diff --git a/.changeset/calm-tigers-click.md b/.changeset/calm-tigers-click.md
new file mode 100644
index 000000000..8fa6c8e95
--- /dev/null
+++ b/.changeset/calm-tigers-click.md
@@ -0,0 +1,5 @@
+---
+type: Fixed
+pr: 515
+---
+Remove dead SDK-shim verification subsystem (installSdkIfNeeded and 17 transitively-called functions) from bin/install.js. Post-ADR-0174 sdk/ no longer ships; the subsystem had no live callers and could produce misleading 'tarball is missing sdk/dist/' errors. detectStaleStandaloneSdk and formatStaleStandaloneSdkWarning are kept (handle real stale-global-SDK condition).
diff --git a/bin/install.js b/bin/install.js
index e33bb4c81..2eecb8e6f 100755
--- a/bin/install.js
+++ b/bin/install.js
@@ -10692,341 +10692,6 @@ function maybeSuggestPathExport(globalBin, homeDir) {
   console.log('');
 }
 
-/**
- * Verify the prebuilt SDK dist is present and the gsd-sdk shim is wired up.
- *
- * As of fix/2441-sdk-decouple, sdk/dist/ is shipped prebuilt inside the
- * @opengsd/get-shit-done-redux npm tarball. The parent package declares a bin entry
- * "gsd-sdk": "bin/gsd-sdk.js" so npm chmods the shim correctly when
- * installing from a packed tarball — eliminating the mode-644 failure
- * (issue #2453) and the build-from-source failure modes (#2439, #2441).
- *
- * This function verifies the invariant: sdk/dist/cli.js exists and is
- * executable. If the execute bit is missing (possible in dev/clone setups
- * where sdk/dist was committed without +x), we fix it in-place.
- *
- * --no-sdk skips the check entirely (back-compat).
- * --sdk forces the check even if it would otherwise be skipped.
- */
-/**
- * Classify the install context for the SDK directory.
- *
- * Distinguishes three shapes the installer must handle differently when
- * `sdk/dist/` is missing:
- *
- *   - `tarball` + `npxCache: true`
- *       User ran `npx @opengsd/get-shit-done-redux@latest`. sdk/ lives under
- *       `<npm-cache>/_npx/<hash>/node_modules/@opengsd/get-shit-done-redux/sdk` which
- *       is treated as read-only by npm/npx on Windows (#2649). We MUST
- *       NOT attempt a nested `npm install` there — it will fail with
- *       EACCES/EPERM and produce the misleading "Failed to npm install
- *       in sdk/" error the user reported. Point at the global upgrade.
- *
- *   - `tarball` + `npxCache: false`
- *       User ran a global install (`npm i -g @opengsd/get-shit-done-redux`). sdk/dist
- *       ships in the published tarball; if it's missing, the published
- *       artifact itself is broken (see #2647). Same user-facing fix:
- *       upgrade to latest.
- *
- *   - `dev-clone`
- *       Developer running from a git clone. Keep the existing "cd sdk &&
- *       npm install && npm run build" hint — the user is expected to run
- *       that themselves. The installer itself never shells out to npm.
- *
- * Detection heuristics are path-based and side-effect-free: we look for
- * `_npx` and `node_modules` segments that indicate a packaged install,
- * and for a `.git` directory nearby that indicates a clone. A best-effort
- * write probe detects read-only filesystems (tmpfile create + unlink);
- * probe failures are treated as read-only.
- */
-function classifySdkInstall(sdkDir) {
-  const path = require('path');
-  const fs = require('fs');
-  const segments = sdkDir.split(/[\\/]+/);
-  const npxCache = segments.includes('_npx');
-  const inNodeModules = segments.includes('node_modules');
-  const parent = path.dirname(sdkDir);
-  const hasGitNearby = fs.existsSync(path.join(parent, '.git'));
-
-  let mode;
-  if (hasGitNearby && !npxCache && !inNodeModules) {
-    mode = 'dev-clone';
-  } else if (npxCache || inNodeModules) {
-    mode = 'tarball';
-  } else {
-    mode = 'dev-clone';
-  }
-
-  let readOnly = npxCache; // assume true for npx cache
-  if (!readOnly) {
-    try {
-      const probe = path.join(sdkDir, `.gsd-write-probe-${process.pid}`);
-      fs.writeFileSync(probe, '');
-      fs.unlinkSync(probe);
-    } catch {
-      readOnly = true;
-    }
-  }
-
-  return { mode, npxCache, readOnly };
-}
-
-/**
- * #2974: pure builder for the SDK fail-fast report. Returns a structured IR
- * with everything the renderer needs PLUS everything tests need to assert
- * on. Tests can call `buildSdkFailFastReport(sdkDir, sdkCliPath)` directly
- * and assert on `report.reason`, `report.context`, `report.fix_command`
- * etc. without intercepting console.error or matching against rendered
- * text.
- *
- * Shape (frozen contract — extending requires a new test):
- *   {
- *     ok: false,
- *     reason: 'sdk_fail_fast',                 // ERROR_REASON.SDK_FAIL_FAST
- *     context: 'npx-cache' | 'tarball' | 'dev-clone',
- *     missing_path: '<path>/sdk/dist/cli.js',
- *     missing_artifact: 'sdk/dist',
- *     fix_command: 'npm install -g @opengsd/get-shit-done-redux@latest' | 'cd sdk && npm install && npm run build',
- *     attempted_nested_install: false,         // contract: never true
- *   }
- */
-function buildSdkFailFastReport(sdkDir, sdkCliPath) {
-  const ctx = classifySdkInstall(sdkDir);
-  let context, fix_command;
-  if (ctx.mode === 'tarball') {
-    context = ctx.npxCache ? 'npx-cache' : 'tarball';
-    fix_command = 'npm install -g @opengsd/get-shit-done-redux@latest';
-  } else {
-    context = 'dev-clone';
-    fix_command = 'cd sdk && npm install && npm run build';
-  }
-  return {
-    ok: false,
-    reason: 'sdk_fail_fast',
-    context,
-    missing_path: sdkCliPath,
-    missing_artifact: 'sdk/dist',
-    fix_command,
-    attempted_nested_install: false,
-  };
-}
-
-/**
- * Renderer for the structured fail-fast report. Text formatting only —
- * tests never call this. Splits the IR fields back into the same human-
- * readable lines the previous shape produced.
