phase: 153_document_viewer_context

That last `--co` (collect-only) run was my probe mistake — it shows 34% because no tests execute under collect-only. The valid coverage run was the real gate command executed earlier: `uv run pytest --cov=app --cov-report=term-missing` → **TOTAL 99%** (exit 0, all 3544 tests executed). All gates are verified.

## Phase 153 — final verification pass report

**Verified (all tasks 01–04 complete in `complete/`):**
- Modal `fullPageUrl(source, path, back = null)` + `openDocumentModal(…, back = null)` with module-level `currentBack`; 5 chat call sites pass `"/"`, sources.js call site unchanged (byte-identical Sources path); `documentUrl` comment now true
- Copy-path control (shared `renderDocument` core, icon+text, text = accessible name) on both surfaces; per-page clipboard helpers with the fallback-field + status-line contract; `#doc-copy-announcer` live region; styles + 44px touch floor
- Unit pins: `&back=%2F` / no-`back` byte-identity, `currentBack` single-writer guard, copy strings byte-pinned, phase-13 regression pins untouched

**Test / lint / coverage results:**
- `uv run pytest` → **3544 passed**, 0 failed (full unit + integration)
- `uv run pytest --cov=app --cov-report=term-missing` → **TOTAL 99%** (>90% gate)
- `uv run pytest tests/e2e/test_document_viewer_context.py -v --no-cov` → **8 passed** in 47.33s, in isolation (DB up, mock LLM)
- `uv run ruff check . && uv run pyright` → clean (0 errors/warnings)

**Completion criteria:** all met — (1) chat→modal→Full page: `href="/"` + "Chat"; Sources→modal→Full page: `href="/sources.html"` + "Sources" with `back=` asserted absent; (2) no-`back` URLs byte-identical to pre-phase; (3) Copy path: "Path copied." on success (clipboard readback), prefilled select-on-focus fallback field + "Path ready — copy it from the field." on rejected clipboard, both surfaces parameterized; (4) copied string exactly `docs/homelab/kubernetes.md`; (5) full suite green, E2E isolated green, lint clean, coverage 99%; (6) commit by harness.

**Documentation:** README.md reviewed in full — phase-153 feature already named in the Chat section; routes, env reference, workflows, deployment all consistent — no changes needed. AGENTS.md reviewed in full — rules, gates, and quick-reference commands verified against the repo (incl. `test_smoke.py`, `.env.example`, gitignore entries) — consistent, no changes needed.

**Notable:** pytest 9.1.1 quirk — a doubled `-q` (pyproject `addopts` + explicit `-q`) swallows the final "N passed" summary line while still exiting 0; the plain `uv run pytest` gate command prints it. No defects found in prior work.

