadow_query`, and the `rect` inside `focused_element`) also return fractions. The tools convert to CSS pixels internally before dispatching to Chrome.
 
 ```
-browser_screenshot()          → image (downscaled to 800/900 px wide)
-browser_coords(img_x, img_y)  → {css_x, css_y, physical_x, physical_y}
-browser_click_coordinate(css_x, css_y)   ← USE css_x/y
-browser_hover_coordinate(css_x, css_y)   ← USE css_x/y
-browser_press_at(css_x, css_y, key)      ← USE css_x/y
+browser_screenshot()                  → image + cssWidth/cssHeight in meta
+browser_click_coordinate(x, y)        → x, y are fractions 0..1
+browser_hover_coordinate(x, y)        → fractions
+browser_press_at(x, y, key)           → fractions
+browser_get_rect(selector) → rect     → rect.cx / rect.cy are fractions
+browser_shadow_query(...)  → rect     → same
 ```
 
-Feeding `physical_x/y` on a HiDPI display overshoots by DPR× — on a DPR=1.6 laptop, clicks land 60% too far right and down. The ratio between `physicalScale` and `cssScale` tells you the effective DPR.
+**Why fractions:** every vision model (Claude ~1.15 MP target, GPT-4o 512-px tiles, Gemini, local VLMs) resizes or tiles images differently before the model sees the pixels. Proportions survive every such transform; pixel coordinates only "work" per-model and silently break when you swap backends. Four-decimal precision (`0.0001` ≈ 0.17 CSS px on a 1717-wide viewport) is more than enough for the tightest targets.
 
-`getBoundingClientRect()` already returns CSS pixels — feed those values straight through to click/hover tools without any DPR multiplication.
-
-**Exception for zoomed elements:** pages that use `zoom` or `transform: scale()` on a container (LinkedIn's `#interop-outlet`, some embedded iframes) render in a scaled local coordinate space. `getBoundingClientRect` there may not match CDP's hit space. Use `browser_shadow_query` which handles the math, or fall back to visually picking coordinates from a screenshot.
+**Exception for zoomed elements:** pages that use `zoom` or `transform: scale()` on a container (LinkedIn's `#interop-outlet`, some embedded iframes) render in a scaled local coordinate space. `getBoundingClientRect` there may not match CDP's hit space. Prefer `browser_shadow_query` (which handles the math and returns fractions) or visually pick coordinates from a screenshot. Avoid raw `browser_evaluate` + `getBoundingClientRect()` for coord lookup — that returns CSS px and will be wrong when fed to click tools.
 
 ## Screenshot + coordinates is shadow-agnostic — prefer it on shadow-heavy sites
 
@@ -38,7 +35,7 @@ On sites that use Shadow DOM heavily (Reddit's faceplate Web Components, LinkedI
 
 Why:
 
-- **CDP hit testing walks shadow roots natively.** `browser_click_coordinate(css_x, css_y)` routes through Chrome's native hit tester, which traverses open shadow roots automatically. You don't need to know the shadow structure.
+- **CDP hit testing walks shadow roots natively.** `browser_click_coordinate(x, y)` routes through Chrome's native hit tester, which traverses open shadow roots automatically. You don't need to know the shadow structure.
 - **Keyboard dispatch follows focus** into shadow roots. After a click focuses an input (even one three shadow levels deep), `browser_press(...)` with no selector dispatches keys to `document.activeElement`'s computed focus target.
 - **Screenshots render the real layout** regardless of DOM implementation.
 
@@ -46,12 +43,11 @@ Whereas `wait_for_selector`, `browser_click(selector=...)`, `browser_type(select
 
 ### Recommended workflow on shadow-heavy sites
 
-1. `browser_screenshot()` → visual image
-2. Identify the target visually → image pixel `(x, y)` (eyeball from the screenshot)
-3. `browser_coords(x, y)` → convert to CSS px
-4. `browser_click_coordinate(css_x, css_y)` → lands on the element via native hit testing; inputs get focused. **The response now includes `focused_element: {tag, id, role, contenteditable, rect, ...}`** — use it to verify you actually focused what you intended.
-5. `browser_type_focused(text="...")` → dispatches CDP `Input.insertText` to `document.activeElement`. Shadow roots, iframes, Lexical, Draft.js, ProseMirror all just work. Use `browser_type(selector, text)` instead when you have a reliable CSS selector for a light-DOM element.
-6. Verify via `browser_screenshot` OR `browser_get_attribute` on a known-reachable marker (e.g. check that the Send button's `aria-disabled` flipped to `false`).
+1. `browser_screenshot()` → JPEG; meta includes `cssWidth`/`cssHeight` for reference.
+2. Identify the target visually → estimate its proportional position `(fx, fy)` where each is in `0..1`.
+3. `browser_click_coordinate(fx, fy)` → tool converts to CSS px and dispatches; CDP native hit testing focuses the element. **The response includes `focused_element: {tag, id, role, contenteditable, rect, inFrame?, ...}`** — use it to verify you actually focused what you intended. `rect` is in fractions (same space as your input). When focus is inside a same-origin iframe, the descriptor reports the inner element and adds `inFrame: [...]` breadcrumbs.
+4. `browser_type_focused(text="...")` → inserts text into `document.activeElement` (traverses into same-origin iframes automatically). Shadow roots, iframes, Lexical, Draft.js, ProseMirror all just work. Use `browser_type(selector, text)` instead when you have a reliable CSS selector for a light-DOM element.
+5. Verify via `browser_screenshot` OR `browser_get_attribute` on a known-reachable marker (e.g. check that the Send button's `aria-disabled` flipped to `false`).
 
 ### The click→type loop (canonical pattern)
 
@@ -80,7 +76,7 @@ browser_shadow_query("reddit-search-large >>> #search-input")
 browser_get_rect("#interop-outlet >>> #ember37 >>> p")
 ```
 
-Returns the element's rect in **CSS pixels** (feed directly to click tools). Remember: `browser_type` and `wait_for_selector` do **not** support `>>>` — only shadow_query and get_rect do.
+Returns the element's rect as **fractions of the viewport** (feed `rect.cx` / `rect.cy` directly to click tools). Remember: `browser_type` and `wait_for_selector` do **not** support `>>>` — only shadow_query and get_rect do.
 
 ## Navigation and waiting
 
@@ -220,25 +216,15 @@ Recognized without modifiers: `Enter`, `Tab`, `Escape`, `Backspace`, `Delete`, `
 ## Screenshots
 
 ```
-browser_screenshot()                    # viewport, 900 px wide by default
-browser_screenshot(full_page=True)      # full scrollable page
+browser_screenshot()                    # viewport, 800 px wide JPEG
+browser_screenshot(full_page=True)      # full scrollable page (overview only — don't click off a full-page shot)
 browser_screenshot(selector="#header")  # clip to element's rect
 ```
 
-Returns a PNG with automatic downscaling to a target width (default 900 px) plus a JSON metadata block containing `cssWidth`, `devicePixelRatio`, `physicalScale`, `cssScale`, and a `scaleHint` string. The image is also annotated with a highlight rectangle/dot showing the last interaction (click, hover, type) if one happened on this tab.
