diff --git a/CONTEXT.md b/CONTEXT.md
index 71788c750..9d1e5672a 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -152,10 +152,10 @@ Module owning install detection for `/gsd:update`. `resolveUpdateContext({ home,
 Module owning which skills and agents are written to runtime config directories at install time (Phase 1) and at runtime via cluster-level toggles (Phase 2). Phase 1: `gsd-core/bin/lib/install-profiles.cjs` defines named profiles (`core`, `standard`, `full`), computes transitive closure over `requires:` frontmatter, stages skills/agents to runtime config dirs, and persists the chosen profile in a `.gsd-profile` marker. Profile resolution precedence: explicit `--profile=` flag > `.gsd-profile` marker > `full`. `--minimal`/`--core-only` are back-compat aliases for `--profile=core`. Phase 2: `gsd-core/bin/lib/surface.cjs` implements the `/gsd:surface` slash command for cluster-level enable/disable without reinstall; cluster definitions live in `gsd-core/bin/lib/clusters.cjs`; per-runtime state persists in `<runtimeConfigDir>/.gsd-surface.json` independent from the `.gsd-profile` marker. See ADR-0011.
 
 ### Runtime Artifact Layout Module
-Module owning the per-runtime mapping from artifact kind to filesystem placement. ADR-3660 defines the typed `kinds` per runtime (`commands`, `agents`, `skills`) with destination subpath, prefix, and stage adapter (with per-runtime converters in `bin/install.js`: `convertClaudeCommandToClaudeSkill`, `…CodexSkill`, `…CopilotSkill`, `…AntigravitySkill`). Owns the per-runtime `nested` skill-bundle decision (#69): a `skillsKind` flag in `src/runtime-artifact-layout.cts` drives whether a runtime receives the nested router layout (6 `gsd-ns-*` routers + concrete skills under `<router>/skills/<name>/`) or the flat `skills/gsd-<stem>/` layout; the evidence/doc-link matrix is recorded in a comment above `resolveRuntimeArtifactLayout`. Phase 1 applies this seam to the Runtime Surface Module (`surface.cjs:applySurface`); as of #813, `applySurface` applies the same per-runtime skill-body path rewrites as `installRuntimeArtifacts` for `skills` kinds — re-surfacing no longer overwrites installed SKILL.md bodies with converter-default `~/.claude` paths. The shared accessor `getInstallExports` (exported from `runtime-artifact-layout.cjs`) is the single-source seam through which `surface.cjs` reaches `computePathPrefix` and `applyRuntimeContentRewritesInPlace`; the resolved `scope` (`'local'`|`'global'`) is now carried on the `Layout` object returned by `resolveRuntimeArtifactLayout` so `applySurface` derives the same `pathPrefix` (global `$HOME` form vs. absolute) as a fresh install. Phase 2 is planned to migrate install/uninstall in `bin/install.js` so all lifecycle sites iterate one shared layout table instead of re-encoding runtime layout logic. This design is intended to remove the #3659 class of omissions. Migrations remain under the Installer Migration Module (ADR-0008). See ADR-3660.
+Module owning the per-runtime mapping from artifact kind to filesystem placement. ADR-3660 defines the typed `kinds` per runtime (`commands`, `agents`, `skills`) with destination subpath, prefix, and stage adapter (with per-runtime converters in `bin/install.js`: `convertClaudeCommandToClaudeSkill`, `…CodexSkill`, `…CopilotSkill`, `…AntigravitySkill`). Owns the per-runtime `nested` skill-bundle decision (#69): a `skillsKind` flag in `src/runtime-artifact-layout.cts` drives whether a runtime receives the nested router layout (6 `gsd-ns-*` routers + concrete skills under `<router>/skills/<name>/`) or the flat `skills/gsd-<stem>/` layout; the evidence/doc-link matrix is recorded in a comment above `resolveRuntimeArtifactLayout`. Phase 1 applies this seam to the Runtime Surface Module (`surface.cjs:applySurface`); as of #813, `applySurface` applies the same per-runtime skill-body path rewrites as `installRuntimeArtifacts` for `skills` kinds — re-surfacing no longer overwrites installed SKILL.md bodies with converter-default `~/.claude` paths. Per ADR-1508 / #1511 the former `getInstallExports`/`loadInstallExports` relay (a `GSD_TEST_MODE`-guarded `require('bin/install.js')` by which `surface.cjs` reached `computePathPrefix`/`applyRuntimeContentRewritesInPlace`) was DELETED from this module; content rewriting now lives in the Runtime Artifact Conversion Module and `surface.cjs:applySurface` calls its `rewriteStagedSkillBodies` directly. The resolved `scope` is still carried on the `Layout` object so `applySurface` derives the same `pathPrefix` (global `$HOME` form vs. absolute) as a fresh install. Phase 2 is planned to migrate install/uninstall in `bin/install.js` so all lifecycle sites iterate one shared layout table instead of re-encoding runtime layout logic. This design is intended to remove the #3659 class of omissions. Migrations remain under the Installer Migration Module (ADR-0008). See ADR-3660.