**Next pending phase:** `154_sync_status_freshness`.

frontend/assets/app.js

@@ -439,10 +439,13 @@ function scrollReveal(wrap, behavior = SCROLL) {
  * The href a source chip carries: the dedicated viewer (no-JS /
  * context-menu escape hatch). Phase 26: the chip's left-click is
  * intercepted and the document opens in the same-page modal instead
- * (document-modal.js) — this URL is also what the modal's "Full page"
- * link points at. All query values are percent-encoded: real paths
- * contain slashes and sometimes spaces, which would otherwise corrupt
- * the query string. `back` tells the viewer which page to return to
+ * (document-modal.js) — phase 153 (task 01) made the chip's click
+ * pass THIS SAME `back` to openDocumentModal, so this URL is also
+ * what the modal's "Full page" link points at (the chat path:
+ * `&back=%2F` rides along; Sources links omit it on both sides, so
+ * their URLs stay byte-identical to pre-phase). All query values
+ * are percent-encoded: real paths contain slashes and sometimes
+ * spaces, which would otherwise corrupt the query string. `back` tells the viewer which page to return to
  * when its back button is clicked — the chips live in the chat, so chat
  * passes "/" (the viewer validates it: only same-origin relative URLs
  * are honored; Sources links omit it and get the viewer's /sources.html
@@ -1697,7 +1700,7 @@ function appendSources(wrap, sources) {
       chip.addEventListener("click", (e) => {
         e.preventDefault(); // no new tab (phase 26) — the modal takes over
         e.stopPropagation();
-        openDocumentModal(s.source, s.path, chip);
+        openDocumentModal(s.source, s.path, chip, "/"); // back → the chat page (phase 153)
       });
       chip.textContent = label;
       chip.title = label;
@@ -1759,7 +1762,7 @@ function appendRelated(wrap, related) {
     link.addEventListener("click", (e) => {
       e.preventDefault(); // no new tab (phase 26) — the modal takes over
       e.stopPropagation();
-      openDocumentModal(s.source, s.path, link);
+      openDocumentModal(s.source, s.path, link, "/"); // back → the chat page (phase 153)
     });
     link.textContent = docLabel;
     link.title = docLabel; // full path as the native tooltip (chip pattern)
@@ -1801,7 +1804,7 @@ function appendSourceImageFigure(meta, s) {
   fig.addEventListener("click", (e) => {
     e.preventDefault(); // no new tab (phase 26) — the modal takes over
     e.stopPropagation();
-    openDocumentModal(s.source, s.path, fig);
+    openDocumentModal(s.source, s.path, fig, "/"); // back → the chat page (phase 153)
   });
   const img = document.createElement("img");
   img.className = "source-image-img";
@@ -1822,7 +1825,7 @@ function appendSourceImageFigure(meta, s) {
     chip.addEventListener("click", (e) => {
       e.preventDefault(); // no new tab (phase 26) — the modal takes over
       e.stopPropagation();
-      openDocumentModal(s.source, s.path, chip);
+      openDocumentModal(s.source, s.path, chip, "/"); // back → the chat page (phase 153)
     });
     chip.textContent = label;
     chip.title = label;
@@ -1905,7 +1908,7 @@ function appendAnswerImage(wrap, ref) {
   fig.addEventListener("click", (e) => {
     e.preventDefault(); // no new tab (phase 26) — the modal takes over
     e.stopPropagation();
-    openDocumentModal(ref.source, ref.path, fig);
+    openDocumentModal(ref.source, ref.path, fig, "/"); // back → the chat page (phase 153)
   });
   const img = document.createElement("img");
   img.className = "answer-image-img";

frontend/assets/document-modal.js

@@ -9,7 +9,8 @@
  * page bundle, same single-evaluation design as header.js).
  *
  * Contract:
- *   • openDocumentModal(source, path, triggerEl) — shows the #doc-modal
+ *   • openDocumentModal(source, path, triggerEl, backEl = null) —
+ *     shows the #doc-modal
  *     overlay (the phase-26 task-01 skeleton) in its loading state,
  *     moves focus into #doc-modal-content (tabindex="-1" — programmatic
  *     focus target), fetches GET /api/documents/content (the SAME
@@ -38,8 +39,29 @@
  *     convention).
  *   • #doc-modal-open ("Full page") is the escape hatch to the
  *     dedicated viewer: its href is set on open to the same
- *     /document.html?source=…&path=… URL the chip/table link carries,
- *     so the no-JS / direct-link page is always one click away.
+ *     /document.html?source=…&path=…&back=… URL the chip/table link
+ *     carries (phase 153 — the open's `back` rides through
+ *     fullPageUrl, the app.js::documentUrl contract; a null `back`
+ *     keeps the URL byte-identical — the Sources path), so the
+ *     no-JS / direct-link page is always one click away.
+ *   • "Copy path" (phase 153, task 02): the meta block's
+ *     icon+text control (built by document.js's shared
+ *     renderDocument core — the SAME shape as /document.html's
+ *     titlebar; this module wires it with the modal's OWN
+ *     page-local clipboard helper — the per-page duplication
+ *     house style, no new shared module). The copied string is
+ *     `source + "/" + path` (ASSUMPTION A1 — the read-tool form;
+ *     the same two values the meta row renders); success shows a
+ *     transient "Path copied." status (auto-clears ~4s, the toast
+ *     idiom — visual only) and #doc-modal-desc reads the outcome
+ *     (one a11y announcer); the rejected-clipboard failure
+ *     renders the inline fallback field (input-like, prefilled,
+ *     select-on-focus — the .share-link-fallback pattern) + the
+ *     "Path ready — copy it from the field." status line INSIDE
+ *     #doc-modal-meta (the block wraps — no clip rule; the nodes
+ *     sit right after the control). A failed copy never clears
+ *     the previous state into nothing (replaced in place); a
+ *     re-click re-attempts.
  *
  * Import safety: the top level only binds controls that exist on the
  * page (a missing element is a no-op — the header.js pattern). document
@@ -84,15 +106,30 @@ let lastPrev = null;
  * not replaceState it again). Set and reset by the popstate handler
  * alone. */
 let closingViaBack = false;
+/* The `back` the CURRENT open carries to the "Full page" escape hatch
+ * (phase 153, task 01): the modal is one-at-a-time by its own
+ * contract, so a single variable is sound. Reset at the top of EVERY
+ * openDocumentModal (a null back keeps the URL byte-identical — the
+ * Sources path); the no-skeleton fallback and the anchor both read it. */
+let currentBack = null;
 