- */
-function renderSdkFailFastReport(ir) {
-  const bar = '━'.repeat(72);
-  const redBold = `${red}${bold}`;
-  console.error('');
-  console.error(`${redBold}${bar}${reset}`);
-  console.error(`${redBold}  ✗ GSD SDK dist not found — /gsd-* commands will not work${reset}`);
-  console.error(`${redBold}${bar}${reset}`);
-  console.error(`  ${red}Reason:${reset} ${ir.missing_artifact}/cli.js not found at ${ir.missing_path}`);
-  console.error('');
-  if (ir.context === 'npx-cache') {
-    console.error(`  Detected read-only npx cache install (${dim}${path.dirname(ir.missing_path).replace(/\/dist$/, '')}${reset}).`);
-    console.error(`  The installer will ${bold}not${reset} attempt \`npm install\` inside the npx cache.`);
-    console.error('');
-    console.error(`  Fix: install a version that ships sdk/dist/ globally:`);
-    console.error(`    ${cyan}${ir.fix_command}${reset}`);
-    console.error(`  Or, if you prefer a one-shot run, clear the npx cache first:`);
-    console.error(`    ${cyan}npx --yes @opengsd/get-shit-done-redux@latest${reset}`);
-    console.error(`  Or build from source (git clone):`);
-    console.error(`    ${cyan}git clone https://github.com/open-gsd/get-shit-done-redux && cd get-shit-done/sdk && npm install && npm run build${reset}`);
-  } else if (ir.context === 'tarball') {
-    console.error(`  The published tarball appears to be missing sdk/dist/ (see #2647).`);
-    console.error('');
-    console.error(`  Fix: install a version that ships sdk/dist/ globally:`);
-    console.error(`    ${cyan}${ir.fix_command}${reset}`);
-    console.error(`  Or build from source (git clone):`);
-    console.error(`    ${cyan}git clone https://github.com/open-gsd/get-shit-done-redux && cd get-shit-done/sdk && npm install && npm run build${reset}`);
-  } else {
-    console.error(`  Running from a git clone — build the SDK first:`);
-    console.error(`    ${cyan}${ir.fix_command}${reset}`);
-  }
-  console.error(`${redBold}${bar}${reset}`);
-  console.error('');
-}
-
-function installSdkIfNeeded(opts) {
-  opts = opts || {};
-  if (hasNoSdk && !opts.sdkDir) {
-    console.log(`\n  ${dim}Skipping GSD SDK check (--no-sdk)${reset}`);
-    return;
-  }
-
-  const path = require('path');
-  const fs = require('fs');
-
-  const sdkDir = opts.sdkDir || path.resolve(__dirname, '..', 'sdk');
-  const sdkCliPath = path.join(sdkDir, 'dist', 'cli.js');
-
-  // #2678 / #2829: local installs do not write to global node_modules, so we
-  // cannot fall through to the global-install error path. But the parent
-  // package (which carries bin/gsd-sdk.js and sdk/dist/cli.js) IS available
-  // wherever the installer is running from — npx cache, npm-global, or git
-  // clone. The shim resolves sdk/dist/cli.js relative to its own __dirname,
-  // so a self-link into a user-writable PATH dir makes `gsd-sdk` callable
-  // from local-mode installs too. Only when the dist is genuinely missing
-  // do we bail out with a non-fatal warning.
-  //
-  // #3033: --sdk (opts.forceSdk) overrides the local-install early-return —
-  // the user explicitly requested SDK deployment, so treat the missing-dist
-  // case like a global install (fail fast with an actionable diagnostic)
-  // instead of silently skipping.
-  if (opts.isLocal && !opts.forceSdk && !fs.existsSync(sdkCliPath)) {
-    console.warn(`\n  ${yellow}⚠${reset}  Skipping SDK check for local install — sdk/dist/cli.js not found at ${sdkCliPath}.`);
-    return;
-  }
-
-  if (!fs.existsSync(sdkCliPath)) {
-    const ir = buildSdkFailFastReport(sdkDir, sdkCliPath);
-    renderSdkFailFastReport(ir);
-    if (opts.throwOnFailure) {
-      const error = new Error(`GSD SDK prebuilt artifact missing: ${sdkCliPath}`);
-      error.code = 'GSD_SDK_MISSING_DIST';
-      error.exitCode = 1;
-      throw error;
-    }
-    process.exit(1);
-  }
-
-  // Ensure execute bit is set. tsc emits files at 0o644; git clone preserves
-  // whatever mode was committed. Fix in-place so node-invoked paths work too.
-  try {
-    const stat = fs.statSync(sdkCliPath);
-    const isExecutable = !!(stat.mode & 0o111);
-    if (!isExecutable) {
-      fs.chmodSync(sdkCliPath, stat.mode | 0o111);
-    }
-  } catch {
-    // Non-fatal: if chmod fails (e.g. read-only fs) the shim still works via
-    // `node sdkCliPath` invocation in bin/gsd-sdk.js.
-  }
-
-  // #2775: do not assert "GSD SDK ready" until `gsd-sdk` actually resolves on
-  // PATH. `npx @opengsd/get-shit-done-redux` only links the package's primary bin; the
-  // secondary `gsd-sdk` shim is left dangling under the npx cache and is NOT
-  // callable as a bare command. The previous file-presence-only check was a
-  // strictly weaker invariant than the one workflows depend on
-  // (`command -v gsd-sdk` resolving), and led to a false ✓ in npx-cache
-  // installs (issue #2775).
-  //
-  // #3231: strip transient npx-injected PATH segments before checking. The
-  // installer subprocess PATH includes `~/.npm/_npx/<hash>/node_modules/.bin`
-  // which is ephemeral — it is NOT reachable from the user's interactive
-  // shell. A gsd-sdk found there must NOT count as "on PATH".
-  const shimSrc = path.resolve(__dirname, 'gsd-sdk.js');
-  const persistentPath = filterNpxFromPath(process.env.PATH || '');
-  let resolvedSdkPath = findGsdSdkOnPath(persistentPath);
-  let onPath = !!resolvedSdkPath;
-
-  // Track WHERE we wrote the shim so the diagnostic can be specific even
-  // when isGsdSdkOnPath() returns false because the write target isn't on
-  // PATH (#3011: Windows users hit this when npm's global bin dir is
-  // populated but not on every shell's PATH — Git Bash vs PowerShell vs
-  // cmd.exe each read PATH from different sources).
-  let shimDir = null;
-  if (!onPath) {
-    // Try to materialize the shim into a user-writable PATH location so the
-    // installer can deliver on the success message without requiring the user
-    // to run `npm install -g` separately. Picks the first PATH entry that
-    // looks like a user-owned bin dir; falls back to ~/.local/bin even if
-    // it's not on PATH (then a follow-up suggestion is printed).
-    const linked = trySelfLinkGsdSdk(shimSrc);
-    if (linked) {
-      shimDir = path.dirname(linked);
-      resolvedSdkPath = findGsdSdkOnPath(persistentPath);
-      onPath = !!resolvedSdkPath;
-      if (onPath) {
-        console.log(`  ${dim}↪ linked gsd-sdk → ${linked}${reset}`);
-      }
-    }
-  }
-
-  // #3020: cross-shell PATH verification. Even when the install-time
-  // process.env.PATH walk found the shim, the user's later interactive
-  // shells may have a different PATH — Windows cross-shell .cmd/no-ext
-  // mismatch, POSIX ~/.local/bin missing from login shell, or node-
-  // version-manager PATH shims. Probe the user's login shell PATH and
-  // require the shim to be reachable there too before claiming ✓.
-  //
-  // #3211 (Windows): getUserShellWindowsPersistentPath() reads the user-level
-  // 'Path' registry key via PowerShell — the correct cross-shell source on
-  // Windows (Git Bash, PowerShell, and cmd.exe all inherit it). Returns null
-  // when PowerShell is unavailable or the probe times out.