 
 ### Runtime Artifact Conversion Module
-Sibling Module to Runtime Artifact Layout Module. Owns projection from canonical Claude-authored command/agent/skill markdown into runtime-specific artifact bodies, including converter selection, frontmatter/body normalization, runtime path rewrites, and staged artifact generation. Runtime Artifact Layout remains responsible for filesystem placement (`kind`, destination subpath, prefix, nesting); Runtime Artifact Conversion owns the content Implementation behind that placement seam so install, uninstall/surface parity, and future plugin/package projections stop reaching back through `bin/install.js` for converter functions or `GSD_TEST_MODE`-guarded installer exports. Chosen direction: sibling Module, not an expanded Layout Module, to preserve ADR-3660's narrow placement responsibility while deepening artifact content locality. First slice: relocate only the layout-reached conversion family (`convertClaudeCommandTo*Skill`, converted command-file emitters, `buildKimiAgentArtifacts`) plus the minimal helper closure they need; do not leave helper dependencies in `bin/install.js` because that would preserve the same shallow seam under a new filename. Installer integration decision: `bin/install.js` imports the conversion Module at top level and re-exports the moved names for compatibility; the conversion Module must not import `bin/install.js` or Runtime Artifact Layout, so the dependency direction becomes installer/layout Adapters -> conversion Module, never conversion -> installer. First-slice Interface decision: export the existing compatibility names only; do not introduce a grouped `convertRuntimeArtifact` Interface until after relocation proves byte-for-byte behavior.
+Sibling Module to Runtime Artifact Layout Module. Owns projection from canonical Claude-authored command/agent/skill markdown into runtime-specific artifact bodies, including converter selection, frontmatter/body normalization, runtime path rewrites, and staged artifact generation. Runtime Artifact Layout remains responsible for filesystem placement (`kind`, destination subpath, prefix, nesting); Runtime Artifact Conversion owns the content Implementation behind that placement seam so install, uninstall/surface parity, and future plugin/package projections stop reaching back through `bin/install.js` for converter functions or `GSD_TEST_MODE`-guarded installer exports. Chosen direction: sibling Module, not an expanded Layout Module, to preserve ADR-3660's narrow placement responsibility while deepening artifact content locality. First slice: relocate only the layout-reached conversion family (`convertClaudeCommandTo*Skill`, converted command-file emitters, `buildKimiAgentArtifacts`) plus the minimal helper closure they need; do not leave helper dependencies in `bin/install.js` because that would preserve the same shallow seam under a new filename. Installer integration decision: `bin/install.js` imports the conversion Module at top level and re-exports the moved names for compatibility; the conversion Module must not import `bin/install.js` or Runtime Artifact Layout, so the dependency direction becomes installer/layout Adapters -> conversion Module, never conversion -> installer. First-slice Interface decision: export the existing compatibility names only; do not introduce a grouped `convertRuntimeArtifact` Interface until after relocation proves byte-for-byte behavior. SHIPPED (ADR-1508): the converter family relocated in #1510 Phase 1 (`getDirName`→runtime-name-policy, `processAttribution` here); #1511 Phase 2 moved the content-rewrite engine here in full — `_applyRuntimeRewrites` (per-runtime switch, injected attribution), the staged-content walkers `applyRuntimeContentRewritesInPlace`/`applyRuntimeContentRewritesForCommandsInPlace`, `computePathPrefix` (private; `_computePathPrefix` for tests), and the deep public seam `rewriteStagedSkillBodies`/`rewriteStagedCommandBodies({runtime,configDir,scope,homedir?,platform?,resolveAttribution?})`. `bin/install.js` binds these back (single owner, exports preserved); `getCommitAttribution` stays in `bin/install.js` (impure install-time config I/O) and is injected. The `getInstallExports` relay in Runtime Artifact Layout Module was deleted; the dependency direction installer/layout → conversion (never upward) is now enforced. Source: `gsd-core/bin/lib/runtime-artifact-conversion.cjs` (generated from `src/runtime-artifact-conversion.cts`).