+Returns a JPEG (quality 75, ~50–120 KB) at 800 px wide. The pixel width is purely a bandwidth choice; all tool coordinates are fractions of the viewport and are invariant to image size. Metadata includes `imageWidth` (800), `cssWidth`, `cssHeight` (for reference), and `physicalScale`. The image is annotated with a highlight rectangle/dot showing the last interaction (click, hover, type) if one happened on this tab.
 
 The highlight overlay stays visible on the page for **10 seconds** after each interaction, then fades. Before a screenshot is likely, make sure your click / hover / type happens <10 s before the screenshot.
 
-### Anatomy of the scale fields
-
-- `cssWidth` = `window.innerWidth` (CSS px)
-- `devicePixelRatio` = `window.devicePixelRatio` (often 1.6, 2, or 3 on modern displays)
-- `physicalScale = png_width / image_width` (how many physical-px per image-px)
-- `cssScale = cssWidth / image_width` (how many CSS-px per image-px)
-- Effective DPR = `physicalScale / cssScale` (should match `devicePixelRatio`)
-
-When converting image coordinates for clicks, always use `cssScale`. The `physicalScale` field is there for debugging HiDPI displays, not for inputs.
-
 ## Scrolling
 
 - Use large scroll amounts (~2000) when loading more content — sites like Twitter and LinkedIn have lazy loading for paging.
@@ -363,7 +349,8 @@ Then pass the most specific selector that uniquely identifies the right input (e
 - **Typing into a rich-text editor without clicking first → send button stays disabled.** Draft.js (X), Lexical (Gmail, LinkedIn DMs), ProseMirror (Reddit), and React-controlled `contenteditable` elements only register input as "real" when the element received a native focus event — JS-sourced `.focus()` is not enough. `browser_type` now does this automatically via a real CDP pointer click before inserting text, but always verify the submit button's `disabled` state before clicking send. See the "ALWAYS click before typing" section above.
 - **Using per-character `keyDown` on Lexical / Draft.js editors → keys dispatch but text never appears.** Those editors intercept `beforeinput` and route insertion through their own state machine; raw keyDown events are silently dropped. `browser_type` now uses `Input.insertText` by default (the CDP IME-commit method) which these editors accept cleanly. Only set `use_insert_text=False` when you explicitly need per-keystroke dispatch.
 - **Leaving a composer with text then trying to navigate → `beforeunload` dialog hangs the bridge.** LinkedIn and several other sites pop a native "unsent message" confirm. `browser_navigate` and `close_tab` both time out against this. Always strip `window.onbeforeunload = null` via `browser_evaluate` before any navigation after typing in a composer, or wrap your logic in a `try/finally` that runs the cleanup block.
-- **Clicking at physical pixels.** CDP uses CSS px. `browser_coords` returns both for debugging, but always feed `css_x/y` to click tools.
+- **Click landed in the wrong region (sidebar / header instead of target).** Check `focused_element` in the click response — it's ground truth for what actually got focused, including the `inFrame` breadcrumb when focus ends up inside a same-origin iframe. If it isn't the target (e.g. `className: "msg-conversation-listitem__link"` when you meant to hit a composer), adjust the fraction and retry. Coordinates you pass are fractions of the viewport; the tool multiplies by `cssWidth` / `cssHeight` internally, so a wrong result means your estimated proportion was off — not that any scale went sideways.
+- **Accidentally passing pixels to click / hover / press_at.** The tools reject any coord outside `[-0.1, 1.5]` with a clear error. If you see that error, you passed a pixel (like 815) instead of a fraction (like 0.475). Use `browser_get_rect` to get exact fractional cx/cy, or read proportions off `browser_screenshot`.
 - **Calling `wait_for_selector` on a shadow element.** It'll always time out. Use `browser_shadow_query` or the screenshot + coordinate strategy.
 - **Relying on `innerHTML` in injected scripts on LinkedIn.** Silently discarded. Use `createElement` + `appendChild`.
 - **Not waiting for SPA hydration.** `wait_until="load"` fires before React/Vue rendering on many sites. Add a 2–3 s sleep before querying for chrome elements.
diff --git a/core/framework/skills/_default_skills/linkedin-automation/SKILL.md b/core/framework/skills/_default_skills/linkedin-automation/SKILL.md
index 844a904b..9ced68a4 100644
--- a/core/framework/skills/_default_skills/linkedin-automation/SKILL.md
+++ b/core/framework/skills/_default_skills/linkedin-automation/SKILL.md
@@ -34,7 +34,7 @@ LinkedIn is the hardest mainstream site to automate because it combines **shadow
 | Pending connection card | `.invitation-card, .invitations-card, [data-test-incoming-invitation-card]` | Filter out "invited you to follow" / "subscribe" cards |
 | Accept button | `button[aria-label*="Accept"]` within the card scope | Per-card scoping is critical — there are many Accept buttons on the page |
 
-LinkedIn changes class names aggressively. If a class-based selector breaks, fall back to **`browser_screenshot` → visual identification → `browser_coords` → `browser_click_coordinate`**. The screenshot + coord path works regardless of class-name churn and regardless of shadow DOM.
+LinkedIn changes class names aggressively. If a class-based selector breaks, fall back to **`browser_screenshot` → visual identification → `browser_click_coordinate`** with the pixel you read straight off the image (screenshots are CSS-sized, no conversion). The screenshot + coord path works regardless of class-name churn and regardless of shadow DOM.
 
 ## Profile Message flow (verified end-to-end 2026-04-11)
 
diff --git a/tools/src/gcu/browser/bridge.py b/tools/src/gcu/browser/bridge.py
index 52f25056..472e86a1 100644
--- a/tools/src/gcu/browser/bridge.py
+++ b/tools/src/gcu/browser/bridge.py
@@ -93,33 +93,57 @@ def clear_tab_highlights(tab_ids) -> None:
         _interaction_highlights.pop(tid, None)
 
 
-# Compact descriptor of document.activeElement. Returned by both click()
+# Compact descriptor of the focused element. Returned by both click()
 # and click_coordinate() so the agent can verify it focused what it
-# intended, then decide whether to follow up with browser_type_focused(text=...).
-# Keeping this as a single shared string avoids drift
-# between the two click paths.
+# intended. When the outer document's activeElement is an <iframe>,
+# we recurse into the iframe's document (same-origin only) so the
+# response describes the real inner element — otherwise the agent
+# always sees {tag: "iframe"} and can't tell whether it hit the
+# composer or something else inside the frame (e.g. a sidebar item
+# in LinkedIn's #interop-outlet messaging overlay).