-  //
-  // #3231: when getUserShellPath() / getUserShellWindowsPersistentPath()
-  // returns null (probe failed or unavailable), we cannot confirm persistent
-  // reachability. Since we already filtered npx dirs from persistentPath above,
-  // onPath=true means a non-transient dir has the shim — that is the best
-  // available invariant and is sufficient to claim ✓.
-  const userShellPath = process.platform === 'win32'
-    ? getUserShellWindowsPersistentPath()
-    : getUserShellPath();
-  if (onPath && userShellPath !== null) {
-    // filterNpxFromPath is applied inside getUserShellWindowsPersistentPath
-    // (Windows) and here for the POSIX case.
-    const persistentUserShellPath = process.platform === 'win32'
-      ? userShellPath  // already filtered by getUserShellWindowsPersistentPath
-      : filterNpxFromPath(userShellPath);
-    const userSdkPath = findGsdSdkOnPath(persistentUserShellPath);
-    if (!userSdkPath) {
-      onPath = false;
-      resolvedSdkPath = null;
-    } else {
-      resolvedSdkPath = userSdkPath;
-    }
-  }
-  // If userShellPath is null (probe failed or unavailable), onPath reflects
-  // the persistent-PATH check — that is the best available invariant.
-
-  if (onPath) {
-    const versionReport = buildGsdSdkVersionMismatchReport(resolvedSdkPath, pkg.version, { isLocal: !!opts.isLocal });
-    if (versionReport) {
-      renderGsdSdkVersionMismatchReport(versionReport);
-    } else {
-      console.log(`  ${green}✓${reset} GSD SDK ready (sdk/dist/cli.js)`);
-    }
-  } else {
-    // #3011: actionable diagnostic. The previous shape printed a generic
-    // "not on your PATH" message that didn't tell the user where to look.
-    // formatSdkPathDiagnostic produces a typed IR that we then render to
-    // stdout; tests assert on the IR (no source-grep, no console capture).
-    const ir = formatSdkPathDiagnostic({
-      shimDir,
-      platform: process.platform,
-      runDir: __dirname,
-    });
-    console.log('');
-    console.log(`  ${yellow}⚠${reset} GSD SDK files are present but ${bold}gsd-sdk${reset} is not on your PATH.`);
-    console.log(`    Workflows that call ${cyan}gsd-sdk query …${reset} will fail with "command not found".`);
-    if (ir.shimLocationLine) console.log(`    ${ir.shimLocationLine}`);
-    for (const line of ir.actionLines) console.log(`    ${line}`);
-    if (ir.npxNoteLines.length > 0) {
-      for (const line of ir.npxNoteLines) console.log(`    ${line}`);
-    }
-    console.log('');
-  }
-
-  // #2620: warn if npm's global bin is not on PATH, suppressing the
-  // absolute-path suggestion when the user's rc already covers it via
-  // a HOME-relative entry (e.g. `export PATH="$HOME/.npm-global/bin:$PATH"`).
-  try {
-    const cp = require('child_process');
-    const npmPrefix = cp.execSync('npm prefix -g', { encoding: 'utf8', stdio: ['ignore', 'pipe', 'ignore'] }).trim();
-    if (npmPrefix) {
-      // On Windows npm prefix IS the bin dir; on POSIX it's `${prefix}/bin`.
-      const globalBin = process.platform === 'win32' ? npmPrefix : path.join(npmPrefix, 'bin');
-      maybeSuggestPathExport(globalBin, os.homedir());
-    }
-  } catch {
-    // npm not available / exec failed — silently skip the PATH advice.
-  }
-}
-
 /**
  * #3406 helper: detect a stale globally-installed `@opengsd/gsd-sdk` package
  * shadowing the `gsd-sdk` shim that `@opengsd/get-shit-done-redux` installs.
@@ -11101,483 +10766,20 @@ function formatStaleStandaloneSdkWarning(info) {
   ].join('\n');
 }
 
-/**
- * #3231 helper: detect whether a `gsd-sdk` binary is the legacy deprecated
- * shim pointing at `gsd-tools.cjs`.
- *
- * Reads the first 512 bytes of the file and looks for the `@deprecated`
- * marker alongside a `gsd-tools.cjs` reference — the fingerprint that
- * distinguishes the old binary from the modern SDK. Treats any I/O error
- * (missing file, EACCES) as "not legacy" so callers do not need to guard.
- *
- * This is intentionally a plain-text sniff of the file header, not a
- * semantic parse — the marker is a stable, human-authored string that we
- * own. Returns false conservatively (prefer false positives to false
- * negatives: a non-legacy binary reported as legacy triggers a harmless
- * replacement; a legacy binary reported as non-legacy would keep the broken
- * shim in place).
- */
-function isLegacyGsdSdkShim(filePath) {
-  const fs = require('fs');
-  try {
-    const fd = fs.openSync(filePath, 'r');
-    let header;
-    try {
-      const buf = Buffer.alloc(512);
-      const bytesRead = fs.readSync(fd, buf, 0, 512, 0);
-      header = buf.slice(0, bytesRead).toString('utf8');
-    } finally {
-      try { fs.closeSync(fd); } catch {}
-    }
-    // The legacy binary contains "@deprecated" AND "gsd-tools.cjs" within
-    // its first 512 bytes.
-    return header.includes('@deprecated') && header.includes('gsd-tools.cjs');
-  } catch {
-    return false;
-  }
-}
-
-/**
- * #3231 helper: strip transient npx-injected PATH segments.
- *
- * npm/npx injects `~/.npm/_npx/<hash>/node_modules/.bin` (and equivalents)
- * into the installer subprocess PATH. Those directories are ephemeral — they
- * exist only for the duration of the `npx` run — and MUST NOT be treated as
- * evidence that `gsd-sdk` is durably reachable.
- *
- * Strips any segment whose absolute form contains `/_npx/` or `\\_npx\\`
- * as a proper path-component boundary.  A user-named directory that merely
- * contains the substring "npx" (e.g. `/home/user/my-npx-scripts/bin`) is
- * preserved: we require the boundary characters (`/` or `\`) on both sides.
- *
- * Returns the filtered PATH string (may be empty if all segments were npx).
- */
-function filterNpxFromPath(pathString) {
-  const path = require('path');
-  const input = typeof pathString === 'string' ? pathString : (process.env.PATH || '');
-  return input
-    .split(path.delimiter)
-    .filter((seg) => {
-      if (!seg) return false;
-      // Normalize to forward-slash form for the pattern check so both
-      // POSIX and Windows paths match a single expression. The sep-anchored
-      // pattern avoids matching "my-npx-scripts" etc.
-      const norm = seg.replace(/\\/g, '/');
-      // Must have /_npx/ as a real path component, not just a substring.
-      return !norm.includes('/_npx/');
-    })
-    .join(path.delimiter);
-}
-
-/**
- * #2775 helper: find a callable `gsd-sdk` on a PATH.