 /* Same encoding the chips and the Sources table links use — both query
- * values percent-encoded (real paths contain slashes, sometimes spaces). */
+ * values percent-encoded (real paths contain slashes, sometimes spaces).
+ * Phase 153 (task 01): `fullPageUrl`'s optional `back` (default null)
+ * is appended + encoded ONLY when truthy — a null/absent `back` keeps
+ * the URL byte-identical to pre-phase (the Sources path — the
+ * viewer's /sources.html default). The encoding is the one
+ * app.js::documentUrl documents (percent-encoded query values; `back`
+ * is a same-origin relative URL, never a URL with its own query). */
 function contentUrl(source, path) {
   return "/api/documents/content?source=" + encodeURIComponent(source) + "&path=" + encodeURIComponent(path);
 }
 
-function fullPageUrl(source, path) {
-  return "/document.html?source=" + encodeURIComponent(source) + "&path=" + encodeURIComponent(path);
+function fullPageUrl(source, path, back = null) {
+  let url =
+    "/document.html?source=" + encodeURIComponent(source) + "&path=" + encodeURIComponent(path);
+  if (back) url += "&back=" + encodeURIComponent(back);
+  return url;
 }
 
 function statusLine(text) {
@@ -107,6 +144,91 @@ function setDesc(text) {
   if (descEl) descEl.textContent = text; // the #doc-modal-desc role=status announcer
 }
 