 _FOCUSED_ELEMENT_JS = """
 (function() {
+    function describe(el) {
+        var rect = el.getBoundingClientRect();
+        var attrs = {};
+        for (var i = 0; i < el.attributes.length && i < 10; i++) {
+            attrs[el.attributes[i].name] = el.attributes[i].value.substring(0, 200);
+        }
+        return {
+            tag: el.tagName.toLowerCase(),
+            id: el.id || null,
+            className: el.className || null,
+            name: el.getAttribute('name') || null,
+            type: el.getAttribute('type') || null,
+            role: el.getAttribute('role') || null,
+            contenteditable: el.getAttribute('contenteditable') || null,
+            text: (el.innerText || '').substring(0, 200),
+            value: (el.value !== undefined ? String(el.value).substring(0, 200) : null),
+            attributes: attrs,
+            rect: { x: rect.x, y: rect.y, width: rect.width, height: rect.height }
+        };
+    }
     var el = document.activeElement;
     if (!el || el === document.body) return null;
-    var rect = el.getBoundingClientRect();
-    var attrs = {};
-    for (var i = 0; i < el.attributes.length && i < 10; i++) {
-        attrs[el.attributes[i].name] = el.attributes[i].value.substring(0, 200);
+    // Descend into same-origin iframes. Capped at 5 levels of
+    // nesting to bound cost. Cross-origin frames throw on
+    // contentDocument access → we catch and report the outermost
+    // iframe instead.
+    var framePath = [];
+    var depth = 0;
+    while (el && (el.tagName === 'IFRAME' || el.tagName === 'FRAME') && depth < 5) {
+        framePath.push(el.id || el.getAttribute('data-testid') || el.tagName.toLowerCase());
+        var innerDoc = null;
+        try { innerDoc = el.contentDocument; } catch (e) { innerDoc = null; }
+        if (!innerDoc) break;
+        var innerActive = innerDoc.activeElement;
+        if (!innerActive || innerActive === innerDoc.body) break;
+        el = innerActive;
+        depth++;
     }
-    return {
-        tag: el.tagName.toLowerCase(),
-        id: el.id || null,
-        className: el.className || null,
-        name: el.getAttribute('name') || null,
-        type: el.getAttribute('type') || null,
-        role: el.getAttribute('role') || null,
-        contenteditable: el.getAttribute('contenteditable') || null,
-        text: (el.innerText || '').substring(0, 200),
-        value: (el.value !== undefined ? String(el.value).substring(0, 200) : null),
-        attributes: attrs,
-        rect: { x: rect.x, y: rect.y, width: rect.width, height: rect.height }
-    };
+    var out = describe(el);
+    if (framePath.length) out.inFrame = framePath;
+    return out;
 })()
 """
 
@@ -477,9 +501,9 @@ class BeelineBridge:
         """Close a tab by ID."""
         result = await self._send("tab.close", tabId=tab_id)
         # Drop per-tab state — the id may be reused by Chrome much
-        # later, and carrying a stale highlight, scale, or "attached"
-        # flag forward would misannotate screenshots, misalign click
-        # coordinates, or skip a needed reattach on the reused id.
+        # later, and carrying a stale highlight or "attached" flag
+        # forward would misannotate screenshots or skip a needed
+        # reattach on the reused id.
         self._cdp_attached.discard(tab_id)
         _interaction_highlights.pop(tab_id, None)
         from .tools.inspection import clear_tab_state
@@ -953,16 +977,36 @@ class BeelineBridge:
     async def _read_focused_element(self, tab_id: int) -> dict | None:
         """Read document.activeElement and return a compact descriptor.
 
-        Returns None on any failure — never raises. Used by both click
-        paths (selector-based click() and click_coordinate()) so the
-        agent gets the same response shape regardless of which one was
-        called. The descriptor lets the agent answer "did my click land
-        on an editable?" without a second round-trip.
+        The JS returns ``rect`` fields in CSS px (they come straight
+        from ``getBoundingClientRect``). We convert them to fractions
+        of the viewport here so the agent sees a rect in the same
+        coord space it passed to click / hover / press_at.
+
+        Returns None on any failure — never raises.
         """
         try:
             await self._try_enable_domain(tab_id, "Runtime")
             result = await self.evaluate(tab_id, _FOCUSED_ELEMENT_JS)
-            return (result or {}).get("result")
+            info = (result or {}).get("result")
+            if info and isinstance(info, dict) and isinstance(info.get("rect"), dict):
+                from .tools.inspection import _viewport_sizes
+
+                vp = _viewport_sizes.get(tab_id)
+                if vp and vp[0] > 0 and vp[1] > 0:
+                    cw, ch = float(vp[0]), float(vp[1])
+                    r = info["rect"]
+                    info["rect"] = {
+                        "x": round(r.get("x", 0) / cw, 4),
+                        "y": round(r.get("y", 0) / ch, 4),
+                        "width": round(r.get("width", 0) / cw, 4),
+                        "height": round(r.get("height", 0) / ch, 4),
+                    }
+                else:
+                    # Degraded: cache missing (no screenshot taken
+                    # yet). Leave rect in CSS px and flag it so the
+                    # agent can tell.
+                    info["rectSpace"] = "css"
+            return info
         except Exception:
             return None
 
@@ -975,18 +1019,11 @@ class BeelineBridge:
         button_map = {"left": "left", "right": "right", "middle": "middle"}
         cdp_button = button_map.get(button, "left")
 
-        from .tools.inspection import _screenshot_css_scales, _screenshot_scales
-
-        phys_scale = _screenshot_scales.get(tab_id, "unset")
-        css_scale = _screenshot_css_scales.get(tab_id, "unset")
         logger.info(
-            "click_coordinate tab=%d: x=%.1f, y=%.1f → CDP Input.dispatchMouseEvent. "
-            "stored_scales: physicalScale=%s, cssScale=%s",
+            "click_coordinate tab=%d: x=%.1f, y=%.1f → CDP Input.dispatchMouseEvent",
             tab_id,
             x,
             y,
-            phys_scale,
-            css_scale,
         )
 
         await self._cdp(
diff --git a/tools/src/gcu/browser/tools/advanced.py b/tools/src/gcu/browser/tools/advanced.py
index 2b929804..b825ec1b 100644
--- a/tools/src/gcu/browser/tools/advanced.py
+++ b/tools/src/gcu/browser/tools/advanced.py
@@ -255,6 +255,17 @@ def register_advanced_tools(mcp: FastMCP) -> None:
 
         try:
             result = await bridge.resize(target_tab, width, height)
+            # Invalidate per-tab scale caches — CSS width changed, so the
+            # cached viewport dimensions are stale. Click / rect tools
+            # will re-query innerWidth / innerHeight on next use via
+            # _ensure_viewport_size.
