diff --git a/plugins/knowledge/.claude-plugin/plugin.json b/plugins/knowledge/.claude-plugin/plugin.json
index e14d388e4e..087271a663 100644
--- a/plugins/knowledge/.claude-plugin/plugin.json
+++ b/plugins/knowledge/.claude-plugin/plugin.json
@@ -1,6 +1,6 @@
 {
   "name": "knowledge",
-  "version": "0.19.0",
+  "version": "0.19.1",
   "description": "Ingests external knowledge into synthesized artifacts: book-distill (PDF or EPUB into author-attributed reference files), video-digest (one YouTube or X video: transcript, links, repo applicability), course-digest (Dometrain and Teachable courses into recommendations), docpage-digest (one documentation page into a verified knowledge slice), and map-corpus (a multi-resource corpus into a classified link map and an approved docpage-digest queue). setup sets where artifacts land.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/knowledge/CHANGELOG.md b/plugins/knowledge/CHANGELOG.md
index c0867f1da8..3346a8ab6c 100644
--- a/plugins/knowledge/CHANGELOG.md
+++ b/plugins/knowledge/CHANGELOG.md
@@ -4,6 +4,21 @@ All notable changes to the `knowledge` plugin are recorded here. The `version` i
 `.claude-plugin/plugin.json` is the delivery vehicle. A consumer receives a change
 only after that version increases.
 
+## [0.19.1] - 2026-10-03
+
+### Fixed
+
+- **`video-digest` and `course-digest` install into and load from the knowledge plugin's own data
+  directory, whatever `CLAUDE_PLUGIN_DATA` the Bash tool's shell holds.** Another plugin's
+  SessionStart hook can export its own data directory under that name for every Bash call, and
+  `setup-deps.mjs` installed the extraction dependencies there. `run.mjs` and `setup-deps.mjs`
+  now take a leading `--data-dir`, which every documented command passes as
+  `"${CLAUDE_PLUGIN_DATA}"` (or `"<plugin-data>"` in the spoke files). Without the flag they
+  accept an inherited value only when it names this plugin, and `setup-deps.mjs` stops before
+  writing anything when no directory resolves. The pre-computed dependency checks read the
+  substituted path, and the bootstrap recovery command names the launcher by absolute path with
+  the resolved `--data-dir`.
+
 ## [0.19.0] - 2026-10-02
 
 ### Added
diff --git a/plugins/knowledge/skills/course-digest/SKILL.md b/plugins/knowledge/skills/course-digest/SKILL.md
index d0cf1202ac..aaa051950c 100644
--- a/plugins/knowledge/skills/course-digest/SKILL.md
+++ b/plugins/knowledge/skills/course-digest/SKILL.md
@@ -11,8 +11,8 @@ shell: bash
 ## Pre-computed context
 
 ```!
-{ printf 'course-extraction deps: '; node -e "const fs=require('fs'),path=require('path'),p=process.env.CLAUDE_PLUGIN_DATA;console.log(p&&fs.existsSync(path.join(p,'node_modules','@melodic','video-digestion'))?'installed':'MISSING - run setup-deps.mjs (see Prerequisites)')" 2>/dev/null || echo "MISSING - node not found (see Prerequisites)"; }
-{ printf 'Playwright Chromium: '; node -e "const fs=require('fs'),path=require('path');const b=process.env.PLAYWRIGHT_BROWSERS_PATH||(process.env.CLAUDE_PLUGIN_DATA&&path.join(process.env.CLAUDE_PLUGIN_DATA,'ms-playwright'));const ok=b&&fs.existsSync(b)&&fs.readdirSync(b).some(n=>n.startsWith('chromium'));console.log(ok?'installed':'MISSING - run setup-deps.mjs (see Prerequisites)')" 2>/dev/null || echo "MISSING - node not found (see Prerequisites)"; }
+{ printf 'course-extraction deps: '; node -e "const fs=require('fs'),path=require('path'),p=process.argv[1];console.log(p&&fs.existsSync(path.join(p,'node_modules','@melodic','video-digestion'))?'installed':'MISSING - run setup-deps.mjs (see Prerequisites)')" "${CLAUDE_PLUGIN_DATA}" 2>/dev/null || echo "MISSING - node not found (see Prerequisites)"; }
+{ printf 'Playwright Chromium: '; node -e "const fs=require('fs'),path=require('path');const b=process.env.PLAYWRIGHT_BROWSERS_PATH||(process.argv[1]&&path.join(process.argv[1],'ms-playwright'));const ok=b&&fs.existsSync(b)&&fs.readdirSync(b).some(n=>n.startsWith('chromium'));console.log(ok?'installed':'MISSING - run setup-deps.mjs (see Prerequisites)')" "${CLAUDE_PLUGIN_DATA}" 2>/dev/null || echo "MISSING - node not found (see Prerequisites)"; }
 { printf 'ffmpeg: '; command -v ffmpeg >/dev/null 2>&1 && { ffmpeg -version 2>/dev/null | head -1; :; } || echo "MISSING — install ffmpeg (see Prerequisites)"; }
 { printf 'ImageMagick: '; command -v magick >/dev/null 2>&1 && { magick -version 2>/dev/null | head -1; :; } || echo "MISSING — install ImageMagick 7 (see Prerequisites)"; }
 ```
@@ -35,7 +35,7 @@ This skill's `.work/` root resolves through the knowledge plugin's own `library_
 
 ## Prerequisites (verify before starting)
 
-1. **course-extraction deps**. `node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/setup-deps.mjs"`. Installs the pipeline's node dependencies into `${CLAUDE_PLUGIN_DATA}` (persists across plugin updates) and provisions Playwright's Chromium into `${CLAUDE_PLUGIN_DATA}/ms-playwright`. Idempotent. Safe to re-run, and re-run after a plugin update.
+1. **course-extraction deps**. `node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/setup-deps.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}"`. Installs the pipeline's node dependencies into `${CLAUDE_PLUGIN_DATA}` (persists across plugin updates) and provisions Playwright's Chromium into `${CLAUDE_PLUGIN_DATA}/ms-playwright`. Idempotent. Safe to re-run, and re-run after a plugin update.
 2. **Platform auth**. Set `COURSE_EMAIL`/`COURSE_PASSWORD` (Dometrain → Clerk) or `TEACHABLE_EMAIL`/`TEACHABLE_PASSWORD` (Teachable) in your shell before invoking; they inherit into the pipeline's node subprocess. The env-var prefix is course-config-driven via `platformConfig.authEnvPrefix`. Session cookies persist under `${CLAUDE_PLUGIN_DATA}/auth/<platform>.auth-state.json` and are reused across runs. **Interactive manual login is the fallback** when no credentials are set. It opens a browser window for you to log in. NOTE: the manual-login prompt (`node:readline` + headed browser) may not function under headless plugin execution; env-var + cookie-reuse carry the skill regardless, and manual login is a known limitation there, not a blocker. These credentials live in shell environment variables, not in plugin `userConfig`: this plugin's `userConfig` options are non-secret scalars, and a stored option value is not a secret store.
 3. **ffmpeg**, required for video frame extraction (scene detection, interval capture). Check: `ffmpeg -version`. Install: `winget install Gyan.FFmpeg` (Windows), `brew install ffmpeg` (macOS), `sudo apt install ffmpeg` (Linux). Floor 7.1+ (newer codecs, AV1, Opus, degrade or fail below this).
 4. **ImageMagick 7**, required by `classify-frames.js` for contact sheet generation (`magick montage`). Check: `magick -version`. Install: `winget install ImageMagick.ImageMagick` (Windows), `brew install imagemagick` (macOS), `sudo apt install imagemagick` (Linux). Ubuntu <26.04 ships v6. V7 may require building from source.
@@ -45,10 +45,10 @@ If any prerequisite fails, stop and inform the user. Re-run `setup-deps.mjs` for
 
 ## Running the pipeline scripts
 
-Every extraction script runs through the launcher, which resolves the vendored node dependencies from `${CLAUDE_PLUGIN_DATA}` and pins Playwright's browser path:
+Every extraction script runs through the launcher, which resolves the vendored node dependencies from the data directory its leading `--data-dir` names and pins Playwright's browser path:
 
 ```bash
-node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" <script.js> [args…]
+node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" <script.js> [args…]
 ```
 
 Gate on `setup-deps.mjs` first (Prerequisites above).
@@ -59,16 +59,16 @@ The Playwright batch script handles transcripts, video frame extraction, and cou
 
 ```bash
 # Full extraction: transcripts + frames + metadata
-node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" extract-course.js --course-dir <path-to-course-data> --extract-frames
+node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" extract-course.js --course-dir <path-to-course-data> --extract-frames
 
 # Transcripts only (faster, no ffmpeg needed)
-node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" extract-course.js --course-dir <path-to-course-data>
+node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" extract-course.js --course-dir <path-to-course-data>
 
 # Frames only (skip transcripts already extracted)
-node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" extract-course.js --course-dir <path-to-course-data> --extract-frames --skip-transcripts
+node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" extract-course.js --course-dir <path-to-course-data> --extract-frames --skip-transcripts
 
 # Course metadata only
-node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" extract-course.js --course-dir <path-to-course-data> --metadata-only
+node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" extract-course.js --course-dir <path-to-course-data> --metadata-only
 ```
 