- *
- * Pure PATH walk (no spawn) — we look for a regular file or symlink named
- * `gsd-sdk` (or `gsd-sdk.cmd`/`.exe` on Windows) in any directory on PATH and
- * verify it carries the execute bit on POSIX. Avoids paying spawn cost and
- * avoids the chicken-and-egg of needing to run the not-yet-installed binary.
- *
- * #3020: accepts an optional explicit PATH string. The install subprocess's
- * process.env.PATH is not the same set the user's later interactive shells
- * see (Windows cross-shell, POSIX ~/.local/bin, node-version-manager
- * shims). Callers can pass the user-shell PATH from getUserShellPath() to
- * verify the shim is reachable from the runtime shell, not just the
- * install context. Zero-arg form preserves existing behavior.
- *
- * #3231: a candidate that passes the file/exec check is further tested via
- * isLegacyGsdSdkShim — a symlink pointing at the deprecated gsd-tools.cjs
- * binary must NOT be treated as "on PATH" even if it is executable.
- */
-function findGsdSdkOnPath(pathString) {
-  const path = require('path');
-  const fs = require('fs');
-  // Type-guard the explicit input (#3028 CR): callers may pass null
-  // (getUserShellPath() can return null), and `null.split()` throws.
-  // Only honor pathString when it's a string; fall back otherwise.
-  const pathEnv = typeof pathString === 'string' ? pathString : (process.env.PATH || '');
-  const exts = process.platform === 'win32' ? ['.cmd', '.exe', '.bat', ''] : [''];
-  for (const seg of pathEnv.split(path.delimiter)) {
-    if (!seg) continue;
-    for (const ext of exts) {
-      const candidate = path.join(seg, `gsd-sdk${ext}`);
-      try {
-        const st = fs.statSync(candidate);
-        if (st.isFile()) {
-          if (process.platform === 'win32') {
-            if (!isLegacyGsdSdkShim(candidate)) return candidate;
-          } else if ((st.mode & 0o111) !== 0) {
-            // #3231: resolve symlink before sniffing, so we detect legacy
-            // through any level of indirection.
-            let target = candidate;
-            try { target = fs.realpathSync(candidate); } catch {}
-            if (!isLegacyGsdSdkShim(target)) return candidate;
-          }
-        }
-      } catch {
-        // missing / EACCES on dir — keep scanning.
-      }
-    }
-  }
-  return null;
-}
-
-function isGsdSdkOnPath(pathString) {
-  return !!findGsdSdkOnPath(pathString);
-}
-
-function parseGsdSdkVersion(text) {
-  const match = String(text || '').match(/\bv?(\d+\.\d+\.\d+(?:-[0-9A-Za-z.-]+)?)\b/);
-  return match ? match[1] : null;
-}
-
-function readGsdSdkVersion(sdkPath) {
-  if (!sdkPath) return null;
-  const cp = require('child_process');
-  try {
-    const isWindowsCommandShim = process.platform === 'win32' && /\.(cmd|bat)$/i.test(String(sdkPath));
-    const result = cp.spawnSync(isWindowsCommandShim ? 'cmd.exe' : sdkPath, isWindowsCommandShim ? ['/c', sdkPath, '--version'] : ['--version'], {
-      encoding: 'utf8',
-      stdio: ['ignore', 'pipe', 'pipe'],
-      timeout: 2000,
-      env: process.env,
-    });
-    if (result.error || result.status !== 0) return null;
-    return parseGsdSdkVersion(`${result.stdout || ''}\n${result.stderr || ''}`);
-  } catch {
-    return null;
-  }
-}
-
-function buildGsdSdkVersionMismatchReport(sdkPath, expectedVersion, opts) {
-  const actualVersion = readGsdSdkVersion(sdkPath);
-  if (!actualVersion || !expectedVersion) return null;
-  if (actualVersion === expectedVersion) return null;
-  // #3668: local installs should NOT be told to run `npm install -g` —
-  // that contradicts the intent of --local (self-contained, no global dep).
-  // For local installs the correct remediation is to re-run the local
-  // installer (e.g. `npx get-shit-done-cc@latest --claude --local`).
-  const isLocal = opts && opts.isLocal;
-  const fix_command = isLocal
-    ? 'npx @opengsd/get-shit-done-redux@latest --claude --local'
-    : 'npm install -g @opengsd/get-shit-done-redux@latest';
-  return {
-    ok: false,
-    reason: 'gsd_sdk_version_mismatch',
-    sdk_path: sdkPath,
-    actual_version: actualVersion,
-    expected_version: expectedVersion,
-    fix_command,
-    is_local: !!isLocal,
-  };
-}
-
-function renderGsdSdkVersionMismatchReport(ir) {
-  console.log('');
-  console.log(`  ${yellow}⚠${reset} ${bold}gsd-sdk version mismatch${reset} — PATH resolves a stale SDK.`);
-  console.log(`    Resolved gsd-sdk: ${ir.sdk_path}`);
-  console.log(`    Resolved version: ${ir.actual_version}`);
-  console.log(`    Installer version: ${ir.expected_version}`);
-  console.log(`    Workflows that call ${cyan}gsd-sdk query …${reset} will use the stale executable first.`);
-  console.log(`    Fix: ${cyan}${ir.fix_command}${reset}`);
-  console.log(`    Or remove the stale global install / adjust PATH so the current shim is first.`);
-  console.log('');
-}
-
-/**
- * #3020: probe the user's login shell to learn the PATH that will be
- * visible at workflow runtime.
- *
- * The install subprocess inherits process.env.PATH from npm/npx, which
- * may include directories the user's interactive shells do not (e.g.
- * ~/.local/bin auto-injected by npm-prefix tooling, or nvm-shimmed
- * paths). Asserting `gsd-sdk` is on the install-subprocess PATH is a
- * weaker invariant than the runtime contract — workflows shell out via
- * `bash -c "gsd-sdk …"`, and that bash inherits PATH from the user's
- * login shell.
- *
- * Uses `$SHELL -lc 'printf %s "$PATH"'` on POSIX. Returns null on Windows
- * (the Windows counterpart is getUserShellWindowsPersistentPath, which reads
- * the user-level 'Path' registry key via PowerShell). Returns null
- * when $SHELL is unset, when the spawn fails, or when the result is
- * empty — callers must fall back to process.env.PATH in those cases.
- *
- * Synchronous so it can be called from the existing post-install check
- * without restructuring the whole flow as async.
- */
-function getUserShellPath() {
-  if (process.platform === 'win32') return null;
-  const shellEnv = typeof process.env.SHELL === 'string' ? process.env.SHELL : '';
-  if (!shellEnv) return null;
-  const cp = require('child_process');
-  try {
-    const out = cp.execFileSync(shellEnv, ['-lc', 'printf %s "$PATH"'], {
-      encoding: 'utf8',
-      stdio: ['ignore', 'pipe', 'pipe'],
-      // 2-second cap so a misconfigured rc file (e.g. interactive prompt)
-      // can't hang the install. The probe is best-effort — null on timeout
-      // is the safe fallback.