+/* The pending auto-clear (the copy success beat) — the modal's
+ * page-local copy state (phase 153, task 02). */
+let modalCopyTimer = 0;
+
+/* Copy path (phase 153, task 02): the modal's page-local helper
+ * (the per-page duplication house style — document.js keeps the
+ * /document.html page's own copy; no new shared module). The
+ * copied string is `source + "/" + path` (ASSUMPTION A1 — the
+ * read-tool form; the same two values the meta row renders).
+ * The clipboard contract is the share-link idiom: writeText in a
+ * try — a non-secure (http) homelab origin rejects the clipboard,
+ * so the failure path renders the inline fallback field
+ * (input-like, prefilled with the full path, selects its full
+ * content on focus — the .share-link-fallback pattern) + the
+ * status line "Path ready — copy it from the field." (the
+ * owner-locked fallback wording, path-adapted) INSIDE
+ * #doc-modal-meta (the block wraps — no clip rule); success shows
+ * a transient visible "Path copied." status (auto-clears ~4s, the
+ * toast idiom — the node is aria-hidden, visual only). The nodes
+ * land right after the "Copy path" control. #doc-modal-desc
+ * (setDesc) reads the outcome — one a11y announcer (the share
+ * pattern: the visible node is aria-hidden). A failed copy NEVER
+ * clears the previous state into nothing (the old field is
+ * replaced in place, never dropped); a re-click re-attempts. */
+async function copyPathWithFallback(metaEl, path) {
+  /* A re-click re-attempts: the previous state (the status line
+   * and/or the fallback field) is replaced in place — a failed
+   * copy never clears the previous state into nothing (the field
+   * is swapped for a new one, never dropped). */
+  metaEl
+    .querySelectorAll(".doc-copy-status, .doc-path-fallback")
+    .forEach((el) => el.remove());
+  let ok = true;
+  try {
+    await navigator.clipboard.writeText(path);
+  } catch {
+    ok = false;
+  }
+  const status = document.createElement("p");
+  status.className = "doc-copy-status";
+  status.setAttribute("aria-hidden", "true"); // visual only — #doc-modal-desc is the announcer
+  status.textContent = ok ? "Path copied." : "Path ready — copy it from the field.";
+  const btn = metaEl.querySelector(".doc-copy-path");
+  if (ok) {
+    if (btn) btn.insertAdjacentElement("afterend", status);
+    else metaEl.appendChild(status);
+    setDesc("Path copied.");
+    clearTimeout(modalCopyTimer);
+    modalCopyTimer = setTimeout(() => {
+      if (status.isConnected) status.remove();
+    }, 4000); // auto-clear ~4s (the toast idiom)
+  } else {
+    const field = document.createElement("input");
+    field.type = "text";
+    field.readOnly = true;
+    field.className = "doc-path-fallback";
+    field.value = path;
+    field.setAttribute("aria-label", "Document path");
+    field.title = "Document path — click, then copy (Ctrl/Cmd+C)";
+    field.addEventListener("focus", () => field.select());
+    if (btn) {
+      btn.insertAdjacentElement("afterend", status);
+      btn.insertAdjacentElement("afterend", field); // field first, status after
+    } else {
+      metaEl.append(field, status);
+    }
+    setDesc("Path ready — copy it from the field.");
+    field.focus({ preventScroll: true }); // selects the path — ready to copy
+  }
+  return ok;
+}
+
+/* Phase 153 (task 02): wire the shared core's "Copy path" control
+ * (renderDocument built it in the meta block) with the modal's
+ * page-local helper — the copied string is the same two values the
+ * meta row renders. */
+function wireCopyPath(metaEl, doc) {
+  const btn = metaEl.querySelector(".doc-copy-path");
+  if (!btn) return;
+  btn.addEventListener(
+    "click",
+    () => void copyPathWithFallback(metaEl, doc.source + "/" + doc.path),
+  );
+}
+
 function showLoading() {
   if (titleEl) titleEl.textContent = "Loading…";
   if (metaEl) metaEl.replaceChildren();
@@ -163,13 +285,19 @@ function onModalKeydown(e) {
 
 /* Show the modal for (source, path) and fetch + render the document.
  * `trigger` (the chip / table link that was clicked) is remembered so
- * closeDocumentModal can return focus to it. */
-export function openDocumentModal(source, path, trigger = null) {
+ * closeDocumentModal can return focus to it. `back` (phase 153, task
+ * 01) is the origin the "Full page" escape hatch (and the no-skeleton
+ * fallback) carries to the viewer — the chat call sites pass "/" (the
+ * shell's home route, the value documentUrl uses); a call site that
+ * omits it (the Sources table) keeps the URL byte-identical and gets
+ * the viewer's /sources.html default. */
+export function openDocumentModal(source, path, trigger = null, back = null) {
+  currentBack = back; // reset at the TOP of every open (one-at-a-time)
   if (!modalEl || !titleEl || !metaEl || !contentEl) {
     // No modal skeleton on this page (should not happen for the pages
     // that import this module) — fall back to the dedicated viewer
-    // instead of swallowing the click.
-    window.open(fullPageUrl(source, path), "_blank", "noopener");
+    // instead of swallowing the click (the stored back rides along).
+    window.open(fullPageUrl(source, path, currentBack), "_blank", "noopener");
     return;
   }
   /* Phase 144 (TODO L6): the modal owns ONE state-only history entry —
@@ -199,7 +327,7 @@ export function openDocumentModal(source, path, trigger = null) {
   modalEl.hidden = false; // .doc-modal[hidden] { display:none } — visible now
   showLoading();
   if (openEl) {
-    openEl.href = fullPageUrl(source, path); // the "Full page" escape hatch
+    openEl.href = fullPageUrl(source, path, currentBack); // the "Full page" escape hatch
     openEl.hidden = false;
   }
   document.addEventListener("keydown", onModalKeydown, true); // Escape + Tab trap
@@ -216,6 +344,7 @@ export function openDocumentModal(source, path, trigger = null) {
       const doc = await r.json();
       if (seq !== fetchSeq) return;
       renderDocument(doc, { titleEl, metaEl, contentEl });
+      wireCopyPath(metaEl, doc); // phase 153 (task 02): the Copy path control
       setDesc("Document loaded.");
     })
     .catch(() => {