 Script uses Playwright's bundled Chromium with a fresh temp context (not Chrome itself. Chrome 136+ blocks CDP on default profiles). Auth handled via `addCookies()` after context launch: with credentials set it logs in and saves state; subsequent runs inject cached cookies automatically. Skips already-extracted lessons (crash-safe, resumable). Runs headless by default (`--show-browser` to show the browser).
@@ -88,7 +88,7 @@ Script uses Playwright's bundled Chromium with a fresh temp context (not Chrome
 
 ```bash
 # Run in background with nohup — no timeout limit
-nohup node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" extract-course.js --course-dir <path> > extraction.log 2>&1 &
+nohup node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" extract-course.js --course-dir <path> > extraction.log 2>&1 &
 echo $!  # save PID
 
 # Monitor progress periodically
@@ -237,12 +237,20 @@ Repo-applicability analysis follows the template in [reference/analysis-template
 
 ## Spoke paths
 
-The `context/` files write this skill's directory as `<skill-dir>`, which is `${CLAUDE_SKILL_DIR}`.
-Put that path in place of the placeholder before running a command. Those files arrive through the
-Read tool as plain bytes, so a `${…}` token in them would reach the Bash tool unsubstituted, and the
-Bash tool's environment has no `CLAUDE_SKILL_DIR` to expand it from. Basis: the plugins reference,
+The `context/` files write this skill's directory as `<skill-dir>`, which is `${CLAUDE_SKILL_DIR}`,
+and the plugin data directory as `<plugin-data>`, which is `${CLAUDE_PLUGIN_DATA}`. Put those paths
+in place of the placeholders before running a command. Those files arrive through the Read tool as
+plain bytes, so a `${…}` token in them would reach the Bash tool unsubstituted, and the Bash tool's
+environment has no `CLAUDE_SKILL_DIR` to expand it from.
+
+Every `run.mjs` and `setup-deps.mjs` command takes the leading `--data-dir` flag shown above.
+The Bash tool's environment does not carry this plugin's `CLAUDE_PLUGIN_DATA`, and another
+plugin's SessionStart hook can put its own data directory there under that name. The scripts
+therefore take the directory from the flag, and accept an inherited value only when it names this
+plugin. Basis: the plugins reference,
 <https://code.claude.com/docs/en/plugins-reference#where-each-variable-resolves>, verified
-2026-09-30; recheck when that table adds supporting files to where a `${…}` reference resolves.
+2026-10-02; recheck when that table adds supporting files to where a `${…}` reference resolves, or
+lists the Bash tool among the processes that receive the variables.
 
 ## Storage
 
diff --git a/plugins/knowledge/skills/course-digest/context/storage-schema.md b/plugins/knowledge/skills/course-digest/context/storage-schema.md
index 263c51bfa0..fd35031f33 100644
--- a/plugins/knowledge/skills/course-digest/context/storage-schema.md
+++ b/plugins/knowledge/skills/course-digest/context/storage-schema.md
@@ -1,6 +1,6 @@
 # Storage Schema
 
-All course data lives under the invoking project's `library_dir` setting (or `${CLAUDE_PLUGIN_DATA}` when no library dir is configured), as `courses/<platform>/<slug>/`.
+All course data lives under the invoking project's `library_dir` setting (or `<plugin-data>` when no library dir is configured), as `courses/<platform>/<slug>/`.
 
 ## Platform naming
 
diff --git a/plugins/knowledge/skills/course-digest/context/workflow.md b/plugins/knowledge/skills/course-digest/context/workflow.md
index 68d9fd3502..377d884ef2 100644
--- a/plugins/knowledge/skills/course-digest/context/workflow.md
+++ b/plugins/knowledge/skills/course-digest/context/workflow.md
@@ -79,10 +79,10 @@ Repo → Validate → THEN Synthesize.
 
 **Steps (sequential):**
 
-1. `node "<skill-dir>/extraction/run.mjs" classify-frames.js --course-dir <path> --phase contact-sheets`: generate labeled thumbnail grids
-2. `node "<skill-dir>/extraction/run.mjs" classify-frames.js --course-dir <path> --phase dedup`: near-duplicate detection
-3. `node "<skill-dir>/extraction/run.mjs" generate-manifests.js --course-dir <path>`: curate frame sets per lesson
-4. `node "<skill-dir>/extraction/run.mjs" classify-frames.js --course-dir <path> --phase summary`: print frame inventory
+1. `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" classify-frames.js --course-dir <path> --phase contact-sheets`: generate labeled thumbnail grids
+2. `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" classify-frames.js --course-dir <path> --phase dedup`: near-duplicate detection
+3. `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" generate-manifests.js --course-dir <path>`: curate frame sets per lesson
+4. `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" classify-frames.js --course-dir <path> --phase summary`: print frame inventory
 
 **Output:** Contact sheets, dedup report, manifests per lesson.
 
@@ -129,7 +129,7 @@ downloaded source code ZIPs. If neither exists, skip.
 
 **Steps (GitHub repo path):**
 
-1. `node "<skill-dir>/extraction/run.mjs" analyze-code-repo.js --course-dir <path>`: clone to temp, detect structure, write metadata
+1. `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" analyze-code-repo.js --course-dir <path>`: clone to temp, detect structure, write metadata
 2. Clone again to `code/repo/` for Phase 3 access: `git clone --depth 1 --single-branch <url> code/repo/`
 3. Review `code/analysis.json` for repo structure (per-section vs single-state)
 4. Build section-to-module mapping table: which repo sections correspond to which course modules
@@ -170,7 +170,7 @@ only, then discard.
 
 **Steps:**
 
-1. `node "<skill-dir>/extraction/run.mjs" validate-extraction.js --course-dir <path>`: run all quality checks
+1. `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" validate-extraction.js --course-dir <path>`: run all quality checks
 2. Review `validation-report.json` and fix any FAIL items before proceeding
 3. On re-runs: compare against previous `validation-report.json` for regressions
 
diff --git a/plugins/knowledge/skills/course-digest/extraction/entry-data-dir.test.js b/plugins/knowledge/skills/course-digest/extraction/entry-data-dir.test.js
new file mode 100644
index 0000000000..e4fe8a3eeb
--- /dev/null
+++ b/plugins/knowledge/skills/course-digest/extraction/entry-data-dir.test.js
@@ -0,0 +1,84 @@
+import { spawnSync } from "node:child_process";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { fileURLToPath, pathToFileURL } from "node:url";
+
+import { afterAll, describe, expect, it } from "vitest";
+
+const dir = path.dirname(fileURLToPath(import.meta.url));
+const sandboxes = [];
+afterAll(() => {
+  for (const sandbox of sandboxes) fs.rmSync(sandbox, { recursive: true, force: true });
+});
+
+/** Another plugin's data directory, empty, the way a leaked CLAUDE_PLUGIN_DATA names it. */
+function foreignDataDir() {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "course-setup-deps-"));
+  sandboxes.push(root);
+  const foreign = path.join(root, "codex-openai-codex");
+  fs.mkdirSync(foreign);
+  return foreign;
+}
+
+function run(script, args, env) {
+  return spawnSync(process.execPath, [path.join(dir, script), ...args], {
+    encoding: "utf8",
+    timeout: 20000,
+    env: { ...process.env, ...env },
+  });
+}
+
+describe("data directory resolution in the Bash-run entry points", () => {
+  it("setup-deps refuses an inherited CLAUDE_PLUGIN_DATA naming another plugin and writes nothing there", () => {
+    const foreign = foreignDataDir();
+    const result = run("setup-deps.mjs", [], { CLAUDE_PLUGIN_DATA: foreign });
+    expect(result.status).toBe(1);
+    expect(result.stderr).toContain('--data-dir "${CLAUDE_PLUGIN_DATA}"');
+    expect(fs.readdirSync(foreign)).toEqual([]);
+  });
+
+  it("setup-deps rejects an unsubstituted placeholder before creating anything", () => {
+    const foreign = foreignDataDir();
+    const result = run("setup-deps.mjs", ["--data-dir", "<plugin-data>"], { CLAUDE_PLUGIN_DATA: foreign });
+    expect(result.status).toBe(2);
+    expect(result.stderr).toContain("unsubstituted placeholder");
+    expect(fs.readdirSync(foreign)).toEqual([]);
+  });
+
+  it("run.mjs hands the child the --data-dir value, not an inherited one naming another plugin", () => {
+    const foreign = foreignDataDir();
+    const knowledge = path.join(path.dirname(foreign), "knowledge-melodic-software");
+    const dest = path.join(path.dirname(foreign), "course");
+    const stub = pathToFileURL(path.join(dir, "test-support", "register-playwright-stub.mjs")).href;
+    const result = run(
+      "run.mjs",
+      ["--data-dir", knowledge, "build-course-json.js", "--course-url", "https://example.test/courses/enrolled/1", "--output-dir", dest],
+      { CLAUDE_PLUGIN_DATA: foreign, NODE_OPTIONS: `--import ${stub}` },
+    );
+    expect(result.stderr).toContain("playwright stub: chromium.launch blocked in tests");
+    expect(fs.existsSync(path.join(knowledge, "auth"))).toBe(true);
+    expect(fs.readdirSync(foreign)).toEqual([]);
+  });
+
+  it("run.mjs drops an inherited value naming another plugin when no flag is given", () => {
+    const foreign = foreignDataDir();
+    const home = path.dirname(foreign);
+    const dest = path.join(home, "course");
+    const stub = pathToFileURL(path.join(dir, "test-support", "register-playwright-stub.mjs")).href;
+    const result = run(
+      "run.mjs",
+      ["build-course-json.js", "--course-url", "https://example.test/courses/enrolled/1", "--output-dir", dest],
+      { CLAUDE_PLUGIN_DATA: foreign, HOME: home, USERPROFILE: home, NODE_OPTIONS: `--import ${stub}` },
+    );
+    expect(result.stderr).toContain("playwright stub: chromium.launch blocked in tests");
+    expect(fs.readdirSync(foreign)).toEqual([]);
+    expect(fs.existsSync(path.join(home, ".claude", "course-digest", "auth"))).toBe(true);
+  });
+
+  it("run.mjs rejects an unsubstituted placeholder instead of launching the script", () => {
+    const result = run("run.mjs", ["--data-dir", "${CLAUDE_PLUGIN_DATA}", "validate-extraction.js"], {});
+    expect(result.status).toBe(2);
+    expect(result.stderr).toContain("unsubstituted placeholder");
+  });
+});
diff --git a/plugins/knowledge/skills/course-digest/extraction/lib/plugin-data.js b/plugins/knowledge/skills/course-digest/extraction/lib/plugin-data.js
new file mode 100644
index 0000000000..acf75683a7
--- /dev/null
+++ b/plugins/knowledge/skills/course-digest/extraction/lib/plugin-data.js
@@ -0,0 +1,46 @@
+/**
+ * The knowledge plugin's data directory for `run.mjs` and `setup-deps.mjs`, which
+ * Claude runs through the Bash tool. That tool's environment does not carry
+ * `CLAUDE_PLUGIN_DATA`, and another plugin's SessionStart hook can persist its own
+ * data directory there under that name, so the skill passes a leading
+ * `--data-dir "${CLAUDE_PLUGIN_DATA}"`, substituted when the skill loads, and that
+ * value wins. Without the flag an inherited value is used only when its last path
+ * segment names this plugin (`knowledge-<marketplace>`), the order the marketplace's
+ * on-demand-dependencies convention sets. Basis: plugins reference, "Where each
+ * variable resolves", as of 2026-10-02.
+ *
+ * Pure, so the launcher's contract is unit-testable without spawning a process.
+ */
+
+/**
+ * Split a leading `--data-dir <dir>` off the launcher's argv.
+ *
+ * @param {string[]} argv
+ * @returns {{ dataDir: string|undefined, rest: string[] }}
+ */
+export function takeDataDirFlag(argv) {
+  if (argv[0] !== "--data-dir") {
+    return { dataDir: undefined, rest: [...argv] };
+  }
+  if (argv.length < 2) {
+    throw new Error("`--data-dir` requires a directory value");
+  }
+  return { dataDir: argv[1], rest: argv.slice(2) };
+}
+
+/**
+ * @param {string|undefined} flagValue
+ * @param {NodeJS.ProcessEnv} env
+ * @returns {string|undefined} undefined when neither source names this plugin
+ */
+export function resolvePluginData(flagValue, env) {
+  if (flagValue) {
+    if (flagValue.includes("${") || flagValue.includes("<plugin-data>")) {
+      throw new Error(`\`--data-dir\` got an unsubstituted placeholder: \`${flagValue}\``);
+    }
+    return flagValue;
+  }
+  const inherited = env.CLAUDE_PLUGIN_DATA;
+  const lastSegment = inherited?.replace(/[\\/]+$/, "").split(/[\\/]/).pop() ?? "";
+  return /^knowledge(-|$)/.test(lastSegment) ? inherited : undefined;
+}
diff --git a/plugins/knowledge/skills/course-digest/extraction/lib/plugin-data.test.js b/plugins/knowledge/skills/course-digest/extraction/lib/plugin-data.test.js
new file mode 100644
index 0000000000..005e9e73a6
--- /dev/null
+++ b/plugins/knowledge/skills/course-digest/extraction/lib/plugin-data.test.js
@@ -0,0 +1,52 @@
+import { describe, expect, it } from "vitest";
+
+import { resolvePluginData, takeDataDirFlag } from "./plugin-data.js";
+
+describe("takeDataDirFlag", () => {
+  it("splits a leading --data-dir off the script and its args", () => {
+    expect(takeDataDirFlag(["--data-dir", "/d/knowledge-m", "extract-course.js", "--course-dir", "/c"])).toEqual({
+      dataDir: "/d/knowledge-m",
+      rest: ["extract-course.js", "--course-dir", "/c"],
+    });
+  });
+
+  it("leaves argv alone when the flag is not leading", () => {
+    expect(takeDataDirFlag(["extract-course.js", "--data-dir", "/d"])).toEqual({
+      dataDir: undefined,
+      rest: ["extract-course.js", "--data-dir", "/d"],
+    });
+  });
+
+  it("throws when --data-dir has no value", () => {
+    expect(() => takeDataDirFlag(["--data-dir"])).toThrow(/`--data-dir` requires a directory value/);
+  });
+});
+
+describe("resolvePluginData", () => {
+  const knowledge = "C:/fixture/claude/plugins/data/knowledge-melodic-software";
+  const codex = "C:/fixture/claude/plugins/data/codex-openai-codex";
+
+  it("prefers the flag over an inherited value naming another plugin", () => {
+    expect(resolvePluginData(knowledge, { CLAUDE_PLUGIN_DATA: codex })).toBe(knowledge);
+  });
+
+  it("ignores an inherited value naming another plugin when no flag is given", () => {
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: codex })).toBeUndefined();
+  });
+
+  it("keeps an inherited value naming this plugin when no flag is given", () => {
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: knowledge })).toBe(knowledge);
+    const windows = "C:\\fixture\\claude\\plugins\\data\\knowledge-inline\\";
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: windows })).toBe(windows);
+  });
+
+  it("does not take a prefix match for this plugin's name", () => {
+    const lookalike = "/var/fixture/claude/plugins/data/knowledgebase-other";
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: lookalike })).toBeUndefined();
+  });
+
+  it("throws on a placeholder that reached the script unsubstituted", () => {
+    expect(() => resolvePluginData("${CLAUDE_PLUGIN_DATA}", {})).toThrow(/unsubstituted placeholder/);
+    expect(() => resolvePluginData("<plugin-data>", {})).toThrow(/unsubstituted placeholder/);
+  });
+});
diff --git a/plugins/knowledge/skills/course-digest/extraction/run.mjs b/plugins/knowledge/skills/course-digest/extraction/run.mjs
index 4861899b93..23e0559816 100755
--- a/plugins/knowledge/skills/course-digest/extraction/run.mjs
+++ b/plugins/knowledge/skills/course-digest/extraction/run.mjs
@@ -18,17 +18,35 @@
  * path in lockstep. An explicit value already in the environment wins (honored,
  * not overwritten).
  *
- * Usage: node run.mjs <relative-script.js> [args…]
+ * The leading `--data-dir` names the data directory (`lib/plugin-data.js`). The child
+ * sees only the value `resolvePluginData` accepts, never an inherited
+ * `CLAUDE_PLUGIN_DATA` that names another plugin.
+ *
+ * Usage: node run.mjs [--data-dir <dir>] <relative-script.js> [args…]
  */
 import { spawnSync } from "node:child_process";
 import path from "node:path";
 import { fileURLToPath, pathToFileURL } from "node:url";
 
+import { resolvePluginData, takeDataDirFlag } from "./lib/plugin-data.js";
+
 const here = path.dirname(fileURLToPath(import.meta.url));
-const [script, ...rest] = process.argv.slice(2);
+const usage = "Usage: node run.mjs [--data-dir <dir>] <relative-script.js> [args…]\n";
+
+let dataDir;
+let script;
+let rest;
+try {
+  const taken = takeDataDirFlag(process.argv.slice(2));
+  [script, ...rest] = taken.rest;
+  dataDir = resolvePluginData(taken.dataDir, process.env);
+} catch (error) {
+  process.stderr.write(`${error.message}\n${usage}`);
+  process.exit(2);
+}
 
 if (!script) {
-  process.stderr.write("Usage: node run.mjs <relative-script.js> [args…]\n");
+  process.stderr.write(usage);
   process.exit(2);
 }
 
@@ -39,9 +57,10 @@ if (rel.startsWith("..") || path.isAbsolute(rel)) {
   process.exit(2);
 }
 
-const env = { ...process.env };
-if (!env.PLAYWRIGHT_BROWSERS_PATH && env.CLAUDE_PLUGIN_DATA) {
-  env.PLAYWRIGHT_BROWSERS_PATH = path.join(env.CLAUDE_PLUGIN_DATA, "ms-playwright");
+const { CLAUDE_PLUGIN_DATA: _inherited, ...env } = process.env;
+if (dataDir) {
+  env.CLAUDE_PLUGIN_DATA = dataDir;
+  env.PLAYWRIGHT_BROWSERS_PATH ||= path.join(dataDir, "ms-playwright");
 }
 
 const registerHook = path.join(here, "register-hook.mjs");
diff --git a/plugins/knowledge/skills/course-digest/extraction/setup-deps.mjs b/plugins/knowledge/skills/course-digest/extraction/setup-deps.mjs
index 560678fbf7..8bdc2368bf 100755
--- a/plugins/knowledge/skills/course-digest/extraction/setup-deps.mjs
+++ b/plugins/knowledge/skills/course-digest/extraction/setup-deps.mjs
@@ -21,7 +21,10 @@
  * directory (the same value run.mjs sets at launch) keeps install path and
  * runtime lookup path in lockstep.
  *
- * Usage: node setup-deps.mjs
+ * The data directory comes from `--data-dir`, resolved like `run.mjs` resolves it
+ * (`lib/plugin-data.js`), and nothing is written until it resolves.
+ *
+ * Usage: node setup-deps.mjs --data-dir <dir>
  */
 import { spawnSync } from "node:child_process";
 import { createHash } from "node:crypto";
@@ -29,12 +32,27 @@ import fs from "node:fs";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
 
+import { resolvePluginData, takeDataDirFlag } from "./lib/plugin-data.js";
+
 const here = path.dirname(fileURLToPath(import.meta.url));
-const data = process.env.CLAUDE_PLUGIN_DATA;
+const usage = "Usage: node setup-deps.mjs --data-dir <dir>\n";
+
+let data;
+try {
+  const { dataDir, rest } = takeDataDirFlag(process.argv.slice(2));
+  if (rest.length > 0) {
+    throw new Error("setup-deps.mjs takes only `--data-dir <dir>`");
+  }
+  data = resolvePluginData(dataDir, process.env);
+} catch (error) {
+  process.stderr.write(`${error.message}\n${usage}`);
+  process.exit(2);
+}
 
 if (!data) {
   process.stderr.write(
-    "CLAUDE_PLUGIN_DATA is not set. Run this inside Claude Code with the knowledge plugin installed.\n",
+    'The knowledge plugin data directory is unknown. Pass --data-dir "${CLAUDE_PLUGIN_DATA}" from the skill; ' +
+      "an inherited CLAUDE_PLUGIN_DATA that names another plugin is ignored.\n",
   );
   process.exit(1);
 }
diff --git a/plugins/knowledge/skills/setup/SKILL.md b/plugins/knowledge/skills/setup/SKILL.md
index 44a4b6dfe2..9d5aaf60ef 100644
--- a/plugins/knowledge/skills/setup/SKILL.md
+++ b/plugins/knowledge/skills/setup/SKILL.md
@@ -84,8 +84,8 @@ reports "already configured".
    `${CLAUDE_PLUGIN_DATA}/ms-playwright`):
 
    ```bash
-   node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/setup-deps.mjs"
-   node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/setup-deps.mjs"
+   node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/setup-deps.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}"
+   node "${CLAUDE_PLUGIN_ROOT}/skills/course-digest/extraction/setup-deps.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}"
    ```
 
    A stored fingerprint gates reinstalls, so re-running is safe and cheap. After provisioning,
diff --git a/plugins/knowledge/skills/video-digest/SKILL.md b/plugins/knowledge/skills/video-digest/SKILL.md
index db7ee01dc2..6111beb78b 100644
--- a/plugins/knowledge/skills/video-digest/SKILL.md
+++ b/plugins/knowledge/skills/video-digest/SKILL.md
@@ -11,7 +11,7 @@ shell: bash
 ## Pre-computed context
 