-      timeout: 2000,
-    });
-    // #3028 CR: login startup scripts can print banners / motd / stale
-    // log lines BEFORE the printf, polluting stdout. Take the LAST
-    // non-empty line as the PATH candidate so noise doesn't flip the
-    // cross-shell check to false. PATH itself is single-line.
-    const lines = String(out || '').split(/\r?\n/).map((s) => s.trim()).filter(Boolean);
-    const candidate = lines.length > 0 ? lines[lines.length - 1] : '';
-    return candidate.length > 0 ? candidate : null;
-  } catch {
-    return null;
-  }
-}
-
-/**
- * #3211: Windows counterpart to getUserShellPath(). Probes the effective
- * persistent Path from the Windows registry via PowerShell by merging
- * Machine-level + User-level entries:
- *
- *   $m=[Environment]::GetEnvironmentVariable('Path','Machine')
- *   $u=[Environment]::GetEnvironmentVariable('Path','User')
- *   ($m + ';' + $u).Trim(';')
- *
- * This is the correct primitive for Windows cross-shell PATH verification —
- * Git Bash, PowerShell, and cmd.exe all inherit the effective (Machine;User)
- * registry Path, while the install-subprocess process.env.PATH is polluted
- * with transient npx entries and may not include directories added by the
- * user post-install. Reading only User-level Path would produce a false
- * warning when gsd-sdk is in a machine-level bin dir (e.g. C:\Program Files\nodejs).
- *
- * Returns the filtered persistent Path string (npx segments stripped) or null
- * on any failure (non-Windows, PowerShell not available, spawn timeout, empty
- * result). Callers must treat null as "check unavailable — trust install-time
- * filtered PATH".
- *
- * Synchronous, 2-second timeout, best-effort — safe to call from
- * installSdkIfNeeded without restructuring to async.
- */
-function getUserShellWindowsPersistentPath() {
-  if (process.platform !== 'win32') return null;
-  const cp = require('child_process');
-  // Use the same execFileSync form as getUserShellPath() above — static
-  // literal args, no user input, no injection vector.
-  const execFile = cp.execFileSync.bind(cp);
-  try {
-    // Read Machine + User Path and merge them — the effective PATH that
-    // PowerShell, cmd.exe, and Git Bash inherit is Machine;User (machine
-    // entries first). Reading only User-level Path would produce a false
-    // warning when gsd-sdk is installed in a machine-level bin dir
-    // (e.g. C:\Program Files\nodejs).
-    const out = execFile(
-      'powershell.exe',
-      [
-        '-NoProfile',
-        '-Command',
-        "$u=[Environment]::GetEnvironmentVariable('Path','User');" +
-        "$m=[Environment]::GetEnvironmentVariable('Path','Machine');" +
-        "[Console]::Out.Write(($m + ';' + $u).Trim(';'))",
-      ],
-      {
-        encoding: 'utf8',
-        stdio: ['ignore', 'pipe', 'ignore'],
-        // 2-second cap — a locked registry or slow profile can't hang the install.
-        timeout: 2000,
-      },
-    );
-    // Take the last non-empty line so any motd/banner noise before the output
-    // doesn't corrupt the result — same defensive pattern as getUserShellPath.
-    const lines = String(out || '').split(/\r?\n/).map((s) => s.trim()).filter(Boolean);
-    const candidate = lines.length > 0 ? lines[lines.length - 1] : '';
-    if (!candidate) return null;
-    // Strip transient npx dirs from the persistent Path before returning —
-    // the registry can accumulate stale _npx entries from prior runs.
-    const filtered = filterNpxFromPath(candidate);
-    return filtered.length > 0 ? filtered : null;
-  } catch {
-    return null;
-  }
-}
-
-/**
- * #2775 helper: attempt to materialize the `gsd-sdk` shim at a user-writable
- * PATH location. Returns the absolute path created on success, or null if no
- * suitable location was usable.
- *
- * Strategy (POSIX): prefer ~/.local/bin (creating it if absent — many distros
- * already have it on PATH via .profile). Fall back to the first PATH entry
- * under HOME we can write to. Skip on Windows (npm install -g is the right
- * primitive there; we don't try to fabricate a .cmd shim).
- */
-function trySelfLinkGsdSdk(shimSrc) {
-  if (process.platform === 'win32') {
-    return trySelfLinkGsdSdkWindows(shimSrc);
-  }
-  const path = require('path');
-  const fs = require('fs');
-  const home = os.homedir();
-  if (!home) return null;
-
-  const localBin = path.join(home, '.local', 'bin');
-  const pathCandidates = [];
-  const pathEnv = process.env.PATH || '';
-  for (const seg of pathEnv.split(path.delimiter)) {
-    if (!seg) continue;
-    const abs = path.resolve(seg);
-    if (abs.startsWith(home + path.sep) && !pathCandidates.includes(abs)) {
-      pathCandidates.push(abs);
-    }
-  }
-  // If ~/.local/bin is already on PATH, keep it first (preserves existing UX
-  // for the common case). Otherwise prefer PATH-backed HOME dirs first so we
-  // self-link somewhere actually on PATH, falling back to ~/.local/bin only
-  // when no on-PATH HOME dir is writable. (#2775 CodeRabbit follow-up)
-  const candidates = pathCandidates.includes(localBin)
-    ? [localBin, ...pathCandidates.filter((dir) => dir !== localBin)]
-    : [...pathCandidates, localBin];
-
-  for (const dir of candidates) {
-    try {
-      fs.mkdirSync(dir, { recursive: true });
-      const target = path.join(dir, 'gsd-sdk');
-      // Replace any existing entry — it may be stale (prior install of an
-      // older version pointing at a now-absent shim).
-      try { fs.unlinkSync(target); } catch {}
-      try {
-        fs.symlinkSync(shimSrc, target);
-      } catch {
-        // Filesystems that don't support symlinks (some FUSE mounts): write a
-        // tiny wrapper that `require()`s the real shim by absolute path. We
-        // cannot copyFileSync(shimSrc, target) — bin/gsd-sdk.js resolves the
-        // CLI via `path.resolve(__dirname, '..', 'sdk', 'dist', 'cli.js')`,
-        // and after a copy `__dirname` would be the link directory (e.g.
-        // ~/.local/bin), causing the resolved CLI path to be broken
-        // (~/.local/sdk/dist/cli.js). Wrapping via require() preserves
-        // __dirname resolution because the require runs against shimSrc's
-        // own location. (#2775 CodeRabbit follow-up)
-        fs.writeFileSync(
-          target,
-          `#!/usr/bin/env node\nrequire(${JSON.stringify(shimSrc)});\n`,
-        );
-        try { fs.chmodSync(target, 0o755); } catch {}
-      }
-      return target;
-    } catch {
-      // permission / EROFS — try next candidate.
-    }
-  }
-  return null;
-}
-
-/**
- * #2962: Windows counterpart to trySelfLinkGsdSdk. Prior to this, the function
- * unconditionally returned null on Windows ("we don't try to fabricate a .cmd
- * shim there"), which left `--sdk --global` installs without a callable
- * `gsd-sdk` on PATH despite the installer reporting success.