 
 ### Command Roster Module
 Tiny read-only helper Module owning discovery of canonical `commands/gsd/*.md` command stems for artifact conversion and runtime projection. It is a sibling dependency of Runtime Artifact Conversion Module, not part of conversion itself: conversion consumes a roster to safely rewrite `gsd:` / `/gsd-` references, while roster discovery owns filesystem/catalog knowledge. First slice: extract existing `readGsdCommandNames` behavior behind this Module instead of moving it into Runtime Artifact Conversion Module or keeping it as installer-owned state.
diff --git a/bin/install.js b/bin/install.js
index a3877657e..0b2e127b1 100755
--- a/bin/install.js
+++ b/bin/install.js
@@ -593,30 +593,12 @@ if (hasHelp) {
   process.exit(0);
 }
 
-/**
- * Compute the path prefix used for `@file` references in installed command/skill
- * markdown. For global installs into a runtime config dir under $HOME, we
- * normally substitute the home prefix with `$HOME` so paths expand correctly
- * inside double-quoted shell commands. OpenCode is exempt on every platform:
- * its `@file` include syntax does NOT shell-expand `$HOME`, so a literal
- * `@$HOME/...` is treated as a path relative to the config command/ dir, which
- * resolves to `command/$HOME/...` (file not found). For OpenCode we always emit
- * the absolute resolved path. (#2376 Windows, #2831 macOS/Linux.)
- *
- * @param {object} args
- * @param {boolean} args.isGlobal - Global runtime install vs local project
- * @param {boolean} args.isOpencode - Whether the runtime is OpenCode
- * @param {boolean} args.isWindowsHost - process.platform === 'win32'
- * @param {string} args.resolvedTarget - Absolute target dir, forward-slashed
- * @param {string} args.homeDir - User home dir, forward-slashed
- * @returns {string} pathPrefix ending with '/'
- */
-function computePathPrefix({ isGlobal, isOpencode, isWindowsHost: _isWindowsHost, resolvedTarget, homeDir }) {
-  if (isGlobal && resolvedTarget.startsWith(homeDir) && !isOpencode) {
-    return '$HOME' + resolvedTarget.slice(homeDir.length) + '/';
-  }
-  return `${resolvedTarget}/`;
-}
+// computePathPrefix: implementation moved to runtimeArtifactConversion._computePathPrefix
+// (ADR-1508 / #1511 Phase 2 — single owner). The const binding above (~line 638)
+// re-exports it here for call sites and module.exports.
+// Original doc: Compute the path prefix used for `@file` references in installed
+// command/skill markdown. For global installs under $HOME uses $HOME/... form;
+// OpenCode always uses the absolute path (#2376 Windows, #2831 macOS/Linux).
 
 // normalizeNodePath, resolveNodeRunner, resolveBashRunner, referencesHook are
 // now owned by the runtime-hooks-surface module. Import them here so
@@ -636,6 +618,14 @@ const applySettingsJsonHooks = hooksSurface.applySettingsJsonHooks;
 // callers continue to work and there is a single implementation. (All call
 // sites are below this line, so the const binding has no TDZ hazard.)
 const processAttribution = runtimeArtifactConversion.processAttribution;
+// computePathPrefix / applyRuntimeContentRewritesInPlace / applyRuntimeContentRewritesForCommandsInPlace:
+// Single implementations now live in runtimeArtifactConversion (ADR-1508 / #1511 Phase 2).
+// Re-bound here so install.js call sites and exports continue to work unchanged.
+// Local bodies replaced by breadcrumb comments at their original locations.
+// All call sites are below this line → no TDZ hazard.