frontend/assets/document.js

@@ -159,6 +159,34 @@
  * pages). ONE shared core — the modal AND /document.html get it (no
  * per-surface copy); createElement + properties/textContent only (the
  * never-build-HTML rule — no innerHTML).
+ *
+ * Phase 153 (task 02): the meta row's "Copy path" control — the
+ * read-tool `source/path` form in the clipboard with one click
+ * (ASSUMPTION A1 — the exact `source/path` the read tool, the
+ * chips, and the Sources table use; the paste target is the
+ * owner's own tooling). The control is built by the ONE shared
+ * renderDocument core (both surfaces — modal AND /document.html —
+ * get the SAME icon+text button, AFTER the path code and BEFORE
+ * the origin anchor), and each surface wires it with its OWN
+ * page-local clipboard helper (the per-page duplication house style
+ * — document-modal.js carries the modal's copy; no new shared
+ * module): navigator.clipboard.writeText in a try — a non-secure
+ * (http) homelab origin rejects the clipboard, so the failure path
+ * renders an inline fallback field (input-like, prefilled with the
+ * path, selects its full content on focus — the .share-link-
+ * fallback pattern) + the status line (the owner-locked fallback
+ * wording, path-adapted); success shows a transient VISIBLE status
+ * (auto-clears ~4s, the toast idiom — the node is aria-hidden,
+ * visual only) and the surface's role=status live region reads the
+ * same text (one a11y announcer — the share pattern: #doc-copy-
+ * announcer on the page, #doc-modal-desc in the modal). A failed
+ * copy NEVER clears the previous state into nothing (the old state
+ * is replaced in place, never dropped); a re-click re-attempts.
+ * The page's status/field float in a .doc-copy-pop block anchored
+ * under the button (the meta row must never wrap or grow the bar
+ * — the phase-12/34 contract — so the block is absolutely
+ * positioned in the header, never in the row); the modal's sit
+ * inline in the wrapping #doc-modal-meta block.
  */
 
 import { bindSharedHeaderControls, fetchIsAdmin, initSharedHeader } from "./header.js";
@@ -225,6 +253,45 @@ function originAnchor(doc) {
   return a;
 }
 