- *
- * Strategy: discover npm's global bin directory via `npm prefix -g` (which on
- * Windows IS the bin dir, no `bin/` suffix — see line 8721) and write the same
- * three-file shim set npm itself emits: `gsd-sdk.cmd` (cmd.exe), `gsd-sdk.ps1`
- * (PowerShell), and a Bash wrapper named `gsd-sdk` (for Cygwin/MSYS/Git-Bash).
- * Each shim invokes `node "<absolute path to bin/gsd-sdk.js>"` with passed
- * args so the shim location is decoupled from the SDK location — same logical
- * structure as the POSIX wrapper-via-require() fallback above.
- *
- * Returns the .cmd file path on success (the primary handle the installer's
- * onPath check looks for), null otherwise.
- */
-/**
- * Pure builder: compute the structured Windows shim triple from a shimSrc path.
- * No filesystem I/O, no spawn — produces the IR that `trySelfLinkGsdSdkWindows`
- * then renders to disk. Exposed for tests so assertions can run against typed
- * fields (interpreter, shimAbs, eol, fileNames) instead of substring matches
- * over rendered shim text.
- */
+// Projection-contract surfaces (drift guards: tests/bug-3441, tests/bug-3442).
+// These have no production caller after the #505 dead-SDK-verification removal,
+// but they are the install.js side of the shell-command projection contract:
+// the drift-guard tests assert install.js delegates to
+// shell-command-projection.cjs rather than hand-rolling the projection. Kept
+// exported so that contract stays verifiable.
 function buildWindowsShimTriple(shimSrc) {
   return buildWindowsShimTripleFromProjection(shimSrc);
 }
 
-/**
- * #3011: pure builder for the SDK-not-on-PATH diagnostic. Takes the
- * resolved shim directory (or null if write failed), the current platform,
- * and the install.js __dirname (used to detect npx-cache invocation).
- * Returns a typed IR with:
- *   - shimLocationLine: prose mentioning where the shim is (or empty if no
- *     write happened)
- *   - actionLines: ordered list of commands the user can run to add the
- *     shim dir to their PATH (platform-specific shells), or fallback to
- *     `npm install -g` advice when no shim was written
- *   - npxNoteLines: ordered list of lines warning about npx persistence
- *     when runDir is under an `_npx` cache segment
- *
- * Tests assert on the typed fields (paths/commands), not on rendered
- * console output. Pure function — no fs, no spawn, no console.
- */
 function formatSdkPathDiagnostic({ shimDir, platform, runDir }) {
   return formatSdkPathDiagnosticFromProjection({ shimDir, platform, runDir });
 }
 
-function trySelfLinkGsdSdkWindows(shimSrc) {
-  const path = require('path');
-  const fs = require('fs');
-  const cp = require('child_process');
-
-  let npmPrefix;
-  try {
-    // On Windows, `npm` is `npm.cmd` — Node's child_process docs explicitly
-    // call out that .cmd/.bat files cannot be spawned via execFile/execFileSync
-    // without a shell ("Spawning .bat and .cmd files on Windows" section).
-    // Match the existing convention at line ~8718 which uses execSync for the
-    // same `npm prefix -g` lookup. Inputs here are static literals, so shell
-    // interpolation is not an injection vector.
-    npmPrefix = cp
-      .execSync('npm prefix -g', {
-        encoding: 'utf8',
-        stdio: ['ignore', 'pipe', 'ignore'],
-      })
-      .trim();
-  } catch {
-    return null;
-  }
-  if (!npmPrefix || !fs.existsSync(npmPrefix)) return null;
-
-  // Verify writability before producing partial shim sets.
-  try {
-    fs.mkdirSync(npmPrefix, { recursive: true });
-    const probe = path.join(npmPrefix, '.gsd-sdk-write-probe');
-    fs.writeFileSync(probe, '');
-    fs.unlinkSync(probe);
-  } catch {
-    return null;
-  }
-
-  const triple = buildWindowsShimTriple(shimSrc);
-  const targets = {
-    cmd: path.join(npmPrefix, triple.fileNames.cmd),
-    ps1: path.join(npmPrefix, triple.fileNames.ps1),
-    sh: path.join(npmPrefix, triple.fileNames.sh),
-  };
-
-  try {
-    // Replace any existing shims — they may be stale (prior install of an
-    // older version pointing at a now-absent shim path).
-    for (const target of Object.values(targets)) {
-      try { fs.unlinkSync(target); } catch {}
-    }
-    fs.writeFileSync(targets.cmd, triple.render.cmd());
-    fs.writeFileSync(targets.ps1, triple.render.ps1());
-    fs.writeFileSync(targets.sh, triple.render.sh());
-    // chmod is a no-op on Windows-native node but harmless; sets exec bit on
-    // WSL-mounted filesystems where Bash users live.
-    try { fs.chmodSync(targets.sh, 0o755); } catch {}
-    return targets.cmd;
-  } catch {
-    // Partial-write on permission flap — best-effort cleanup so the next run
-    // starts from a clean slate.
-    for (const target of Object.values(targets)) {
-      try { fs.unlinkSync(target); } catch {}
-    }
-    return null;
-  }
-}
-
 /**
  * Install GSD for all selected runtimes
  */
@@ -11729,15 +10931,10 @@ module.exports = {
     install,
     installAllRuntimes,
     uninstall,
-    installSdkIfNeeded,
     detectStaleStandaloneSdk,
     formatStaleStandaloneSdkWarning,
-    buildSdkFailFastReport,
-    renderSdkFailFastReport,
-    buildGsdSdkVersionMismatchReport,
-    renderGsdSdkVersionMismatchReport,
-    classifySdkInstall,
-    readGsdSdkVersion,
+    buildWindowsShimTriple,
+    formatSdkPathDiagnostic,
     convertClaudeCommandToCodexSkill,
     convertClaudeToOpencodeFrontmatter,
     convertClaudeToKiloFrontmatter,
@@ -11788,15 +10985,6 @@ module.exports = {
     populatePristineDir,
     USER_OWNED_ARTIFACTS,
     finishInstall,
-    trySelfLinkGsdSdk,
-    trySelfLinkGsdSdkWindows,
-    buildWindowsShimTriple,
-    formatSdkPathDiagnostic,
-    filterNpxFromPath,
-    isLegacyGsdSdkShim,
-    isGsdSdkOnPath,
-    getUserShellPath,
-    getUserShellWindowsPersistentPath,
     homePathCoveredByRc,
     maybeSuggestPathExport,
     runtimeMap,
diff --git a/tests/bug-3020-install-shell-path-probe.test.cjs b/tests/bug-3020-install-shell-path-probe.test.cjs
deleted file mode 100644
index 96bf6229f..000000000
--- a/tests/bug-3020-install-shell-path-probe.test.cjs
+++ /dev/null
@@ -1,169 +0,0 @@
-/**
- * Regression test for bug #3020.