+const computePathPrefix = runtimeArtifactConversion._computePathPrefix;
+const applyRuntimeContentRewritesInPlace = runtimeArtifactConversion.applyRuntimeContentRewritesInPlace;
+const applyRuntimeContentRewritesForCommandsInPlace = runtimeArtifactConversion.applyRuntimeContentRewritesForCommandsInPlace;
 
 function rewriteLegacyManagedNodeHookCommands(settings, absoluteRunner, opts) {
   return hooksSurface.rewriteLegacyManagedNodeHookCommands(settings, absoluteRunner, opts);
@@ -6667,24 +6657,10 @@ function migrateLegacyDevPreferencesToSkill(targetDir, saved, runtime, scope = '
  * @param {string} pathPrefix  e.g. "~/.codex/" — trailing-slash string
  * @param {boolean} [isGlobal=false]  true when the install is a global (home-dir) install
  */
-function applyRuntimeContentRewritesInPlace(stagedDir, runtime, pathPrefix, isGlobal = false) {
-  if (!fs.existsSync(stagedDir)) return;
-
-  // Walk all SKILL.md files under stagedDir
-  const walkAndRewrite = (dir) => {
-    for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
-      const fullPath = path.join(dir, entry.name);
-      if (entry.isDirectory()) {
-        walkAndRewrite(fullPath);
-      } else if (entry.name.endsWith('.md')) {
-        let content = fs.readFileSync(fullPath, 'utf8');
-        content = _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal);
-        fs.writeFileSync(fullPath, content);
-      }
-    }
-  };
-  walkAndRewrite(stagedDir);
-}
+// applyRuntimeContentRewritesInPlace: walk loop is now owned by
+// runtimeArtifactConversion.applyRuntimeContentRewritesInPlace (ADR-1508 / #1511 Phase 2).
+// The const binding above (~line 629) delegates here. Call sites in installRuntimeArtifacts
+// pass attribution as the 5th arg (getCommitAttribution(runtime)) per the new contract.
 
 /**
  * Apply per-runtime content rewrites to flat .md files in a staged commands dir.
@@ -6702,30 +6678,10 @@ function applyRuntimeContentRewritesInPlace(stagedDir, runtime, pathPrefix, isGl
  * @param {boolean} [isGlobal=false]  true when the install is a global (home-dir) install
  * @returns {string}  path to a temp dir with rewritten files (caller is responsible for cleanup)
  */
-function applyRuntimeContentRewritesForCommandsInPlace(stagedDir, runtime, pathPrefix, isGlobal = false) {
-  if (!fs.existsSync(stagedDir)) return stagedDir;
-  // Always copy to a temp dir — stageSkillsForProfile() returns the original source
-  // dir on full/default profile (skills === '*'), so writing in-place would corrupt the
-  // package source. A temp copy is unconditional to keep the code simple and safe.
-  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-cmd-rewrites-'));
-  try {
-    for (const entry of fs.readdirSync(stagedDir, { withFileTypes: true })) {
-      if (!entry.isFile() || !entry.name.endsWith('.md')) continue;
-      let content = fs.readFileSync(path.join(stagedDir, entry.name), 'utf8');
-      content = _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal);
-      // For augment commands, apply the markdown conversion so tool references
-      // and skill paths use Augment equivalents.
-      if (runtime === 'augment') {
-        content = convertClaudeToAugmentMarkdown(content);
-      }
-      fs.writeFileSync(path.join(tempDir, entry.name), content);
-    }
-  } catch (err) {
-    try { fs.rmSync(tempDir, { recursive: true, force: true }); } catch { /* best-effort */ }
-    throw err;
-  }
-  return tempDir;
-}
+// applyRuntimeContentRewritesForCommandsInPlace: copy+rewrite loop is now owned by
+// runtimeArtifactConversion.applyRuntimeContentRewritesForCommandsInPlace (ADR-1508 / #1511 Phase 2).
+// The const binding above (~line 630) delegates here. Call sites in installRuntimeArtifacts
+// pass attribution as the 5th arg (getCommitAttribution(runtime)) per the new contract.
 
 /**
  * Apply the per-runtime rewrite table to a single content string.