+            try:
+                from .inspection import _screenshot_scales, _viewport_sizes
+
+                _viewport_sizes.pop(target_tab, None)
+                _screenshot_scales.pop(target_tab, None)
+            except Exception:
+                pass
             return result
         except Exception as e:
             return {"ok": False, "error": str(e)}
diff --git a/tools/src/gcu/browser/tools/inspection.py b/tools/src/gcu/browser/tools/inspection.py
index 51186f9b..a4f4c08e 100644
--- a/tools/src/gcu/browser/tools/inspection.py
+++ b/tools/src/gcu/browser/tools/inspection.py
@@ -23,13 +23,26 @@ from .tabs import _get_context
 
 logger = logging.getLogger(__name__)
 
-# Target width for normalized screenshots (px in the delivered image)
-_SCREENSHOT_WIDTH = 600
 
-# Maps tab_id -> physical scale: image_coord × scale = physical pixels (for CDP Input events)
+# Fixed output width for all screenshots (bandwidth default). This
+# number does NOT affect coordinate semantics — click / hover / press
+# and rect tools all work in fractions of the viewport (0..1), which
+# are invariant to whatever resize / tile the vision API applies. The
+# 800 px width is simply small enough to keep JPEG payloads under
+# ~150 KB on typical UI screenshots.
+_SCREENSHOT_WIDTH = 800
+
+# Per-tab viewport-size cache populated on every browser_screenshot
+# and on lazy-init inside the click tools. Stores CSS-pixel viewport
+# dimensions (window.innerWidth / window.innerHeight). Click tools
+# multiply fractional inputs by these to get CSS coords before
+# dispatching CDP events; rect tools divide CSS-pixel DOM rects by
+# these to produce fractions for the agent.
+_viewport_sizes: dict[int, tuple[int, int]] = {}
+
+# Optional debug cache — physical-px scale per tab (orig_png_w /
+# _SCREENSHOT_WIDTH). Logged only; no consumer.
 _screenshot_scales: dict[int, float] = {}
-# Maps tab_id -> CSS scale: image_coord × scale = CSS pixels (for DOM APIs / getBoundingClientRect)
-_screenshot_css_scales: dict[int, float] = {}
 
 
 def clear_tab_state(tab_ids) -> None:
@@ -51,18 +64,25 @@ def _resize_and_annotate(
     css_width: int,
     dpr: float = 1.0,
     highlights: list[dict] | None = None,
-    width: int = _SCREENSHOT_WIDTH,
-) -> tuple[str, float, float]:
-    """Resize a base64 PNG to _SCREENSHOT_WIDTH wide, annotate highlights.
+) -> tuple[str, float]:
+    """Resize the captured PNG down to ``_SCREENSHOT_WIDTH`` (=800 px)
+    and re-encode as JPEG quality 75.
 
-    Returns (new_b64, physical_scale, css_scale) where:
-      physical_scale = physical_px_per_image_px  (multiply image coords → physical px)
-      css_scale      = css_px_per_image_px        (multiply image coords → CSS px for DOM APIs)
+    The image dimensions do NOT determine click coordinates any more —
+    the tools work in viewport fractions. This helper exists purely
+    for bandwidth + annotation overlay. Returns ``(new_b64,
+    physical_scale)`` where ``physical_scale = orig_png_w / output_w``
+    is kept for debug logging.
 
-    Highlights have x,y,w,h in CSS pixels (what getBoundingClientRect returns,
-    and what CDP Input.dispatchMouseEvent accepts).
-    Falls back to original data if Pillow unavailable or resize fails.
+    Highlight rects arrive in CSS px; they're converted to image-space
+    for overlay drawing via the local ``css_to_image = css_width /
+    output_w`` factor (computed inline — no external cache).
     """
+    if not css_width or css_width <= 0:
+        # Bridge always supplies css_width from window.innerWidth; only
+        # reach here on a degraded response. Return the raw PNG.
+        return data, 1.0
+
     try:
         from PIL import Image, ImageDraw, ImageFont
     except ImportError:
@@ -72,48 +92,44 @@ def _resize_and_annotate(
             import struct
 
             orig_w = struct.unpack(">I", raw[16:20])[0]
-        raw_size_bytes = len(raw)
-        physical_scale = orig_w / width if orig_w and width else 1.0
-        css_scale = (css_width / width) if css_width else (physical_scale / max(dpr, 1.0))
+        physical_scale = orig_w / _SCREENSHOT_WIDTH if orig_w else 1.0
         logger.warning(
-            "PIL not available — screenshot resize SKIPPED (cannot downscale image). "
-            "raw_size=%d bytes, png_width=%d, css_width=%s, dpr=%s, target_width=%d. "
-            "Returning ORIGINAL image with computed scales: physicalScale=%.4f, cssScale=%.4f. "
-            "Agent must use browser_coords() to convert image positions before clicking.",
-            raw_size_bytes,
-            orig_w,
+            "PIL not available — screenshot resize SKIPPED. "
+            "Returning raw physical-px PNG. physicalScale=%.4f, "
+            "css_width=%d, dpr=%s. Install Pillow for annotation.",
+            physical_scale,
             css_width,
             dpr,
-            width,
-            physical_scale,
-            css_scale,
         )
-        return data, round(physical_scale, 4), round(css_scale, 4)
+        return data, round(physical_scale, 4)
 
     try:
         raw = base64.b64decode(data)
         img = Image.open(io.BytesIO(raw)).convert("RGBA")
         orig_w, orig_h = img.size
 
-        physical_scale = orig_w / width
-        css_scale = (css_width / width) if css_width else (physical_scale / max(dpr, 1.0))
+        physical_scale = orig_w / _SCREENSHOT_WIDTH
+        new_w = _SCREENSHOT_WIDTH
+        new_h = round(orig_h * new_w / orig_w)
+        if (new_w, new_h) != img.size:
+            img = img.resize((new_w, new_h), Image.LANCZOS)
+
+        # Local CSS → image px factor for overlay draws. Kept local —
+        # not exported, not stored, not leaked to the agent.
+        css_to_image = css_width / _SCREENSHOT_WIDTH
 
         logger.info(
-            "Screenshot resize: orig=%dx%d → target=%dx%d, css_width=%s, dpr=%s, physicalScale=%.4f, cssScale=%.4f",
+            "Screenshot: orig=%dx%d → out=%dx%d (css_width=%d, dpr=%s), physicalScale=%.4f, css_to_image=%.4f",
             orig_w,
             orig_h,
-            width,
-            round(orig_h * width / orig_w),
+            new_w,
+            new_h,
             css_width,
             dpr,
             physical_scale,
-            css_scale,
+            css_to_image,
         )
 
-        new_w = width
-        new_h = round(orig_h * new_w / orig_w)
-        img = img.resize((new_w, new_h), Image.LANCZOS)
-
         if highlights:
             overlay = Image.new("RGBA", img.size, (0, 0, 0, 0))
             draw = ImageDraw.Draw(overlay)
@@ -125,11 +141,11 @@ def _resize_and_annotate(
             for h in highlights:
                 kind = h.get("kind", "rect")
                 label = h.get("label", "")
-                # Highlights are in CSS px → convert to image px
-                ix = h["x"] / css_scale
-                iy = h["y"] / css_scale
-                iw = h.get("w", 0) / css_scale
-                ih = h.get("h", 0) / css_scale
+                # Highlights arrive in CSS px → convert to image px.