 ```!
-{ printf 'video-extraction deps: '; node -e "const fs=require('fs'),path=require('path'),p=process.env.CLAUDE_PLUGIN_DATA;console.log(p&&fs.existsSync(path.join(p,'node_modules','@melodic','video-digestion'))?'installed':'MISSING - run setup-deps.mjs (see Prerequisites)')" 2>/dev/null || echo "MISSING - node not found (see Prerequisites)"; }
+{ printf 'video-extraction deps: '; node -e "const fs=require('fs'),path=require('path'),p=process.argv[1];console.log(p&&fs.existsSync(path.join(p,'node_modules','@melodic','video-digestion'))?'installed':'MISSING - run setup-deps.mjs (see Prerequisites)')" "${CLAUDE_PLUGIN_DATA}" 2>/dev/null || echo "MISSING - node not found (see Prerequisites)"; }
 { printf 'yt-dlp: '; command -v yt-dlp >/dev/null 2>&1 && { yt-dlp --version 2>/dev/null | head -1; :; } || echo "MISSING — install yt-dlp (see Prerequisites)"; }
 { printf 'ffmpeg: '; command -v ffmpeg >/dev/null 2>&1 && { ffmpeg -version 2>/dev/null | head -1; :; } || echo "MISSING — install ffmpeg (watch action only)"; }
 { printf 'ImageMagick: '; command -v magick >/dev/null 2>&1 && { magick -version 2>/dev/null | head -1; :; } || echo "MISSING — install ImageMagick 7 (watch action only)"; }
@@ -80,7 +80,7 @@ own). Resolution rungs in `context/watch-pipeline.md`.
 ## Transcript action
 
 ```bash
-node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" transcript/run-transcript.js "<url>"
+node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" transcript/run-transcript.js "<url>"
 ```
 