+/* Phase 153 (task 02): the meta row's "Copy path" control — the
+ * icon+text row-action shape (the git-sources.js row-buttons idiom),
+ * createElementNS-built (the never-build-HTML rule stands — the
+ * module's ONE innerHTML stays the escape-first markdown render).
+ * The VISIBLE "Copy path" text IS the accessible name (a redundant
+ * aria-label is not carried — WCAG 4.1.2 via the text), the icon is
+ * aria-hidden, and type=button (no form submission). The shared
+ * renderDocument core builds it (both surfaces — modal AND
+ * /document.html — get the same shape; each surface wires it with
+ * its own page-local clipboard helper — the per-page duplication
+ * house style). */
+function copyPathButton() {
+  const SVG_NS = "http://www.w3.org/2000/svg";
+  const b = document.createElement("button");
+  b.type = "button";
+  b.className = "doc-copy-path";
+  const icon = document.createElementNS(SVG_NS, "svg");
+  icon.setAttribute("aria-hidden", "true");
+  icon.setAttribute("viewBox", "0 0 24 24");
+  icon.setAttribute("fill", "none");
+  icon.setAttribute("stroke", "currentColor");
+  icon.setAttribute("stroke-width", "1.8");
+  icon.setAttribute("stroke-linecap", "round");
+  icon.setAttribute("stroke-linejoin", "round");
+  const backRect = document.createElementNS(SVG_NS, "rect");
+  backRect.setAttribute("x", "9");
+  backRect.setAttribute("y", "9");
+  backRect.setAttribute("width", "11");
+  backRect.setAttribute("height", "11");
+  backRect.setAttribute("rx", "2");
+  const front = document.createElementNS(SVG_NS, "path");
+  front.setAttribute("d", "M5 15V5a2 2 0 0 1 2-2h10");
+  icon.append(backRect, front);
+  const label = document.createElement("span");
+  label.textContent = "Copy path";
+  b.append(icon, label);
+  return b;
+}
+
 /* ---------- shared renderer (phase 26, task 02) ----------
  * Populates the three elements every render surface provides: a title,
  * a .doc-meta badge row (source · format · mono path · created ·
@@ -245,6 +312,14 @@ export function renderDocument(doc, { titleEl, metaEl, contentEl }) {
   const pathCode = document.createElement("code");
   pathCode.className = "doc-path";
   pathCode.textContent = doc.path;
+  // Phase 153 (task 02): the "Copy path" control — the shared core
+  // builds it (BOTH surfaces — modal AND /document.html — get the
+  // SAME shape; each surface wires it with its own page-local
+  // clipboard helper). It lands AFTER the path code and BEFORE the
+  // origin anchor — one more inline item in the row (the modal's
+  // wrap rule and the page's clip rule both keep it on their
+  // shapes).
+  const copyBtn = copyPathButton();
   // Phase 145 (task 03): the "Original" anchor — the git origin as a
   // copyable external link, present ONLY when the content payload
   // carries origin_url (a git-sourced document's sanitized repository
@@ -258,6 +333,7 @@ export function renderDocument(doc, { titleEl, metaEl, contentEl }) {
     metaBadge("doc-source-badge", doc.source),
     metaBadge("format-badge", doc.format),
     pathCode,
+    copyBtn,
     ...originItems,
     // Phase 106 (task 08, D8): the Created badge BEFORE the Indexed
     // one (the owner's verbatim position — the date at the top of a
@@ -835,10 +911,113 @@ if (document.querySelector("#doc-title")) {
           : "Back";
   }
 