+                ix = h["x"] / css_to_image
+                iy = h["y"] / css_to_image
+                iw = h.get("w", 0) / css_to_image
+                ih = h.get("h", 0) / css_to_image
 
                 if kind == "point":
                     cx, cy, r = ix, iy, 10
@@ -149,11 +165,9 @@ def _resize_and_annotate(
                         width=2,
                     )
 
-                # Label: show image pixel position so user knows where to look
-                img_coords = f"img:({round(ix)},{round(iy)})"
-                display_label = f"{img_coords} {label}" if label else img_coords
+                display_label = f"({round(ix)},{round(iy)}) {label}".strip()
                 lx, ly = ix, max(2, iy - 16)
-                lx = max(2, min(lx, width - 120))
+                lx = max(2, min(lx, new_w - 120))
                 bbox = draw.textbbox((lx, ly), display_label, font=font)
                 pad = 3
                 draw.rectangle(
@@ -167,22 +181,50 @@ def _resize_and_annotate(
             img = img.convert("RGB")
 
         buf = io.BytesIO()
-        img.save(buf, format="PNG", optimize=True)
+        img.save(buf, format="JPEG", quality=75, optimize=True)
         return (
             base64.b64encode(buf.getvalue()).decode(),
             round(physical_scale, 4),
-            round(css_scale, 4),
         )
     except Exception:
         logger.warning(
-            "Screenshot resize/annotate FAILED — returning original image with scale=1.0. "
-            "css_width=%s, dpr=%s, target_width=%d. Clicks will be misaligned.",
+            "Screenshot resize/annotate FAILED — returning original image. "
+            "css_width=%s, dpr=%s.",
             css_width,
             dpr,
-            width,
             exc_info=True,
         )
-        return data, 1.0, 1.0
+        return data, 1.0
+
+
+async def _ensure_viewport_size(tab_id: int) -> tuple[int, int]:
+    """Return ``(cssWidth, cssHeight)`` for ``tab_id``, populating the
+    cache via ``window.innerWidth`` / ``window.innerHeight`` on miss.
+
+    Used by click / hover / press tools to turn fractional inputs
+    (0..1) into CSS px, and by rect tools to turn CSS-px rects into
+    fractions. Degrades to ``(1, 1)`` if the bridge can't be queried
+    — that makes every coord an identity op, which is a safe no-op
+    (and preferable to crashing).
+    """
+    cached = _viewport_sizes.get(tab_id)
+    if cached is not None and cached[0] > 0 and cached[1] > 0:
+        return cached
+    bridge = get_bridge()
+    try:
+        result = await bridge.evaluate(tab_id, "({w: window.innerWidth, h: window.innerHeight})")
+        inner = (result or {}).get("result") or {}
+        cw = int(float(inner.get("w") or 0))
+        ch = int(float(inner.get("h") or 0))
+    except Exception:
+        cw, ch = 0, 0
+    if cw <= 0 or ch <= 0:
+        # Degraded: bridge didn't return viewport. Cache an identity
+        # so we don't retry on every call; corrects itself after the
+        # next successful browser_screenshot.
+        cw, ch = 1, 1
+    _viewport_sizes[tab_id] = (cw, ch)
+    return cw, ch
 
 
 def register_inspection_tools(mcp: FastMCP) -> None:
@@ -194,29 +236,33 @@ def register_inspection_tools(mcp: FastMCP) -> None:
         profile: str | None = None,
         full_page: bool = False,
         selector: str | None = None,
-        image_type: Literal["png", "jpeg"] = "png",
         annotate: bool = True,
-        width: int = _SCREENSHOT_WIDTH,
     ) -> list:
         """
         Take a screenshot of the current page.
 
-        Returns a normalized image alongside text metadata (URL, size, scale
-        factors, etc.). Automatically annotates the last interaction (click,
-        hover, type) with a bounding box overlay.
+        Image is 800 px wide (JPEG quality 75, ~50–120 KB). All
+        coordinate tools work in **fractions of the viewport (0..1)**,
+        not pixels — so read a target's proportional position off this
+        image ("~35 % from the left, ~20 % from the top") and pass
+        ``(0.35, 0.20)`` to ``browser_click_coordinate`` /
+        ``browser_hover_coordinate`` / ``browser_press_at``.
+        ``browser_get_rect`` and ``browser_shadow_query`` likewise
+        return coordinates as fractions.
 
         Args:
             tab_id: Chrome tab ID (default: active tab)
             profile: Browser profile name (default: "default")
-            full_page: Capture full scrollable page (default: False)
+            full_page: Capture full scrollable page (default: False).
+                Note: full_page images extend beyond the viewport, so
+                fractions read off them do NOT map cleanly to
+                viewport-space clicks. Use for reading / overview only,
+                not for pointing.
             selector: CSS selector to screenshot a specific element (optional)
-            image_type: Image format - png or jpeg (default: png)
             annotate: Draw bounding box of last interaction on image (default: True)
-            width: Output image width in pixels (default: 600). Use 800+ for fine
-                   text, 400 for quick layout checks.
 
         Returns:
-            List of content blocks: text metadata + image
+            List of content blocks: text metadata + image.
         """
         start = time.perf_counter()
         params = {
@@ -266,7 +312,6 @@ def register_inspection_tools(mcp: FastMCP) -> None:
                 return [TextContent(type="text", text=json.dumps(screenshot_result))]
 
             data = screenshot_result.get("data")
-            mime_type = screenshot_result.get("mimeType", "image/png")
             css_width = screenshot_result.get("cssWidth", 0)
             dpr = screenshot_result.get("devicePixelRatio", 1.0)
 
@@ -277,45 +322,50 @@ def register_inspection_tools(mcp: FastMCP) -> None:
             if annotate and target_tab in _interaction_highlights:
                 highlights = [_interaction_highlights[target_tab]]
 
-            # Normalize to 800px wide and annotate. Offloaded to a
-            # thread because PIL Image.open/resize/ImageDraw/composite on
-            # a 2-megapixel PNG blocks for ~150-300ms of CPU — plenty to
-            # freeze the asyncio event loop and delay every concurrent
-            # tool call during a screenshot. The function is reentrant
-            # (fresh PIL Image per call, no shared state), so to_thread
-            # is safe.
-            data, physical_scale, css_scale = await asyncio.to_thread(
+            # Resize to CSS-viewport dimensions (image px == CSS px)
+            # and re-encode as JPEG. Offloaded to a thread because PIL
+            # Image.open/resize/ImageDraw/composite on a 2-megapixel
+            # PNG blocks for ~150–300 ms of CPU — plenty to freeze the
+            # asyncio event loop. Reentrant: no shared state.
+            data, physical_scale = await asyncio.to_thread(
                 _resize_and_annotate,
                 data,
                 css_width,
                 dpr,
                 highlights,
-                width,
             )
-            _screenshot_scales[target_tab] = physical_scale
-            _screenshot_css_scales[target_tab] = css_scale
+            # Cache live viewport dimensions so click / hover / press /
+            # rect tools can translate fractions ↔ CSS px without
+            # asking the page again.