 1. **Acquire**. Captions + info JSON (`--skip-download`)
@@ -106,8 +106,8 @@ release, FIFO, stale reclaim, parallel terminals, companion briefs, is in `conte
 read it for any queue action. Template: `templates/queue.md`.
 
 ```bash
-node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" acquisition/preflight-metadata.js "<url>" ["<url>"...]
-node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" watch/queue-claim.js {list|claim <n>|release <n>|stale-check}
+node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" acquisition/preflight-metadata.js "<url>" ["<url>"...]
+node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" watch/queue-claim.js {list|claim <n>|release <n>|stale-check}
 ```
 
 ## Watch action
@@ -124,7 +124,7 @@ Ordered phase spine. Each phase's procedure, inputs, and outputs: `context/watch
    harvest):
 
    ```bash
-   node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" watch/run-watch.js "<url>" [--skip-research] [--target <repo>] [--max-frame-gap-sec <sec>]
+   node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" watch/run-watch.js "<url>" [--skip-research] [--target <repo>] [--max-frame-gap-sec <sec>]
    ```
 
    `--max-frame-gap-sec` sets the longest stretch between timed frames before a gap-fill frame is
@@ -162,7 +162,7 @@ it carries depends on which 0-case it is. See `reference/sources/x.md`.
 ## Resume action
 
 ```bash
-node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" watch/run-resume.js "<slice-slug>"
+node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}" watch/run-resume.js "<slice-slug>"
 ```
 
 Reads the slice `watch.json`, identifies the next incomplete phase (`acquire` → `transcript` →
@@ -191,13 +191,21 @@ before writing or staging slice artifacts.
 
 ## Spoke paths
 
-The `context/` and `reference/` files write this skill's directory as `<skill-dir>`, which is
-`${CLAUDE_SKILL_DIR}`. Put that path in place of the placeholder before running a command or
+The `context/`, `reference/` and `templates/` files write this skill's directory as `<skill-dir>`,
+which is `${CLAUDE_SKILL_DIR}`, and the plugin data directory as `<plugin-data>`, which is
+`${CLAUDE_PLUGIN_DATA}`. Put those paths in place of the placeholders before running a command or
 writing it into a brief. Those files arrive through the Read tool as plain bytes, so a `${…}` token
 in them would reach the Bash tool unsubstituted, and the Bash tool's environment has no
-`CLAUDE_SKILL_DIR` to expand it from. Basis: the plugins reference,
+`CLAUDE_SKILL_DIR` to expand it from.
+
+Every `run.mjs` and `setup-deps.mjs` command takes the leading `--data-dir` flag shown above.
+The Bash tool's environment does not carry this plugin's `CLAUDE_PLUGIN_DATA`, and another
+plugin's SessionStart hook can put its own data directory there under that name. The scripts
+therefore take the directory from the flag, and accept an inherited value only when it names this
+plugin. Basis: the plugins reference,
 <https://code.claude.com/docs/en/plugins-reference#where-each-variable-resolves>, verified
-2026-09-30; recheck when that table adds supporting files to where a `${…}` reference resolves.
+2026-10-02; recheck when that table adds supporting files to where a `${…}` reference resolves, or
+lists the Bash tool among the processes that receive the variables.
 
 ## Gotchas
 
@@ -210,7 +218,7 @@ patterns live in the source spokes.
 
 Verify before starting (stop and route to the fix path on failure):
 
-1. **video-extraction deps**. `node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/setup-deps.mjs"`.
+1. **video-extraction deps**. `node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/setup-deps.mjs" --data-dir "${CLAUDE_PLUGIN_DATA}"`.
    Installs the pipeline's node dependencies into `${CLAUDE_PLUGIN_DATA}` (persists across plugin
    updates); idempotent. Safe to re-run, and re-run after a plugin update.
 2. **yt-dlp**, required for all actions. Floor **2026.6**. Install: `winget install yt-dlp.yt-dlp`
diff --git a/plugins/knowledge/skills/video-digest/context/output-contract.md b/plugins/knowledge/skills/video-digest/context/output-contract.md
index 206355d62f..988b6fa439 100644
--- a/plugins/knowledge/skills/video-digest/context/output-contract.md
+++ b/plugins/knowledge/skills/video-digest/context/output-contract.md
@@ -21,7 +21,7 @@ this skill's content as `${user_config.library_dir}`:
   **leading** `--work-root` flag on **every** `run.mjs` invocation in this skill:
 
   ```bash
-  node "<skill-dir>/extraction/run.mjs" --work-root "${CLAUDE_PROJECT_DIR}/${user_config.library_dir}" <script.js> [args…]
+  node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" --work-root "${CLAUDE_PROJECT_DIR}/${user_config.library_dir}" <script.js> [args…]
   ```
 
   `run.mjs` forwards it to the extraction child as an environment variable (a double-quoted CLI
@@ -45,8 +45,8 @@ this skill's content as `${user_config.library_dir}`:
   token, invoke `run.mjs` **without** `--work-root`. `resolveWorkRoot()` falls back to
   `${CLAUDE_PROJECT_DIR}` (then `process.cwd()`), landing artifacts at the consuming repo root.
 