- *
- * The installer prints `✓ GSD SDK ready (sdk/dist/cli.js)` whenever
- * isGsdSdkOnPath() — which reads process.env.PATH from the install
- * subprocess — finds the shim. That set is not the same as the user's
- * later interactive shell PATH:
- *
- *   - Windows cross-shell: gsd-sdk.cmd resolves under PowerShell/cmd
- *     (PATHEXT) but bare `gsd-sdk` does not resolve under Git Bash /
- *     MSYS / WSL bash.
- *   - POSIX ~/.local/bin: install subprocess inherits npm/npx-injected
- *     PATH containing ~/.local/bin; user's login shell may not.
- *   - Node version managers (nvm/fnm/volta) shim PATH per-shell.
- *
- * Result: green ✓ at install time, "command not found" at workflow
- * runtime (#3011 originals + @x0rk + @stefanoginella).
- *
- * Fix: introduce two helpers and use them at install time.
- *
- *   isGsdSdkOnPath(pathString?: string)
- *     - Now accepts an optional explicit PATH string. When omitted,
- *       falls back to process.env.PATH (preserves existing behavior).
- *     - Pure: no spawn, no I/O beyond fs.statSync on candidates.
- *
- *   getUserShellPath() → string | null
- *     - Probes the user's login shell ($SHELL -lc 'printf %s "$PATH"') on
- *       POSIX so we can predict the runtime shell PATH.
- *     - Returns null on Windows or when the probe fails (caller falls
- *       back to process.env.PATH).
- *
- * Tests are typed-IR / structural — no console capture, no source grep.
- */
-
-'use strict';
-
-process.env.GSD_TEST_MODE = '1';
-
-const { test, describe } = require('node:test');
-const assert = require('node:assert/strict');
-const fs = require('node:fs');
-const os = require('node:os');
-const path = require('node:path');
-
-const INSTALL = require(path.join(__dirname, '..', 'bin', 'install.js'));
-const { isGsdSdkOnPath, getUserShellPath } = INSTALL;
-
-describe('bug #3020: isGsdSdkOnPath accepts an explicit PATH string', () => {
-  test('exported as a function', () => {
-    assert.equal(typeof isGsdSdkOnPath, 'function');
-  });
-
-  test('returns true when an executable gsd-sdk exists in the supplied PATH', () => {
-    const tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-3020-'));
-    try {
-      // Create a fake `gsd-sdk` shim with the executable bit set.
-      const shimName = process.platform === 'win32' ? 'gsd-sdk.cmd' : 'gsd-sdk';
-      const shimPath = path.join(tmp, shimName);
-      fs.writeFileSync(shimPath, process.platform === 'win32' ? '@echo off\nexit 0\n' : '#!/bin/sh\nexit 0\n');
-      if (process.platform !== 'win32') fs.chmodSync(shimPath, 0o755);
-      const result = isGsdSdkOnPath(tmp);
-      assert.equal(result, true, `expected true for PATH=${tmp}, got ${result}`);
-    } finally {
-      fs.rmSync(tmp, { recursive: true, force: true });
-    }
-  });
-
-  test('returns false when the supplied PATH has no gsd-sdk', () => {
-    const tmp = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-3020-'));
-    try {
-      const result = isGsdSdkOnPath(tmp);
-      assert.equal(result, false);
-    } finally {
-      fs.rmSync(tmp, { recursive: true, force: true });
-    }
-  });
-
-  test('zero-arg form preserves existing behavior (reads process.env.PATH)', () => {
-    // Just call it — it shouldn't throw and should return a boolean.
-    const result = isGsdSdkOnPath();
-    assert.equal(typeof result, 'boolean');
-  });
-
-  test('treats an empty PATH string as no segments to scan', () => {
-    const result = isGsdSdkOnPath('');
-    assert.equal(result, false);
-  });
-
-  test('null pathString is type-guarded — falls back to process.env.PATH (#3028 CR)', () => {
-    // Pre-fix: isGsdSdkOnPath(null) threw "Cannot read properties of null
-    // (reading 'split')". Post-fix: typeof check falls back to process.env.PATH.
-    let threw = null;
-    let result;
-    try {
-      result = isGsdSdkOnPath(null);
-    } catch (e) {
-      threw = e;
-    }
-    assert.equal(threw, null, `must not throw on null input, got: ${threw && threw.message}`);
-    assert.equal(typeof result, 'boolean', 'must return a boolean');
-  });
-
-  test('non-string pathString (number, object) falls back to process.env.PATH (#3028 CR)', () => {
-    // Defensive: any non-string argument should fall back, not throw.
-    assert.equal(typeof isGsdSdkOnPath(0), 'boolean');
-    assert.equal(typeof isGsdSdkOnPath({}), 'boolean');
-    assert.equal(typeof isGsdSdkOnPath([]), 'boolean');
-  });
-});
-
-describe('bug #3020: getUserShellPath probes the user login shell PATH', () => {
-  test('exported as a function', () => {
-    assert.equal(typeof getUserShellPath, 'function');
-  });
-
-  test('returns a string with at least one segment OR null', () => {
-    const result = getUserShellPath();
-    if (result === null) {
-      // Acceptable on Windows or when probing fails — caller must fall back.
-      return;
-    }
-    assert.equal(typeof result, 'string');
-    // PATH must have segments separated by the platform delimiter.
-    assert.ok(result.length > 0, 'non-null result must be non-empty');
-  });
-
-  test('returns null on Windows (POSIX shell probe is not portable)', () => {
-    if (process.platform !== 'win32') return;
-    const result = getUserShellPath();
-    assert.equal(result, null);
-  });
-
-  test('returns null when SHELL env var is unset', () => {
-    if (process.platform === 'win32') return;
-    const original = process.env.SHELL;
-    delete process.env.SHELL;
-    try {
-      const result = getUserShellPath();
-      assert.equal(result, null, 'must return null when $SHELL is unset (POSIX caller falls back to process.env.PATH)');
-    } finally {
-      if (original !== undefined) process.env.SHELL = original;
-    }
-  });
-});
-
-describe('bug #3020: cross-shell PATH mismatch is detectable via the new helpers', () => {
-  test('install-time PATH has shim, user-shell PATH does not → mismatch detected', () => {
-    const installDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-3020-install-'));
-    const userDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-3020-user-'));
-    try {
-      const shimName = process.platform === 'win32' ? 'gsd-sdk.cmd' : 'gsd-sdk';
-      const shimPath = path.join(installDir, shimName);
-      fs.writeFileSync(shimPath, process.platform === 'win32' ? '@echo off\nexit 0\n' : '#!/bin/sh\nexit 0\n');
-      if (process.platform !== 'win32') fs.chmodSync(shimPath, 0o755);
-
-      const installSees = isGsdSdkOnPath(installDir);
-      const userSees = isGsdSdkOnPath(userDir);
-
-      assert.equal(installSees, true, 'install-time PATH sees the shim');
-      assert.equal(userSees, false, 'user-shell PATH does not see the shim');
-      // The mismatch is what the post-install check must detect to avoid
-      // the false ✓.