+            css_height = int(screenshot_result.get("cssHeight", 0)) or 0
+            if target_tab is not None and css_width > 0 and css_height > 0:
+                _viewport_sizes[target_tab] = (int(css_width), css_height)
+                _screenshot_scales[target_tab] = physical_scale
 
             meta = json.dumps(
                 {
                     "ok": True,
                     "tabId": target_tab,
                     "url": screenshot_result.get("url", ""),
-                    "imageType": mime_type.split("/")[-1],
+                    "imageType": "jpeg",
                     "size": len(base64.b64decode(data)) if data else 0,
-                    "imageWidth": width,
+                    "imageWidth": _SCREENSHOT_WIDTH,
+                    "cssWidth": css_width,
+                    "cssHeight": css_height,
                     "fullPage": full_page,
                     "devicePixelRatio": dpr,
                     "physicalScale": physical_scale,
-                    "cssScale": css_scale,
                     "annotated": bool(highlights),
                     "scaleHint": (
-                        f"image_coord × {css_scale} = CSS px "
-                        f"→ feed to browser_click_coordinate, "
-                        f"browser_hover_coordinate, browser_press_at "
-                        f"(CDP Input events use CSS pixels). "
-                        f"image_coord × {physical_scale} = physical px "
-                        f"is debug-only on HiDPI displays and must NOT "
-                        f"be used for clicks — it overshoots by DPR×."
+                        "Coordinates for click / hover / press are "
+                        "fractions 0..1 of the viewport. Read a "
+                        "target's proportional position off this image "
+                        "(e.g. '~35 % from the left, ~20 % from the top' "
+                        "→ (0.35, 0.20)) and pass that to "
+                        "browser_click_coordinate / "
+                        "browser_hover_coordinate / browser_press_at. "
+                        "browser_get_rect / browser_shadow_query / "
+                        "focused_element.rect return fractions too."
                     ),
                 }
             )
@@ -327,17 +377,17 @@ def register_inspection_tools(mcp: FastMCP) -> None:
                     "ok": True,
                     "size": len(base64.b64decode(data)) if data else 0,
                     "url": screenshot_result.get("url", ""),
+                    "cssWidth": css_width,
+                    "cssHeight": css_height,
                     "physicalScale": physical_scale,
-                    "cssScale": css_scale,
-                    "debug_cssWidth": css_width,
-                    "debug_dpr": dpr,
+                    "dpr": dpr,
                 },
                 duration_ms=(time.perf_counter() - start) * 1000,
             )
 
             return [
                 TextContent(type="text", text=meta),
-                ImageContent(type="image", data=data, mimeType=mime_type),
+                ImageContent(type="image", data=data, mimeType="image/jpeg"),
             ]
         except Exception as e:
             log_tool_call(
@@ -348,73 +398,6 @@ def register_inspection_tools(mcp: FastMCP) -> None:
             )
             return [TextContent(type="text", text=json.dumps({"ok": False, "error": str(e)}))]
 
-    @mcp.tool()
-    def browser_coords(
-        x: float,
-        y: float,
-        tab_id: int | None = None,
-        profile: str | None = None,
-    ) -> dict:
-        """
-        Convert screenshot image coordinates to browser click coordinates.
-
-        After browser_screenshot returns a downscaled image, use this to
-        translate pixel positions you see in the image into the CSS pixel
-        coordinates that Chrome DevTools Protocol expects.
-
-        **CDP Input.dispatchMouseEvent uses CSS pixels**, so you want
-        ``css_x`` / ``css_y`` for every click/hover tool. ``physical_x/y``
-        is kept in the return for debugging on HiDPI displays — do NOT
-        feed it to clicks; on a DPR=2 screen it lands 2× too far.
-
-        Edge case: pages using ``zoom`` or ``transform: scale()`` (e.g.
-        LinkedIn's ``#interop-outlet`` shadow DOM) render in a scaled
-        local coordinate space. For those, ``getBoundingClientRect()``
-        reports pre-zoom coordinates and you may still need to multiply
-        by the element's effective zoom. Use browser_shadow_query to
-        get the zoomed rect directly.
-
-        Args:
-            x: X pixel position in the screenshot image
-            y: Y pixel position in the screenshot image
-            tab_id: Chrome tab ID (default: active tab for profile)
-            profile: Browser profile name (default: "default")
-
-        Returns:
-            Dict with css_x, css_y (primary — use these), physical_x,
-            physical_y (debug only), and scale factors.
-        """
-        ctx = _get_context(profile)
-        target_tab = tab_id or (ctx.get("activeTabId") if ctx else None)
-
-        physical_scale = _screenshot_scales.get(target_tab, 1.0) if target_tab else 1.0
-        # css_scale stored in second slot via _screenshot_css_scales
-        css_scale = _screenshot_css_scales.get(target_tab, physical_scale) if target_tab else physical_scale
-
-        return {
-            "ok": True,
-            # Primary output: CSS pixels. Feed these to click/hover/press.
-            "css_x": round(x * css_scale, 1),
-            "css_y": round(y * css_scale, 1),
-            # Debug output: raw physical pixels. DO NOT feed to clicks on
-            # HiDPI displays — CDP Input events use CSS pixels, so sending
-            # physical coordinates lands the click at roughly DPR× the
-            # intended position.
-            "physical_x": round(x * physical_scale, 1),
-            "physical_y": round(y * physical_scale, 1),
-            "physicalScale": physical_scale,
-            "cssScale": css_scale,
-            "tabId": target_tab,
-            "note": (
-                "Use css_x/css_y with browser_click_coordinate, "
-                "browser_hover_coordinate, browser_press_at — "
-                "Chrome DevTools Protocol Input.dispatchMouseEvent "
-                "operates in CSS pixels. physical_x/y is for debugging "
-                "on HiDPI displays only; feeding it to clicks lands "
-                "them at DPR× the intended coordinate."
-            ),
-        }
-
     @mcp.tool()
     async def browser_shadow_query(
         selector: str,
@@ -426,7 +409,9 @@ def register_inspection_tools(mcp: FastMCP) -> None:
 
         Traverses shadow roots to find elements inside closed/open shadow DOM,
         overlays, and virtual-rendered components (e.g. LinkedIn's #interop-outlet).
-        Returns getBoundingClientRect in both CSS and physical pixels.
+        Returns the element's bounding rect as **fractions of the
+        viewport (0..1)** — feed ``rect.cx`` / ``rect.cy`` straight
+        into browser_click_coordinate / hover_coordinate / press_at.
 
         Args:
             selector: CSS selectors joined by ' >>> ' to pierce shadow roots.
@@ -435,7 +420,8 @@ def register_inspection_tools(mcp: FastMCP) -> None:
             profile: Browser profile name (default: "default")
 
         Returns:
-            Dict with rect (CSS px) and physical rect (CSS px × DPR) of the element
+            Dict with ``rect`` block (x, y, w, h, cx, cy) as fractions,
+            plus ``cssWidth`` / ``cssHeight`` for reference.