-The `setup-deps.mjs` install step is exempt. It installs node dependencies into
-`${CLAUDE_PLUGIN_DATA}`, not the work root.
+The `setup-deps.mjs` install step takes no `--work-root`. It installs node dependencies into the
+plugin data directory its `--data-dir "<plugin-data>"` flag names, not the work root.
 
 `run.mjs` translates `--work-root` into `VIDEO_DIGEST_WORK_ROOT`, the variable
 `resolveWorkRoot()` reads before the fallbacks above. Every extraction variable lives in that
diff --git a/plugins/knowledge/skills/video-digest/context/quality-gates.md b/plugins/knowledge/skills/video-digest/context/quality-gates.md
index 8c0cea7cb4..6d0a77c4ce 100644
--- a/plugins/knowledge/skills/video-digest/context/quality-gates.md
+++ b/plugins/knowledge/skills/video-digest/context/quality-gates.md
@@ -50,7 +50,7 @@ This table lists the **blocking artifacts per phase** (which must exist before t
 
 ## Outcome verification (host verify script)
 
-`node "<skill-dir>/extraction/run.mjs" evals/check-watch-outcomes.js "<slice-dir>" --write-report`
+`node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" evals/check-watch-outcomes.js "<slice-dir>" --write-report`
 
 | ID | Binary criterion | FAIL → |
 | --- | --- | --- |
@@ -84,7 +84,7 @@ Host verify scripts prove **traceability and shape** (JSON valid, batch files on
 
 ## Research gate (host verify script)
 
-`node "<skill-dir>/extraction/run.mjs" evals/check-research-complete.js "<slice-dir>"`
+`node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" evals/check-research-complete.js "<slice-dir>"`
 
 | Criterion | FAIL → |
 | --- | --- |
diff --git a/plugins/knowledge/skills/video-digest/context/watch-pipeline.md b/plugins/knowledge/skills/video-digest/context/watch-pipeline.md
index 6ebe024b45..73327f80a1 100644
--- a/plugins/knowledge/skills/video-digest/context/watch-pipeline.md
+++ b/plugins/knowledge/skills/video-digest/context/watch-pipeline.md
@@ -36,7 +36,7 @@ On resume: if companion is unmarked, run 0b before vision even when CLI phases a
 ## CLI bootstrap
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/run-watch.js "<url>" [--skip-research] [--target <repo>] [--max-frame-gap-sec <sec>]
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/run-watch.js "<url>" [--skip-research] [--target <repo>] [--max-frame-gap-sec <sec>]
 ```
 
 Pass an explicit `--target <repo>` through from the invoking `watch <url> --target <repo>` command.
@@ -68,7 +68,7 @@ snapshotted to `key-frames/contact-sheets/` for local disaster recovery, see
 Before `watch` or `resume` when frames are needed:
 
 ```bash
-node "<skill-dir>/extraction/setup-deps.mjs"
+node "<skill-dir>/extraction/setup-deps.mjs" --data-dir "<plugin-data>"
 ```
 
 STOP if the hub's pre-computed context shows MISSING for yt-dlp, ffmpeg, or ImageMagick. Cloud
@@ -82,7 +82,7 @@ After CLI bootstrap, parallelize like `/knowledge:course-digest` Phase 3:
 | --- | --- | --- |
 | Parallel | Transcript agent | Claims + timestamps → `research/research-agenda.md` draft |
 | Parallel | Visual agent | Contact-sheet triage → detail reads → `key-frames/visual-frames.md` + on-screen URLs |
-| Parallel | Link/repo agent | WebFetch previews + `node "<skill-dir>/extraction/run.mjs" harvesting/analyze-harvested-repos.js <slice-dir>` when GitHub links exist |
+| Parallel | Link/repo agent | WebFetch previews + `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" harvesting/analyze-harvested-repos.js <slice-dir>` when GitHub links exist |
 | Sequential | Research fan-out | external research (standard or deep) per claim cluster → `RESEARCH.md` + `research/findings/` |
 | Sequential | Synthesis agent | `recommendations/menu.md` + `recommendations/takeaways.md` (hub: `recommendations/README.md`) |
 | Sequential | Interview handoff | `recommendations/interview.md` → offer `/planning:interview` for POC/full-slice picks |
@@ -91,7 +91,7 @@ Mark each phase in `watch.json` after the wave completes (idempotent, re-running
 already-marked phase is a no-op):
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/watch-state.js mark-phase <slice-dir> <phase>
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/watch-state.js mark-phase <slice-dir> <phase>
 ```
 
 `mark-phase <slice-dir> synthesis` delegates to `close` (Phase 9).
@@ -99,7 +99,7 @@ node "<skill-dir>/extraction/run.mjs" watch/watch-state.js mark-phase <slice-dir
 Promote only via vision-gated decisions:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/vision-gated-promote.js "<slice-dir>"
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/vision-gated-promote.js "<slice-dir>"
 ```
 
 (`promote-key-frames.js` remains for ad-hoc single copies, not the completion path.)
@@ -109,7 +109,7 @@ node "<skill-dir>/extraction/run.mjs" watch/vision-gated-promote.js "<slice-dir>
 After CLI bootstrap (or on resume), materialize and maintain the slice checklist:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/init-watch-checklist.js "<slice-dir>"
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/init-watch-checklist.js "<slice-dir>"
 ```
 
 Use `--force` to regenerate per-sheet rows after `contactSheetCount` changes. Tick `[ ]` → `[x]`
@@ -164,7 +164,7 @@ Checklist: `watching/frame-triage-checklist.json`; **JSON SSOT** + rendered mark
 - **Pass 1 contact-sheet triage:** One subagent per sheet from `tempSession.contactSheetsDir`
   (or `key-frames/contact-sheets/`). Write `key-frames/triage/batches/sheet_NNN.json` (cells per
   `sheet-frame-index.json`). Merge:
-  `node "<skill-dir>/extraction/run.mjs" watch/merge-triage-json.js "<slice>"`;
+  `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/merge-triage-json.js "<slice>"`;
   validate: `validate-triage-json.js`; render: `render-triage-log.js`.
 - **Pass 2 detail reads:** All `keep-detail` frames + transcript interleave
   (`key-frames/selection.json` timeline). Escalate text-dense frames to **1920×1080**.
@@ -181,7 +181,7 @@ Checklist: `watching/frame-triage-checklist.json`; **JSON SSOT** + rendered mark
   `render-quality-audit.js` + `render-key-frames-manifest.js`. **Delete** failures with
   `pass: false`.
 - **Repair pass (when filename verify fails):**
-  `node "<skill-dir>/extraction/run.mjs" watch/repair-synthesis-promotions.js "<slice-dir>"`
+  `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/repair-synthesis-promotions.js "<slice-dir>"`
   Semantic renames from `gapNote`, reject generic pipeline placeholders, fix forbidden sessions.
 
 ## Phase 5: high-volume advisory
@@ -203,7 +203,7 @@ Default-on. Gate: `mark-phase <slice-dir> research` only after `check-research-c
 and agenda clusters are `done` or `deferred`:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" evals/check-research-complete.js "<slice-dir>"
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" evals/check-research-complete.js "<slice-dir>"
 ```
 
 - `research/claim-inventory.md` must exist; draft or expand `research/research-agenda.md` with
@@ -282,14 +282,14 @@ Write `recommendations/interview.md` with the menu + *"Should we go further?"*;
 Mandatory host verify script, before closing the slice:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" evals/check-watch-outcomes.js "<slice-dir>" --write-report
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" evals/check-watch-outcomes.js "<slice-dir>" --write-report
 ```
 
 Writes `verification/<ISO-basic>Z-watch-outcomes.md`. Once it exits 0 and the blocking checklist
 items (8.1-8.4, 9.1, 9.2, 9.4) are ticked, close the slice:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/watch-state.js close "<slice-dir>"
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/watch-state.js close "<slice-dir>"
 ```
 
 `close` is the only writer of `status: complete`. It marks synthesis, re-runs the outcome checks
@@ -339,13 +339,13 @@ correction. A probe on ffmpeg 8.0.1 found the reported times already relative to
 Standalone pipeline (when video + VTT already acquired):
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watching/run-watching-pipeline.js "<video-path>" "<vtt-path>"
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watching/run-watching-pipeline.js "<video-path>" "<vtt-path>"
 ```
 