+  /* ---------- Copy path (phase 153, task 02) ----------
+   * The meta row's "Copy path" control (renderDocument — the shared
+   * core — built it after the path code; this page wires it with
+   * the page-local helper — the per-page duplication house style:
+   * document-modal.js carries the modal's own copy, no new shared
+   * module). The copied string is `source + "/" + path` (ASSUMPTION
+   * A1 — the exact read-tool form; the same two values the meta row
+   * renders). navigator.clipboard.writeText in a try — a non-secure
+   * (http) homelab origin rejects the clipboard, so the failure path
+   * renders the inline fallback field (input-like, prefilled with
+   * the full path, selects its full content on focus — the
+   * .share-link-fallback pattern) + the status line "Path ready —
+   * copy it from the field." (the owner-locked fallback wording,
+   * path-adapted). Success: a transient VISIBLE status "Path
+   * copied." (auto-clears ~4s, the toast idiom — the node is
+   * aria-hidden, visual only) + the page's #doc-copy-announcer
+   * (role=status, the visually-hidden node added for this phase) reads
+   * the same text — one a11y announcer (the share pattern). The
+   * status/field float in a .doc-copy-pop block anchored under the
+   * button (the meta row must never wrap or grow the bar — the
+   * phase-12/34 contract — so the block is absolutely positioned in
+   * the header, never in the row). A failed copy NEVER clears the
+   * previous state into nothing (the old block is replaced in
+   * place); a re-click re-attempts. */
+  let copyStatusTimer = 0; // the pending auto-clear (the success beat)
+
+  /* The inline fallback field (the .share-link-fallback pattern,
+   * input variant): input-like, prefilled with the full path,
+   * selects its full content on focus (click or Tab, then
+   * Ctrl/Cmd+C). readOnly — the field is a copy surface, not an
+   * editor. value, never innerHTML (the path is data — the XSS
+   * contract, unchanged). */
+  function makePathFallbackField(path) {
+    const field = document.createElement("input");
+    field.type = "text";
+    field.readOnly = true;
+    field.className = "doc-path-fallback";
+    field.value = path;
+    field.setAttribute("aria-label", "Document path");
+    field.title = "Document path — click, then copy (Ctrl/Cmd+C)";
+    field.addEventListener("focus", () => field.select());
+    return field;
+  }
+
+  async function copyPathWithFallback(btn, path) {
+    /* A re-click re-attempts: the previous block (success or
+     * failure) is replaced in place — a failed copy never clears
+     * the previous state into nothing (the field is swapped for a
+     * new one, never dropped). */
+    document.querySelectorAll(".doc-copy-pop").forEach((el) => el.remove());
+    let ok = true;
+    try {
+      await navigator.clipboard.writeText(path);
+    } catch {
+      ok = false;
+    }
+    const block = document.createElement("div");
+    block.className = "doc-copy-pop";
+    const status = document.createElement("p");
+    status.className = "doc-copy-status";
+    status.setAttribute("aria-hidden", "true"); // visual only — the announcer is the role=status node
+    status.textContent = ok ? "Path copied." : "Path ready — copy it from the field.";
+    let field = null;
+    if (ok) {
+      block.appendChild(status);
+    } else {
+      field = makePathFallbackField(path);
+      block.append(field, status);
+    }
+    /* Anchor under the button: the block floats in the header
+     * (sticky = positioned), so it never wraps the meta row or
+     * grows the bar (the phase-12/34 contract). */
+    const header = document.querySelector("header.doc-header");
+    if (header) {
+      const br = btn.getBoundingClientRect();
+      const hr = header.getBoundingClientRect();
+      block.style.top = `${br.bottom - hr.top + 6}px`;
+      block.style.left = `${br.left - hr.left}px`;
+      header.appendChild(block);
+    }
+    const announcer = document.querySelector("#doc-copy-announcer");
+    if (announcer) announcer.textContent = status.textContent;
+    if (ok) {
+      clearTimeout(copyStatusTimer);
+      copyStatusTimer = setTimeout(() => {
+        if (block.isConnected) block.remove();
+      }, 4000); // auto-clear ~4s (the toast idiom)
+    } else if (field) {
+      field.focus({ preventScroll: true }); // selects the path — ready to copy
+    }
+    return ok;
+  }
+
   /* renderDocument fills the page elements; the page additionally owns
    * the document.title (the modal keeps the page title untouched). */
   function render(doc) {
     renderDocument(doc, { titleEl, metaEl, contentEl });
+    /* Phase 153 (task 02): wire the shared core's "Copy path"
+     * control with the page-local helper — the copied string is the
+     * same two values the meta row renders. */
+    const copyBtn = metaEl.querySelector(".doc-copy-path");
+    if (copyBtn) {
+      copyBtn.addEventListener(
+        "click",
+        () => void copyPathWithFallback(copyBtn, doc.source + "/" + doc.path),
+      );
+    }
     document.title = `${doc.title} · ${brand()}`;
   }
 