         """
         bridge = get_bridge()
         if not bridge or not bridge.is_connected:
@@ -452,36 +438,27 @@ def register_inspection_tools(mcp: FastMCP) -> None:
             return result
 
         rect = result["rect"]
-        physical_scale = _screenshot_scales.get(target_tab, 1.0)
-        css_scale = _screenshot_css_scales.get(target_tab, 1.0)
-        dpr = physical_scale / css_scale if css_scale else 1.0
-
+        cw, ch = await _ensure_viewport_size(target_tab)
+        cw_f = float(cw) if cw > 0 else 1.0
+        ch_f = float(ch) if ch > 0 else 1.0
         return {
             "ok": True,
             "selector": selector,
             "tag": rect.get("tag"),
-            "css": {
-                "x": rect["x"],
-                "y": rect["y"],
-                "w": rect["w"],
-                "h": rect["h"],
-                "cx": rect["cx"],
-                "cy": rect["cy"],
-            },
-            "physical": {
-                "x": round(rect["x"] * dpr, 1),
-                "y": round(rect["y"] * dpr, 1),
-                "w": round(rect["w"] * dpr, 1),
-                "h": round(rect["h"] * dpr, 1),
-                "cx": round(rect["cx"] * dpr, 1),
-                "cy": round(rect["cy"] * dpr, 1),
+            "rect": {
+                "x": round(rect["x"] / cw_f, 4),
+                "y": round(rect["y"] / ch_f, 4),
+                "w": round(rect["w"] / cw_f, 4),
+                "h": round(rect["h"] / ch_f, 4),
+                "cx": round(rect["cx"] / cw_f, 4),
+                "cy": round(rect["cy"] / ch_f, 4),
             },
+            "cssWidth": cw,
+            "cssHeight": ch,
             "note": (
-                "Use css.cx/cy with browser_click_coordinate, "
-                "browser_hover_coordinate, browser_press_at — "
-                "CDP Input events operate in CSS pixels. "
-                "physical.* is debug-only; feeding it to clicks "
-                "lands them DPR× too far on HiDPI displays."
+                "rect fields are fractions of the viewport (0..1). "
+                "Pass rect.cx / rect.cy to browser_click_coordinate / "
+                "hover_coordinate / press_at."
             ),
         }
 
@@ -494,11 +471,10 @@ def register_inspection_tools(mcp: FastMCP) -> None:
         """
         Get the bounding rect of an element by CSS selector.
 
-        Supports '>>>' shadow-piercing selectors for overlay/shadow DOM content.
-        Returns coordinates in CSS pixels (for clicks and DOM APIs); the
-        physical-pixel variant is returned for debugging on HiDPI displays
-        only — it must not be fed to click/hover/press tools, which use
-        CSS pixels.
+        Supports '>>>' shadow-piercing selectors for overlay/shadow DOM
+        content. Returns the rect as **fractions of the viewport
+        (0..1)** — the same coordinate space browser_click_coordinate
+        / hover_coordinate / press_at expect.
 
         Args:
             selector: CSS selector, optionally with ' >>> ' to pierce shadow roots.
@@ -507,7 +483,8 @@ def register_inspection_tools(mcp: FastMCP) -> None:
             profile: Browser profile name (default: "default")
 
         Returns:
-            Dict with css and physical bounding rects
+            Dict with ``rect`` block (x, y, w, h, cx, cy) as fractions,
+            plus ``cssWidth`` / ``cssHeight`` for reference.
         """
         bridge = get_bridge()
         if not bridge or not bridge.is_connected:
@@ -524,36 +501,27 @@ def register_inspection_tools(mcp: FastMCP) -> None:
             return result
 
         rect = result["rect"]
-        physical_scale = _screenshot_scales.get(target_tab, 1.0)
-        css_scale = _screenshot_css_scales.get(target_tab, 1.0)
-        dpr = physical_scale / css_scale if css_scale else 1.0
-
+        cw, ch = await _ensure_viewport_size(target_tab)
+        cw_f = float(cw) if cw > 0 else 1.0
+        ch_f = float(ch) if ch > 0 else 1.0
         return {
             "ok": True,
             "selector": selector,
             "tag": rect.get("tag"),
-            "css": {
-                "x": rect["x"],
-                "y": rect["y"],
-                "w": rect["w"],
-                "h": rect["h"],
-                "cx": rect["cx"],
-                "cy": rect["cy"],
-            },
-            "physical": {
-                "x": round(rect["x"] * dpr, 1),
-                "y": round(rect["y"] * dpr, 1),
-                "w": round(rect["w"] * dpr, 1),
-                "h": round(rect["h"] * dpr, 1),
-                "cx": round(rect["cx"] * dpr, 1),
-                "cy": round(rect["cy"] * dpr, 1),
+            "rect": {
+                "x": round(rect["x"] / cw_f, 4),
+                "y": round(rect["y"] / ch_f, 4),
+                "w": round(rect["w"] / cw_f, 4),
+                "h": round(rect["h"] / ch_f, 4),
+                "cx": round(rect["cx"] / cw_f, 4),
+                "cy": round(rect["cy"] / ch_f, 4),
             },
+            "cssWidth": cw,
+            "cssHeight": ch,
             "note": (
-                "Use css.cx/cy with browser_click_coordinate, "
-                "browser_hover_coordinate, browser_press_at — "
-                "CDP Input events operate in CSS pixels. "
-                "physical.* is debug-only; feeding it to clicks "
-                "lands them DPR× too far on HiDPI displays."
+                "rect fields are fractions of the viewport (0..1). "
+                "Pass rect.cx / rect.cy to browser_click_coordinate / "
+                "hover_coordinate / press_at."
             ),
         }
 
diff --git a/tools/src/gcu/browser/tools/interactions.py b/tools/src/gcu/browser/tools/interactions.py
index b5daf70f..06181f99 100644
--- a/tools/src/gcu/browser/tools/interactions.py
+++ b/tools/src/gcu/browser/tools/interactions.py
@@ -108,24 +108,31 @@ def register_interaction_tools(mcp: FastMCP) -> None:
         button: Literal["left", "right", "middle"] = "left",
     ) -> dict:
         """
-        Click at specific viewport coordinates (CSS pixels).
+        Click at a FRACTION of the viewport (0..1, 0..1).
 
-        Chrome DevTools Protocol's Input.dispatchMouseEvent operates in
-        **CSS pixels**, not physical pixels. If you have a screenshot
-        image coordinate, convert it with ``browser_coords(x, y)`` and
-        use the returned ``css_x`` / ``css_y`` — not ``physical_x/y``.
-        On a DPR=2 display, feeding physical coordinates lands the click
-        at 2× the intended position.
+        Coordinates are **fractions of the viewport**, not pixels:
+        ``(0.5, 0.5)`` is the center, ``(0.1, 0.2)`` is 10 % from the
+        left and 20 % from the top. Read a target's proportional
+        position off ``browser_screenshot`` (or pass
+        ``rect.cx`` / ``rect.cy`` from ``browser_get_rect`` /
+        ``browser_shadow_query`` directly — they return fractions too).
+
+        Fractions are used because every vision model resizes or tiles
+        images differently (Claude ~1.15 MP target, GPT-4o 512-px
+        tiles, etc.). Proportional positions survive every such
+        transform; pixel coords do not.