 Metadata-only link harvest:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" harvesting/run-harvest.js "<info-json-path>" [--url "<source-url>"]
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" harvesting/run-harvest.js "<info-json-path>" [--url "<source-url>"]
 ```
 
 The owning source adapter is resolved from `--url` when given, else from the info JSON's
diff --git a/plugins/knowledge/skills/video-digest/context/watch-queue.md b/plugins/knowledge/skills/video-digest/context/watch-queue.md
index ba5c35a30c..0d1f2fe07d 100644
--- a/plugins/knowledge/skills/video-digest/context/watch-queue.md
+++ b/plugins/knowledge/skills/video-digest/context/watch-queue.md
@@ -59,7 +59,7 @@ Claim metadata (`claimedAt`, `claimedBy`) lives in `claims/<n>.json`, not in the
 1. Run exclusive claim (skill or CLI):
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/queue-claim.js claim <n> [--video-id <id>]
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/queue-claim.js claim <n> [--video-id <id>]
 ```
 
 Exit code `2` = row already taken. For FIFO `watch`, try the next `pending` row; for `watch <n>`, stop with a clear message rather than bootstrapping duplicate work.
@@ -68,7 +68,7 @@ Exit code `2` = row already taken. For FIFO `watch`, try the next `pending` row;
 2. Read URL from row; bootstrap:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/run-watch.js "<url>"
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/run-watch.js "<url>"
 ```
 
 1. Execute skill phases 2–9 (or `run-resume.js` if slice exists and temp valid).
@@ -76,7 +76,7 @@ node "<skill-dir>/extraction/run.mjs" watch/run-watch.js "<url>"
 3. Release claim:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/queue-claim.js release <n>
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/queue-claim.js release <n>
 ```
 
 ### FIFO auto-dequeue (`watch` with no URL)
@@ -99,7 +99,7 @@ Scan rows in `#` order. For each `pending` row, attempt `claim <n>`. On `EEXIST`
 If `claims/<n>.json` exists and `claimedAt` is older than **7 days**, skill may:
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" watch/queue-claim.js stale-check
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" watch/queue-claim.js stale-check
 ```
 
 Then reset row `#n` from `in_progress` → `pending` and delete the stub (abandoned run).
@@ -144,7 +144,7 @@ When the operator supplies companion URL(s) with queue intent, record them befor
 Before appending rows, validate each URL and fetch its title + channel through the same auth-fallback path acquisition uses (a bot-checked video that `watch` could acquire with cookies is NOT rejected at queue time):
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" acquisition/preflight-metadata.js "<url>" ["<url>"...]
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" acquisition/preflight-metadata.js "<url>" ["<url>"...]
 ```
 
 Emits a JSON array (one entry per URL). Per entry use `action` to decide:
diff --git a/plugins/knowledge/skills/video-digest/extraction/lib/run-args.js b/plugins/knowledge/skills/video-digest/extraction/lib/run-args.js
index 4f18b13344..1f266d9e42 100644
--- a/plugins/knowledge/skills/video-digest/extraction/lib/run-args.js
+++ b/plugins/knowledge/skills/video-digest/extraction/lib/run-args.js
@@ -8,6 +8,7 @@
  * option is passed as a cross-platform double-quoted CLI arg and translated here
  * into the environment variable the extraction child already reads. The env vars
  * are an internal launcher-to-child interface, not a consumer-facing channel.
+ * `--data-dir` carries the plugin data directory the same way (see `resolvePluginData`).
  *
  * Both helpers are pure so the launcher's contract is unit-testable without
  * spawning a child process.
@@ -19,6 +20,7 @@
  * missing-value error message.
  */
 const LEADING_FLAGS = {
+  "--data-dir": { key: "dataDir", env: "CLAUDE_PLUGIN_DATA", valueLabel: "directory value" },
   "--work-root": { key: "workRoot", env: "VIDEO_DIGEST_WORK_ROOT", valueLabel: "directory value" },
   "--js-runtimes": {
     key: "jsRuntimes",
@@ -49,6 +51,7 @@ const LEADING_FLAGS = {
 
 /**
  * @typedef {object} RunArgs
+ * @property {string} [dataDir]
  * @property {string} [workRoot]
  * @property {string} [jsRuntimes]
  * @property {string} [cookiesFile]
@@ -112,6 +115,33 @@ export function buildChildEnv(baseEnv, flags = {}) {
   return { ...baseEnv, ...overlay };
 }
 
+/**
+ * The knowledge plugin's data directory for a script Claude runs through the Bash tool.
+ *
+ * That tool's environment does not carry `CLAUDE_PLUGIN_DATA`, and another plugin's
+ * SessionStart hook can persist its own data directory there under that name, so the
+ * skill passes `--data-dir "${CLAUDE_PLUGIN_DATA}"`, substituted when the skill loads,
+ * and that value wins. Without the flag an inherited value is used only when its last
+ * path segment names this plugin (`knowledge-<marketplace>`), the order the
+ * marketplace's on-demand-dependencies convention sets. Basis: plugins reference,
+ * "Where each variable resolves", as of 2026-10-02.
+ *
+ * @param {string|undefined} flagValue
+ * @param {NodeJS.ProcessEnv} env
+ * @returns {string|undefined} undefined when neither source names this plugin
+ */
+export function resolvePluginData(flagValue, env) {
+  if (flagValue) {
+    if (flagValue.includes("${") || flagValue.includes("<plugin-data>")) {
+      throw new Error(`\`--data-dir\` got an unsubstituted placeholder: \`${flagValue}\``);
+    }
+    return flagValue;
+  }
+  const inherited = env.CLAUDE_PLUGIN_DATA;
+  const lastSegment = inherited?.replace(/[\\/]+$/, "").split(/[\\/]/).pop() ?? "";
+  return /^knowledge(-|$)/.test(lastSegment) ? inherited : undefined;
+}
+
 const ENV_REF = /\$\{([A-Za-z_][A-Za-z0-9_]*)\}|%([A-Za-z_][A-Za-z0-9_]*)%/g;
 
 /**
diff --git a/plugins/knowledge/skills/video-digest/extraction/lib/run-args.test.js b/plugins/knowledge/skills/video-digest/extraction/lib/run-args.test.js
index b24e825023..ab7958e29e 100644
--- a/plugins/knowledge/skills/video-digest/extraction/lib/run-args.test.js
+++ b/plugins/knowledge/skills/video-digest/extraction/lib/run-args.test.js
@@ -1,6 +1,6 @@
 import { describe, expect, it } from "vitest";
 
-import { buildChildEnv, expandPathValue, parseRunArgs } from "./run-args.js";
+import { buildChildEnv, expandPathValue, parseRunArgs, resolvePluginData } from "./run-args.js";
 
 describe("parseRunArgs", () => {
   it("returns no flags when none are present", () => {
@@ -55,6 +55,21 @@ describe("parseRunArgs", () => {
     expect(parsed.rest).toEqual(["--work-root", "list"]);
   });
 
+  it("extracts --data-dir alongside --work-root in either order", () => {
+    const data = "/var/fixture/claude/plugins/data/knowledge-melodic-software";
+    const expected = { dataDir: data, workRoot: "/proj", script: "watch/run-watch.js", rest: ["https://x"] };
+    expect(parseRunArgs(["--data-dir", data, "--work-root", "/proj", "watch/run-watch.js", "https://x"])).toEqual(
+      expected,
+    );
+    expect(parseRunArgs(["--work-root", "/proj", "--data-dir", data, "watch/run-watch.js", "https://x"])).toEqual(
+      expected,
+    );
+  });
+
+  it("throws when --data-dir has no value", () => {
+    expect(() => parseRunArgs(["--data-dir"])).toThrow(/`--data-dir` requires a directory value/);
+  });
+
   it("throws when --work-root has no value", () => {
     expect(() => parseRunArgs(["--work-root"])).toThrow(/requires a directory value/);
   });
@@ -112,6 +127,48 @@ describe("buildChildEnv", () => {
     buildChildEnv(base, { workRoot: "/proj" });
     expect(base).toEqual({ PATH: "/usr/bin" });
   });
+
+  it("hands the child the data dir as CLAUDE_PLUGIN_DATA", () => {
+    expect(buildChildEnv({ PATH: "/usr/bin" }, { dataDir: "/data/knowledge-m" })).toEqual({
+      PATH: "/usr/bin",
+      CLAUDE_PLUGIN_DATA: "/data/knowledge-m",
+    });
+  });
+});
+
+describe("resolvePluginData", () => {
+  const knowledge = "C:/fixture/claude/plugins/data/knowledge-melodic-software";
+  const codex = "C:/fixture/claude/plugins/data/codex-openai-codex";
+
+  it("prefers the flag over an inherited value naming another plugin", () => {
+    expect(resolvePluginData(knowledge, { CLAUDE_PLUGIN_DATA: codex })).toBe(knowledge);
+  });
+
+  it("ignores an inherited value naming another plugin when no flag is given", () => {
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: codex })).toBeUndefined();
+    expect(resolvePluginData("", { CLAUDE_PLUGIN_DATA: codex })).toBeUndefined();
+  });
+
+  it("keeps an inherited value naming this plugin when no flag is given", () => {
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: knowledge })).toBe(knowledge);
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: `${knowledge}/` })).toBe(`${knowledge}/`);
+    const windows = "C:\\fixture\\claude\\plugins\\data\\knowledge-inline";
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: windows })).toBe(windows);
+  });
+
+  it("does not take a prefix match for this plugin's name", () => {
+    const lookalike = "/var/fixture/claude/plugins/data/knowledgebase-other";
+    expect(resolvePluginData(undefined, { CLAUDE_PLUGIN_DATA: lookalike })).toBeUndefined();
+  });
+
+  it("returns undefined when nothing is set", () => {
+    expect(resolvePluginData(undefined, {})).toBeUndefined();
+  });
+
+  it("throws on a placeholder that reached the script unsubstituted", () => {
+    expect(() => resolvePluginData("${CLAUDE_PLUGIN_DATA}", {})).toThrow(/unsubstituted placeholder/);
+    expect(() => resolvePluginData("<plugin-data>", {})).toThrow(/unsubstituted placeholder/);
+  });
 });
 