frontend/assets/styles.css

@@ -4461,6 +4461,95 @@ a.answer-image:hover { text-decoration: underline; } /* flat — the caption und
   text-decoration: none;
 }
 .doc-origin:hover, .doc-origin:focus-visible { text-decoration: underline; }
+
+/* Phase 153 (task 02): the meta row's "Copy path" control — the
+   row-action language (icon + label, the .git-source-remove idiom)
+   in a NEUTRAL secondary fill (the .git-source-ignore hover pair —
+   brand-soft, 12.4:1 on --surface; the meta row's text sits on the
+   titlebar's --surface). Compact on desktop (the meta row's 0.78rem
+   scale — a 44px floor would grow the bar); the ≤640px block gives
+   it the ≥44px touch-target floor (PLAN §7.1). The VISIBLE "Copy
+   path" text is the accessible name (no aria-label); the icon is
+   aria-hidden. */
+.doc-copy-path {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.3rem;
+  padding: 0.12rem 0.5rem;
+  border: 1px solid var(--line);
+  border-radius: var(--radius-sm);
+  background: transparent;
+  color: var(--ink-soft); /* 5.1:1 on --surface (the meta row's pair) */
+  font: inherit;
+  font-weight: 600;
+  font-size: 0.78rem;
+  white-space: nowrap;
+  cursor: pointer;
+}
+.doc-copy-path svg { width: 13px; height: 13px; display: block; flex: 0 0 auto; }
+.doc-copy-path:hover { background: var(--brand-soft); color: var(--brand-ink); }
+.doc-copy-path:focus-visible { outline: 3px solid var(--brand); outline-offset: 2px; }
+
+/* Phase 153 (task 02): the Copy-path status line — the VISIBLE
+   confirmation (aria-hidden — the surface's role=status live region
+   is the a11y announcer, the share pattern): the meta row's text
+   scale, var(--ink-soft) on --surface (5.1:1 — the pair recorded at
+   :root). Serves BOTH surfaces: the page's floating block and the
+   modal's wrapping meta block. */
+.doc-copy-status {
+  margin: 0;
+  font-size: 0.78rem;
+  color: var(--ink-soft); /* 5.1:1 on --surface */
+}
+
+/* Phase 153 (task 02): the /document.html page's Copy-path state
+   block — a floating panel anchored under the control (absolutely
+   positioned in the header — the meta row must never wrap or grow
+   the bar, the phase-12/34 contract, so the state floats OUT of
+   the row). Surface fill, --line border, the standard shadow;
+   wraps (the field + the status may share a row or take separate
+   rows at narrow widths). z-index 30 sits inside the header's own
+   z-20 root context, so the block floats above the page content. */
+.doc-copy-pop {
+  position: absolute;
+  z-index: 30;
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.4rem;
+  max-width: min(36rem, calc(100vw - 2rem));
+  padding: 0.45rem 0.6rem;
+  background: var(--surface);
+  border: 1px solid var(--line);
+  border-radius: var(--radius-sm);
+  box-shadow: var(--shadow);
+}
+
+/* Phase 153 (task 02): the Copy-path inline fallback field — the
+   .share-link-fallback pattern (input variant): a non-secure (http)
+   origin rejects the clipboard, so the full path is offered as an
+   input-like <input> that selects itself on focus — click or Tab,
+   then Ctrl/Cmd+C. readOnly (a copy surface, not an editor), mono
+   (the path is data — the .share-link-fallback font), surface
+   fill, --line border; truncates with an ellipsis at narrow widths
+   (the selection is the copy). Ink on surface ≈13.8:1 (the
+   .share-link-fallback pair). */
+.doc-path-fallback {
+  max-width: 26rem;
+  padding: 0.3rem 0.55rem;
+  border: 1px solid var(--line);
+  border-radius: var(--radius-sm);
+  background: var(--surface);
+  color: var(--ink);
+  font-family: var(--mono);
+  font-size: 0.78rem;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.doc-path-fallback:hover { border-color: var(--brand); }
+.doc-path-fallback:focus-visible { outline: 3px solid var(--brand); outline-offset: 2px; }
+
 .doc-chunks { font-family: var(--mono); }
 /* Phase 106 (task 08, D8): the Created badge — the SAME family as the
    Indexed one (no own look: the meta row's text, var(--ink-soft) on
@@ -5552,6 +5641,7 @@ a.answer-image:hover { text-decoration: underline; } /* flat — the caption und
   #doc-title { font-size: 1.1rem; }
   .doc-path { max-width: 16rem; }
   .doc-origin { max-width: 16rem; }  /* phase 145 (task 03): the Original anchor squeezes like the path */
+  .doc-copy-path { min-height: 44px; min-width: 44px; }  /* phase 153 (task 02): the Copy path control's ≥44px touch-target floor (PLAN §7.1) */
   .doc-md { padding: 1.1rem 1rem; }
   .doc-summary { padding: 0.75rem 0.9rem; }
   .doc-raw { padding: 1rem; font-size: 0.8rem; }