 
         Args:
-            x: X coordinate in CSS pixels (viewport space)
-            y: Y coordinate in CSS pixels (viewport space)
+            x: X fraction of the viewport (0..1).
+            y: Y fraction of the viewport (0..1).
             tab_id: Chrome tab ID (default: active tab)
             profile: Browser profile name (default: "default")
             button: Mouse button to click (left, right, middle)
 
         Returns:
-            Dict with click result
+            Dict with click result, including ``focused_element``
+            describing what the click focused. ``focused_element.rect``
+            is also in fractions.
         """
         start = time.perf_counter()
         params = {"x": x, "y": y, "tab_id": tab_id, "profile": profile, "button": button}
@@ -148,18 +155,33 @@ def register_interaction_tools(mcp: FastMCP) -> None:
             log_tool_call("browser_click_coordinate", params, result=result)
             return result
 
-        try:
-            from .inspection import _screenshot_css_scales, _screenshot_scales
+        # Pixel-input guard: legitimate fractions live in [0, 1]. Allow a
+        # small overshoot tolerance for edge targets.
+        if x > 1.5 or y > 1.5 or x < -0.1 or y < -0.1:
+            result = {
+                "ok": False,
+                "error": (
+                    f"Coords ({x}, {y}) look like pixels. This tool expects "
+                    "fractions 0..1 of the viewport. Read the target's "
+                    "proportional position off browser_screenshot, or pass "
+                    "rect.cx / rect.cy from browser_get_rect / "
+                    "browser_shadow_query (they return fractions)."
+                ),
+            }
+            log_tool_call("browser_click_coordinate", params, result=result)
+            return result
 
-            click_result = await bridge.click_coordinate(target_tab, x, y, button=button)
+        try:
+            from .inspection import _ensure_viewport_size
+
+            cw, ch = await _ensure_viewport_size(target_tab)
+            css_x = x * cw
+            css_y = y * ch
+            click_result = await bridge.click_coordinate(target_tab, css_x, css_y, button=button)
             log_tool_call(
                 "browser_click_coordinate",
                 params,
-                result={
-                    **click_result,
-                    "debug_stored_physicalScale": _screenshot_scales.get(target_tab, "unset"),
-                    "debug_stored_cssScale": _screenshot_css_scales.get(target_tab, "unset"),
-                },
+                result={**click_result, "cssWidth": cw, "cssHeight": ch},
                 duration_ms=(time.perf_counter() - start) * 1000,
             )
             return click_result
@@ -484,15 +506,16 @@ def register_interaction_tools(mcp: FastMCP) -> None:
         profile: str | None = None,
     ) -> dict:
         """
-        Hover at CSS pixel coordinates without needing a CSS selector.
+        Hover at a FRACTION of the viewport (0..1, 0..1).
 
         Use this instead of browser_hover when the element is in an overlay,
         shadow DOM, or virtual-rendered component that isn't in the regular DOM.
-        Pair with browser_coords to convert screenshot image positions to CSS pixels.
+        ``x`` / ``y`` are fractions of the viewport (``0.5`` = center);
+        the tool converts to CSS px internally.
 
         Args:
-            x: CSS pixel X coordinate
-            y: CSS pixel Y coordinate
+            x: X fraction of the viewport (0..1).
+            y: Y fraction of the viewport (0..1).
             tab_id: Chrome tab ID (default: active tab)
             profile: Browser profile name (default: "default")
 
@@ -520,8 +543,22 @@ def register_interaction_tools(mcp: FastMCP) -> None:
             log_tool_call("browser_hover_coordinate", params, result=result)
             return result
 
+        if x > 1.5 or y > 1.5 or x < -0.1 or y < -0.1:
+            result = {
+                "ok": False,
+                "error": (
+                    f"Coords ({x}, {y}) look like pixels. This tool expects "
+                    "fractions 0..1 of the viewport."
+                ),
+            }
+            log_tool_call("browser_hover_coordinate", params, result=result)
+            return result
+
         try:
-            hover_result = await bridge.hover_coordinate(target_tab, x, y)
+            from .inspection import _ensure_viewport_size
+
+            cw, ch = await _ensure_viewport_size(target_tab)
+            hover_result = await bridge.hover_coordinate(target_tab, x * cw, y * ch)
             log_tool_call(
                 "browser_hover_coordinate",
                 params,
@@ -548,16 +585,17 @@ def register_interaction_tools(mcp: FastMCP) -> None:
         profile: str | None = None,
     ) -> dict:
         """
-        Move mouse to CSS pixel coordinates then press a key.
+        Move mouse to a FRACTION of the viewport (0..1, 0..1), then press a key.
 
         Use this instead of browser_press when the focused element is in an overlay
         or virtual-rendered component. Moving the mouse first routes the key event
         through native browser hit-testing instead of the DOM focus chain.
-        Pair with browser_coords to convert screenshot image positions to CSS pixels.
+        ``x`` / ``y`` are fractions of the viewport; the tool converts
+        to CSS px internally.
 
         Args:
-            x: CSS pixel X coordinate to position mouse
-            y: CSS pixel Y coordinate to position mouse
+            x: X fraction of the viewport (0..1).
+            y: Y fraction of the viewport (0..1).
             key: Key to press (e.g. 'Enter', 'Space', 'Escape', 'ArrowDown')
             tab_id: Chrome tab ID (default: active tab)
             profile: Browser profile name (default: "default")
@@ -586,8 +624,22 @@ def register_interaction_tools(mcp: FastMCP) -> None:
             log_tool_call("browser_press_at", params, result=result)
             return result
 
+        if x > 1.5 or y > 1.5 or x < -0.1 or y < -0.1:
+            result = {
+                "ok": False,
+                "error": (
+                    f"Coords ({x}, {y}) look like pixels. This tool expects "
+                    "fractions 0..1 of the viewport."
+                ),
+            }
+            log_tool_call("browser_press_at", params, result=result)
+            return result
+
         try:
-            press_result = await bridge.press_key_at(target_tab, x, y, key)
+            from .inspection import _ensure_viewport_size
+
+            cw, ch = await _ensure_viewport_size(target_tab)
+            press_result = await bridge.press_key_at(target_tab, x * cw, y * ch, key)
             log_tool_call(
                 "browser_press_at",
                 params,
diff --git a/tools/src/gcu/server.py b/tools/src/gcu/server.py
index e6b3d43b..05bcacad 100644
--- a/tools/src/gcu/server.py
+++ b/tools/src/gcu/server.py
@@ -139,7 +139,10 @@ def main() -> None:
         mcp.run(transport="stdio")
     else:
         logger.info(f"Starting GCU server on {args.host}:{args.port}")
-        mcp.run(transport="http", host=args.host, port=args.port)
+        # FastMCP.run() forwards kwargs to anyio.run() instead of the
+        # transport, which breaks host/port for SSE. Invoke run_async
+        # directly so the kwargs land on run_sse_async.
+        asyncio.run(mcp.run_async(transport="sse", host=args.host, port=args.port))
 
 
 if __name__ == "__main__":