 describe("expandPathValue", () => {
diff --git a/plugins/knowledge/skills/video-digest/extraction/run.mjs b/plugins/knowledge/skills/video-digest/extraction/run.mjs
index 1bc3406301..a64428b99f 100755
--- a/plugins/knowledge/skills/video-digest/extraction/run.mjs
+++ b/plugins/knowledge/skills/video-digest/extraction/run.mjs
@@ -21,8 +21,12 @@
  * or `${NAME}` / `%NAME%` env-var references — expanded here (`expandPathValue`)
  * so machine-varying roots never require a literal path in stored configuration.
  *
- * Usage: node run.mjs [--work-root <dir>] [--js-runtimes <v>] [--cookies-file <path>]
- *   [--cookies-from-browser <name>] [--max-concurrent-acquires <n>]
+ * `--data-dir` names the plugin data directory the hook resolves dependencies from.
+ * The child sees only the value `resolvePluginData` accepts, never an inherited
+ * `CLAUDE_PLUGIN_DATA` that names another plugin.
+ *
+ * Usage: node run.mjs [--data-dir <dir>] [--work-root <dir>] [--js-runtimes <v>]
+ *   [--cookies-file <path>] [--cookies-from-browser <name>] [--max-concurrent-acquires <n>]
  *   [--acquire-phase-gap <sec>] <relative-script.js> [args…]
  */
 import { spawnSync } from "node:child_process";
@@ -30,18 +34,19 @@ import os from "node:os";
 import path from "node:path";
 import { pathToFileURL } from "node:url";
 
-import { buildChildEnv, expandPathValue, parseRunArgs } from "./lib/run-args.js";
+import { buildChildEnv, expandPathValue, parseRunArgs, resolvePluginData } from "./lib/run-args.js";
 
 const here = import.meta.dirname;
 
 let parsed;
 const usage =
-  "Usage: node run.mjs [--work-root <dir>] [--js-runtimes <v>] [--cookies-file <path>] " +
+  "Usage: node run.mjs [--data-dir <dir>] [--work-root <dir>] [--js-runtimes <v>] [--cookies-file <path>] " +
   "[--cookies-from-browser <name>] [--max-concurrent-acquires <n>] " +
   "[--acquire-phase-gap <sec>] <relative-script.js> [args…]\n";
 
 try {
   parsed = parseRunArgs(process.argv.slice(2));
+  parsed.dataDir = resolvePluginData(parsed.dataDir, process.env);
   if (parsed.workRoot) {
     parsed.workRoot = expandPathValue(parsed.workRoot, process.env, os.homedir());
   }
@@ -63,10 +68,11 @@ if (rel.startsWith("..") || path.isAbsolute(rel)) {
   process.exit(2);
 }
 
+const { CLAUDE_PLUGIN_DATA: _inherited, ...inheritedEnv } = process.env;
 const registerHook = path.join(here, "register-hook.mjs");
 const result = spawnSync(
   process.execPath,
   ["--import", pathToFileURL(registerHook).href, target, ...rest],
-  { stdio: "inherit", env: buildChildEnv(process.env, parsed) },
+  { stdio: "inherit", env: buildChildEnv(inheritedEnv, parsed) },
 );
 process.exit(result.status ?? 1);
diff --git a/plugins/knowledge/skills/video-digest/extraction/setup-deps.mjs b/plugins/knowledge/skills/video-digest/extraction/setup-deps.mjs
index e66f3b9ea6..ea749ac370 100755
--- a/plugins/knowledge/skills/video-digest/extraction/setup-deps.mjs
+++ b/plugins/knowledge/skills/video-digest/extraction/setup-deps.mjs
@@ -14,19 +14,37 @@
  * real installs so they resolve from the data directory rather than a symlink
  * back into the plugin cache.
  *
- * Usage: node setup-deps.mjs
+ * The data directory comes from `--data-dir`, resolved like `run.mjs` resolves it
+ * (`resolvePluginData`), and nothing is written until it resolves.
+ *
+ * Usage: node setup-deps.mjs --data-dir <dir>
  */
 import { spawnSync } from "node:child_process";
 import { createHash } from "node:crypto";
 import fs from "node:fs";
 import path from "node:path";
 
+import { parseRunArgs, resolvePluginData } from "./lib/run-args.js";
+
 const here = import.meta.dirname;
-const data = process.env.CLAUDE_PLUGIN_DATA;
+const usage = "Usage: node setup-deps.mjs --data-dir <dir>\n";
+
+let data;
+try {
+  const { dataDir, script, rest: _rest, ...otherFlags } = parseRunArgs(process.argv.slice(2));
+  if (script !== undefined || Object.keys(otherFlags).length > 0) {
+    throw new Error("setup-deps.mjs takes only `--data-dir <dir>`");
+  }
+  data = resolvePluginData(dataDir, process.env);
+} catch (error) {
+  process.stderr.write(`${error.message}\n${usage}`);
+  process.exit(2);
+}
 
 if (!data) {
   process.stderr.write(
-    "CLAUDE_PLUGIN_DATA is not set. Run this inside Claude Code with the knowledge plugin installed.\n",
+    'The knowledge plugin data directory is unknown. Pass --data-dir "${CLAUDE_PLUGIN_DATA}" from the skill; ' +
+      "an inherited CLAUDE_PLUGIN_DATA that names another plugin is ignored.\n",
   );
   process.exit(1);
 }
diff --git a/plugins/knowledge/skills/video-digest/extraction/setup-deps.test.js b/plugins/knowledge/skills/video-digest/extraction/setup-deps.test.js
new file mode 100644
index 0000000000..3bdb38e558
--- /dev/null
+++ b/plugins/knowledge/skills/video-digest/extraction/setup-deps.test.js
@@ -0,0 +1,53 @@
+import { spawnSync } from "node:child_process";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+import { afterAll, describe, expect, it } from "vitest";
+
+const setupDeps = path.join(import.meta.dirname, "setup-deps.mjs");
+const sandboxes = [];
+afterAll(() => {
+  for (const dir of sandboxes) fs.rmSync(dir, { recursive: true, force: true });
+});
+
+/** Another plugin's data directory, empty, the way a leaked CLAUDE_PLUGIN_DATA names it. */
+function foreignDataDir() {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), "setup-deps-"));
+  sandboxes.push(root);
+  const dir = path.join(root, "codex-openai-codex");
+  fs.mkdirSync(dir);
+  return dir;
+}
+
+function runSetupDeps(args, env) {
+  return spawnSync(process.execPath, [setupDeps, ...args], {
+    encoding: "utf8",
+    timeout: 20000,
+    env: { ...process.env, ...env },
+  });
+}
+
+describe("setup-deps.mjs data directory", () => {
+  it("refuses an inherited CLAUDE_PLUGIN_DATA that names another plugin and writes nothing there", () => {
+    const foreign = foreignDataDir();
+    const result = runSetupDeps([], { CLAUDE_PLUGIN_DATA: foreign });
+    expect(result.status).toBe(1);
+    expect(result.stderr).toContain('--data-dir "${CLAUDE_PLUGIN_DATA}"');
+    expect(fs.readdirSync(foreign)).toEqual([]);
+  });
+
+  it("rejects an unsubstituted placeholder before creating anything", () => {
+    const foreign = foreignDataDir();
+    const result = runSetupDeps(["--data-dir", "<plugin-data>"], { CLAUDE_PLUGIN_DATA: foreign });
+    expect(result.status).toBe(2);
+    expect(result.stderr).toContain("unsubstituted placeholder");
+    expect(fs.readdirSync(foreign)).toEqual([]);
+  });
+
+  it("rejects a flag it does not take", () => {
+    const result = runSetupDeps(["--work-root", "/proj"], { CLAUDE_PLUGIN_DATA: foreignDataDir() });
+    expect(result.status).toBe(2);
+    expect(result.stderr).toContain("takes only `--data-dir <dir>`");
+  });
+});
diff --git a/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.js b/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.js
index 3ad8ba42ff..177be1c10c 100755
--- a/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.js
+++ b/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.js
@@ -11,6 +11,7 @@ import path from "node:path";
 import { isMainModule } from "@melodic/video-digestion/shared/main-module";
 import { writeStderr, writeStdout } from "@melodic/video-digestion/shared/terminal";
 
+import { resolvePluginData } from "../lib/run-args.js";
 import { LANES, lanePath } from "../lib/slice-lanes.js";
 import { resolveTempSession } from "../lib/temp-session-paths.js";
 import { watchStatePath } from "./watch-state.js";
@@ -99,6 +100,10 @@ export function detectRecoverableBootstrap(sliceDir) {
 }
 