-      assert.notEqual(installSees, userSees, 'shim presence differs between install-time PATH and user-shell PATH');
-    } finally {
-      fs.rmSync(installDir, { recursive: true, force: true });
-      fs.rmSync(userDir, { recursive: true, force: true });
-    }
-  });
-});
diff --git a/tests/bug-505-remove-dead-sdk-verification.test.cjs b/tests/bug-505-remove-dead-sdk-verification.test.cjs
new file mode 100644
index 000000000..2bc760c45
--- /dev/null
+++ b/tests/bug-505-remove-dead-sdk-verification.test.cjs
@@ -0,0 +1,86 @@
+/**
+ * Regression guard for #505: dead SDK-shim verification subsystem removed.
+ *
+ * Post-ADR-0174 the `@opengsd/gsd-sdk` package was retired; `sdk/` no longer
+ * ships. `installSdkIfNeeded` and all functions it transitively called are
+ * dead code with no live callers. This test asserts:
+ *
+ *   1. All removed symbols are NO LONGER exported from bin/install.js.
+ *   2. The two live stale-standalone-SDK helpers (detectStaleStandaloneSdk,
+ *      formatStaleStandaloneSdkWarning) are STILL exported as functions — they
+ *      handle a real user-facing condition (#3406) and MUST NOT be removed.
+ */
+
+'use strict';
+
+process.env.GSD_TEST_MODE = '1';
+
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+
+const inst = require('../bin/install.js');
+
+describe('bug #505: dead SDK verification subsystem removed from bin/install.js', () => {
+  // ----------------------------------------------------------------
+  // Dead symbols — must NOT be exported after removal
+  // ----------------------------------------------------------------
+  const deadSymbols = [
+    'installSdkIfNeeded',
+    'classifySdkInstall',
+    'buildSdkFailFastReport',
+    'renderSdkFailFastReport',
+    'buildGsdSdkVersionMismatchReport',
+    'renderGsdSdkVersionMismatchReport',
+    'readGsdSdkVersion',
+    'parseGsdSdkVersion',
+    'findGsdSdkOnPath',
+    'isGsdSdkOnPath',
+    'isLegacyGsdSdkShim',
+    'trySelfLinkGsdSdk',
+    'trySelfLinkGsdSdkWindows',
+    'filterNpxFromPath',
+    'getUserShellPath',
+    'getUserShellWindowsPersistentPath',
+  ];
+
+  for (const sym of deadSymbols) {
+    test(`dead symbol '${sym}' is not exported`, () => {
+      assert.equal(
+        typeof inst[sym],
+        'undefined',
+        `'${sym}' should have been removed (post #505 dead-code removal) but is still exported as ${typeof inst[sym]}`,
+      );
+    });
+  }
+
+  // ----------------------------------------------------------------
+  // Live symbols — MUST still be exported as functions
+  // ----------------------------------------------------------------
+  test('live function detectStaleStandaloneSdk is still exported', () => {
+    assert.equal(
+      typeof inst.detectStaleStandaloneSdk,
+      'function',
+      'detectStaleStandaloneSdk handles real stale-SDK condition (#3406) and must not be removed',
+    );
+  });
+
+  test('live function formatStaleStandaloneSdkWarning is still exported', () => {
+    assert.equal(
+      typeof inst.formatStaleStandaloneSdkWarning,
+      'function',
+      'formatStaleStandaloneSdkWarning handles real stale-SDK condition (#3406) and must not be removed',
+    );
+  });
+
+  // buildWindowsShimTriple / formatSdkPathDiagnostic have no production caller
+  // after this removal, but they are the install.js side of a projection-contract
+  // drift guard (tests/bug-3441, tests/bug-3442) that assert install.js delegates
+  // to shell-command-projection.cjs. They are deliberately kept exported.
+  test('contract surface buildWindowsShimTriple is still exported', () => {
+    assert.equal(typeof inst.buildWindowsShimTriple, 'function');
+  });
+
+  test('contract surface formatSdkPathDiagnostic is still exported', () => {
+    assert.equal(typeof inst.formatSdkPathDiagnostic, 'function');
+  });
+});
diff --git a/tests/no-unconditional-win32-skip.test.cjs b/tests/no-unconditional-win32-skip.test.cjs
deleted file mode 100644
index ce1a5ea43..000000000
--- a/tests/no-unconditional-win32-skip.test.cjs
+++ /dev/null
@@ -1,70 +0,0 @@
-'use strict';
-
-process.env.GSD_TEST_MODE = '1';
-
-/**
- * Behavior-based regression guard for #2962-class bugs.
- *
- * "Nothing for Windows should be deferred — if it wasn't in, it was missed
- * not deferred." (maintainer guidance, 2026-05-01.)
- *
- * Specifically guards against trySelfLinkGsdSdk silently no-op'ing on
- * Windows. Rather than regex-scanning bin/install.js source (which would
- * fail on harmless refactors and conflicts with the repo's no-source-grep
- * testing standard), this test exercises the function under a simulated
- * `process.platform === 'win32'` and asserts shim files actually land on
- * disk — i.e., the Windows branch dispatches, doesn't early-return null.
- */
-
-const { test, describe, before, after } = require('node:test');
-const assert = require('node:assert/strict');
-const fs = require('node:fs');
-const os = require('node:os');
-const path = require('node:path');
-const cp = require('node:child_process');
-
-const ROOT = path.join(__dirname, '..');
-const installModule = require(path.join(ROOT, 'bin', 'install.js'));
-
-describe('Windows parity guard for trySelfLinkGsdSdk (#2962)', () => {
-  let tmpDir;
-  let origPlatform;
-  let origExecSync;
-
-  before(() => {
-    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-win32-guard-'));
-    origPlatform = process.platform;
-    origExecSync = cp.execSync;
-    // Override process.platform to simulate Windows. process.platform is a
-    // configurable property in Node — Object.defineProperty can swap it.
-    Object.defineProperty(process, 'platform', { value: 'win32', configurable: true });
-    cp.execSync = (cmd) => {
-      if (typeof cmd === 'string' && cmd.trim() === 'npm prefix -g') {
-        return tmpDir + '\n';
-      }
-      throw new Error(`unexpected execSync: ${cmd}`);
-    };
-  });
-
-  after(() => {
-    Object.defineProperty(process, 'platform', { value: origPlatform, configurable: true });
-    cp.execSync = origExecSync;
-    fs.rmSync(tmpDir, { recursive: true, force: true });
-  });
-
-  test('trySelfLinkGsdSdk dispatches to the Windows handler and writes shims (does NOT silently return null)', () => {
-    const shimSrc = path.join(ROOT, 'bin', 'gsd-sdk.js');
-    const result = installModule.trySelfLinkGsdSdk(shimSrc);
-
-    assert.notEqual(
-      result,
-      null,
-      'trySelfLinkGsdSdk must not silently return null on Windows; ' +
-        'a no-op skip is a missed-parity regression (see #2962, #2775).',
-    );
-    assert.ok(
-      fs.existsSync(path.join(tmpDir, 'gsd-sdk.cmd')),
-      'Windows dispatch must materialize gsd-sdk.cmd in the npm global bin',
-    );
-  });
-});