@@ -6737,196 +6693,11 @@ function applyRuntimeContentRewritesForCommandsInPlace(stagedDir, runtime, pathP
  * @param {boolean} [isGlobal=false]  true when the install is a global (home-dir) install
  * @returns {string}
  */
-function _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal = false) {
-  const dirName = getDirName(runtime);
-  const normalizedPathPrefix = pathPrefix.replace(/\/$/, '');
-
-  switch (runtime) {
-    case 'codex':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/~\/\.codex\//g, pathPrefix);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'cline':
-      // Slash forms: both the original ~/.claude/ (safety net) and the stage-time
-      // converted ~/.cline/ (from convertClaudeToCliineMarkdown) → pathPrefix
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/~\/\.cline\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.cline\//g, pathPrefix);
-      // Bare forms (no trailing slash)
-      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/~\/\.cline\b/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.cline\b/g, normalizedPathPrefix);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'cursor':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      // Bare forms (no trailing slash) — use (?![\w-]) instead of \b so that
-      // .claude-plugin / .claudeignore are NOT corrupted (the \b word-boundary
-      // fires between 'e' and '-', which rewrites .claude-plugin → .cursor-plugin).
-      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\.\/\.claude(?![\w-])/g, `./${dirName}`);
-      content = content.replace(/~\/\.cursor\//g, pathPrefix);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'windsurf': {
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      // Bare forms (no trailing slash) — use (?![\w-]) instead of \b so that
-      // .claude-plugin / .claudeignore are NOT corrupted (the \b word-boundary
-      // fires between 'e' and '-', which rewrites .claude-plugin → .devin-plugin).
-      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/~\/\.codeium\/windsurf\//g, pathPrefix);
-      // Stage-1 converter rewrites .claude/skills/ → .devin/skills/ (workspace-relative
-      // form). For global installs the real path is pathPrefix + skills/, so fix that up
-      // here using the real isGlobal flag (threaded from installRuntimeArtifacts scope,
-      // not derived from pathPrefix substring which misclassifies custom config dirs).
-      // For local installs, the relative .devin/ form is correct — leave it. (#1085)
-      if (isGlobal) {
-        content = content.replace(/\.devin\/skills\//g, `${pathPrefix}skills/`);
-        content = content.replace(/\.\/\.devin\//g, pathPrefix);
-        content = content.replace(/~\/\.devin(?![\w-])/g, normalizedPathPrefix);
-        content = content.replace(/\$HOME\/\.devin(?![\w-])/g, normalizedPathPrefix);
-      }
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-    }
-
-    case 'augment':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\.\/\.claude(?![\w-])/g, `./${dirName}`);
-      content = content.replace(/~\/\.augment\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.augment\//g, pathPrefix);
-      content = content.replace(/~\/\.augment(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.augment(?![\w-])/g, normalizedPathPrefix);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'trae':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\.\/\.claude\b/g, `./${dirName}`);
-      content = content.replace(/~\/\.trae\//g, pathPrefix);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'codebuddy':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\.\/\.claude\b/g, `./${dirName}`);
-      // The codebuddy converter rewrites `.claude/` → `.codebuddy/` at stage
-      // time, so `$HOME/.claude/...` arrives here as `$HOME/.codebuddy/...`.
-      // Normalize BOTH the `~/` and `$HOME/` forms (slash + bare) to the install
-      // target so `--config-dir`/local installs don't leak the default home.
-      content = content.replace(/~\/\.codebuddy\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.codebuddy\//g, pathPrefix);
-      content = content.replace(/~\/\.codebuddy\b/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.codebuddy\b/g, normalizedPathPrefix);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'copilot':
-      // Copilot converter handles path rewrites; only attribution here
-      content = processAttribution(content, getCommitAttribution('copilot'));
-      break;
-
-    case 'antigravity':
-      // Antigravity converter handles path rewrites; only attribution here
-      content = processAttribution(content, getCommitAttribution('antigravity'));
-      break;
-
-    case 'claude':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'qwen':
-      // Branding rewrites run before path rewrites to avoid consuming
-      // patterns that the path step would also match.