 /**
+ * The command the agent runs through the Bash tool, whose environment has neither
+ * plugin variable: the launcher's absolute path, and the data directory `run.mjs`
+ * resolved for this process when it names this plugin.
+ *
  * @param {string} sliceDir
  * @returns {string}
  */
@@ -108,7 +113,10 @@ export function formatRecoverCommand(sliceDir) {
     return "";
   }
   const { workDir, framesDir, contactSheetsDir } = detection.tempSession;
-  return `node "\${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" watch/recover-watch-bootstrap.js "${sliceDir}" "${workDir}" "${framesDir}" "${contactSheetsDir}"`;
+  const launcher = path.join(import.meta.dirname, "..", "run.mjs").split(path.sep).join("/");
+  const dataDir = resolvePluginData(undefined, process.env);
+  const dataFlag = dataDir ? ` --data-dir "${dataDir}"` : "";
+  return `node "${launcher}"${dataFlag} watch/recover-watch-bootstrap.js "${sliceDir}" "${workDir}" "${framesDir}" "${contactSheetsDir}"`;
 }
 
 /**
diff --git a/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.test.js b/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.test.js
index 0671e6c9f7..fd554ae4d9 100644
--- a/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.test.js
+++ b/plugins/knowledge/skills/video-digest/extraction/watch/detect-recoverable-bootstrap.test.js
@@ -1,8 +1,9 @@
+import { spawnSync } from "node:child_process";
 import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 
-import { afterAll, describe, expect, it } from "vitest";
+import { afterAll, describe, expect, it, vi } from "vitest";
 
 import {
   detectRecoverableBootstrap,
@@ -84,6 +85,33 @@ describe("detectRecoverableBootstrap", () => {
     expect(formatRecoverCommand(tmp)).not.toContain("youtube-digest");
   });
 
+  it("names the launcher by absolute path and passes the plugin's own data dir", () => {
+    const { framesDir, sheetsDir } = makeFrameAndSheetDirs();
+    const tmp = makeSliceDir({
+      phases: {},
+      tempSession: { workDir: makeWorkDir("captions.vtt"), framesDir, contactSheetsDir: sheetsDir },
+    });
+    const knowledgeData = "/var/fixture/claude/plugins/data/knowledge-melodic-software";
+
+    vi.stubEnv("CLAUDE_PLUGIN_DATA", knowledgeData);
+    try {
+      const match = /^node "([^"]+)" --data-dir "([^"]+)" watch\/recover-watch-bootstrap\.js /.exec(
+        formatRecoverCommand(tmp),
+      );
+      expect(match).not.toBeNull();
+      const [, launcher, dataDir] = /** @type {RegExpExecArray} */ (match);
+      expect(path.isAbsolute(launcher)).toBe(true);
+      expect(launcher.endsWith("/skills/video-digest/extraction/run.mjs")).toBe(true);
+      expect(fs.existsSync(launcher)).toBe(true);
+      expect(dataDir).toBe(knowledgeData);
+      vi.stubEnv("CLAUDE_PLUGIN_DATA", "/var/fixture/claude/plugins/data/codex-openai-codex");
+      expect(formatRecoverCommand(tmp)).not.toContain("--data-dir");
+      expect(formatRecoverCommand(tmp)).not.toContain("codex-openai-codex");
+    } finally {
+      vi.unstubAllEnvs();
+    }
+  });
+
   it("accepts an auto-caption-only workDir (*-orig.vtt)", () => {
     const { framesDir, sheetsDir } = makeFrameAndSheetDirs();
     const tmp = makeSliceDir({
@@ -115,6 +143,40 @@ describe("detectRecoverableBootstrap", () => {
   });
 });
 
+describe("run.mjs hands its child only the resolved data dir", () => {
+  const launcher = path.join(import.meta.dirname, "..", "run.mjs");
+  const codex = "/var/fixture/claude/plugins/data/codex-openai-codex";
+
+  /** The recover command the CLI prints when run through the launcher with these args. */
+  function recoverCommandVia(launcherArgs) {
+    const { framesDir, sheetsDir } = makeFrameAndSheetDirs();
+    const slice = makeSliceDir({
+      phases: {},
+      tempSession: { workDir: makeWorkDir("captions.vtt"), framesDir, contactSheetsDir: sheetsDir },
+    });
+    const result = spawnSync(
+      process.execPath,
+      [launcher, ...launcherArgs, "watch/detect-recoverable-bootstrap.js", slice, "--json"],
+      { encoding: "utf8", timeout: 20000, env: { ...process.env, CLAUDE_PLUGIN_DATA: codex } },
+    );
+    expect(result.status, result.stderr).toBe(0);
+    return JSON.parse(result.stdout).recoverCommand;
+  }
+
+  it("replaces an inherited value naming another plugin with the --data-dir value", () => {
+    const knowledge = "/var/fixture/claude/plugins/data/knowledge-melodic-software";
+    const command = recoverCommandVia(["--data-dir", knowledge]);
+    expect(command).toContain(`--data-dir "${knowledge}"`);
+    expect(command).not.toContain("codex-openai-codex");
+  });
+
+  it("never passes on an inherited value naming another plugin when no flag is given", () => {
+    const command = recoverCommandVia([]);
+    expect(command).not.toContain("--data-dir");
+    expect(command).not.toContain("codex-openai-codex");
+  });
+});
+
 describe("resolveWorkArtifacts", () => {
   it("resolves an auto-caption-only workDir via the *-orig.vtt fallback", () => {
     const artifacts = resolveWorkArtifacts(makeWorkDir("captions.en-orig.vtt"));
diff --git a/plugins/knowledge/skills/video-digest/reference/sources/youtube.md b/plugins/knowledge/skills/video-digest/reference/sources/youtube.md
index 925daacc27..6a72ccff10 100644
--- a/plugins/knowledge/skills/video-digest/reference/sources/youtube.md
+++ b/plugins/knowledge/skills/video-digest/reference/sources/youtube.md
@@ -64,7 +64,7 @@ Example combining a non-default library dir with a forced cookie source (unset o
 contribute no flag):
 
 ```bash
-node "<skill-dir>/extraction/run.mjs" \
+node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" \
   --work-root "${CLAUDE_PROJECT_DIR}/${user_config.library_dir}" \
   --cookies-from-browser "${user_config.yt_dlp_cookies_from_browser}" \
   <script.js> [args…]
diff --git a/plugins/knowledge/skills/video-digest/templates/watch-checklist.md b/plugins/knowledge/skills/video-digest/templates/watch-checklist.md
index 81bd98c5b2..31d0a99cc3 100644
--- a/plugins/knowledge/skills/video-digest/templates/watch-checklist.md
+++ b/plugins/knowledge/skills/video-digest/templates/watch-checklist.md
@@ -12,7 +12,7 @@ Tick only after verification evidence. Criteria SSOT: `quality-gates.md` (the `/
 
 ## Phase 0: Prerequisites
 
-- [ ] **0.1** video-extraction deps installed. Verify: `node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/setup-deps.mjs"` exit 0
+- [ ] **0.1** video-extraction deps installed. Verify: `node "<skill-dir>/extraction/setup-deps.mjs" --data-dir "<plugin-data>"` exit 0
 - [ ] **0.2** yt-dlp available. Verify: SKILL pre-computed context ≠ MISSING
 - [ ] **0.3** ffmpeg available (watch only). Verify: SKILL pre-computed context ≠ MISSING
 - [ ] **0.4** ImageMagick 7 available (watch only). Verify: SKILL pre-computed context ≠ MISSING
@@ -89,7 +89,7 @@ Tick only after verification evidence. Criteria SSOT: `quality-gates.md` (the `/
 - [ ] **7.2** Per done cluster: finding file or inline in `RESEARCH.md`. Verify: research outcome gate per cluster
 - [ ] **7.3** `RESEARCH.md` slice summary. Verify: ≥200 chars; conflicts + gaps sections
 - [ ] **7.4** Top harvested URLs fetched; repos analyzed to temp if GitHub links. Verify: fetch log / `analyze-harvested-repos.js` when applicable
-- [ ] **7.5** Research verify. Verify: `node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" evals/check-research-complete.js "<slice-dir>"` exit 0
+- [ ] **7.5** Research verify. Verify: `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" evals/check-research-complete.js "<slice-dir>"` exit 0
 - [ ] **7.6** `mark-phase <slice-dir> research` only after 7.5. Verify: `watch.json`
 
 ## Phase 8: Synthesis
@@ -105,7 +105,7 @@ Tick only after verification evidence. Criteria SSOT: `quality-gates.md` (the `/
 
 ## Phase 9: Outcome verification (mandatory before complete)
 
-- [ ] **9.1** Host verify. Verify: `node "${CLAUDE_PLUGIN_ROOT}/skills/video-digest/extraction/run.mjs" evals/check-watch-outcomes.js "<slice-dir>" --write-report` exit 0
+- [ ] **9.1** Host verify. Verify: `node "<skill-dir>/extraction/run.mjs" --data-dir "<plugin-data>" evals/check-watch-outcomes.js "<slice-dir>" --write-report` exit 0
 - [ ] **9.2** `verification/<ISO-basic>Z-watch-outcomes.md` shows PASS. Verify: all `fail` severity checks green
 - [ ] **9.3** `watch-state.js close <slice-dir>` exit 0 after 9.1, 9.2 and 9.4; it is the only writer of `status: complete`. Verify: `watch.json` `status: complete`
 - [ ] **9.4** Vision fidelity spot-check (required for a vision-complete claim). Verify: ≥10 synthesis PNG images name↔content + ≥3 contact sheets verdict↔JPG; notes in Resume notes below. Verify script exit 0 alone is structural only.