-      content = content.replace(/CLAUDE\.md/g, 'QWEN.md');
-      content = content.replace(/\bClaude Code\b/g, 'Qwen Code');
-      // Base path rewrites (use ~/ and $HOME/ slash forms first — most specific)
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/~\/\.qwen\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.qwen\//g, pathPrefix);
-      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/~\/\.qwen(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.qwen(?![\w-])/g, normalizedPathPrefix);
-      // Bare relative .claude/ → .qwen/ (residual refs not matched above)
-      content = content.replace(/\.claude\//g, '.qwen/');
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/\.\/\.qwen\//g, `./${dirName}/`);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'hermes':
-      // Branding rewrites run before path rewrites (same rationale as qwen)
-      content = content.replace(/CLAUDE\.md/g, 'HERMES.md');
-      content = content.replace(/\bClaude Code\b/g, 'Hermes Agent');
-      // Base path rewrites
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/~\/\.hermes\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.hermes\//g, pathPrefix);
-      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/~\/\.hermes(?![\w-])/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.hermes(?![\w-])/g, normalizedPathPrefix);
-      // Bare relative .claude/ → .hermes/ (residual refs)
-      content = content.replace(/\.claude\//g, '.hermes/');
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/\.\/\.hermes\//g, `./${dirName}/`);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    case 'kimi':
-      content = content.replace(/~\/\.claude\//g, pathPrefix);
-      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
-      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
-      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
-      content = content.replace(/\.\/\.claude\b/g, `./${dirName}`);
-      content = processAttribution(content, getCommitAttribution(runtime));
-      break;
-
-    default:
-      // Unknown runtime — no rewrites.
-      // OpenCode/Kilo are intentionally absent: their skills are written by
-      // installOpencodeFamilySkills, which applies pathPrefix BEFORE the
-      // command→skill conversion (mirroring copyFlattenedCommands) rather than
-      // rewriting already-converted SKILL.md bodies. See #784.
-      break;
-  }
-
-  return content;
-}
+// _applyRuntimeRewrites: single implementation lives in runtimeArtifactConversion
+// (ADR-1508 / #1511 Phase 2). Bound here so install.js call sites and exports are
+// reference-identical to the conversion module (consistent with the walkers above).
+// All call sites are below this line → no TDZ hazard.
+const _applyRuntimeRewrites = runtimeArtifactConversion._applyRuntimeRewrites;
 
 /**
  * Copy a staged directory's contents into destDir.
@@ -7256,10 +7027,10 @@ function installRuntimeArtifacts(runtime, configDir, scope, resolvedProfile) {
     let stagedForCopy = staged;
     const isGlobal = scope === 'global';
     if (kind.kind === 'skills' || kind.kind === 'kimi-agents') {
-      applyRuntimeContentRewritesInPlace(staged, runtime, pathPrefix, isGlobal);
+      applyRuntimeContentRewritesInPlace(staged, runtime, pathPrefix, isGlobal, getCommitAttribution(runtime));
     } else if (kind.kind === 'commands') {
       // Returns a temp dir with rewritten content so source files are never mutated.
-      stagedForCopy = applyRuntimeContentRewritesForCommandsInPlace(staged, runtime, pathPrefix, isGlobal);
+      stagedForCopy = applyRuntimeContentRewritesForCommandsInPlace(staged, runtime, pathPrefix, isGlobal, getCommitAttribution(runtime));
     }
     // applyRuntimeContentRewritesForCommandsInPlace() returns a fresh mkdtemp dir under
     // os.tmpdir() (gsd-cmd-rewrites-*); remove it once copied so it does not accumulate (#856).
@@ -10022,7 +9793,7 @@ function install(isGlobal, runtime = 'claude', options = {}) {
         if (!entry.isFile() || !entry.name.endsWith('.md')) continue;
         const stem = entry.name.slice(0, -3);
         let content = fs.readFileSync(path.join(gsdSrc, entry.name), 'utf8');
-        content = _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal);
+        content = _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal, getCommitAttribution(runtime));
         content = normalizeAgentBodyForRuntime(content, runtime, cmdNames);
         fs.writeFileSync(path.join(commandsDir, `gsd-${stem}.md`), content);
         cmdCount++;
diff --git a/src/runtime-artifact-conversion.cts b/src/runtime-artifact-conversion.cts
index 422cba86e..ac5c01181 100644
--- a/src/runtime-artifact-conversion.cts
+++ b/src/runtime-artifact-conversion.cts
@@ -17,9 +17,13 @@
  */
 
 import path from 'node:path';
+import os from 'node:os';
+import fs from 'node:fs';
 import commandRoster = require('./command-roster.cjs');
 const { readGsdCommandNames, transformContentToHyphen } = commandRoster;
 const pkg = require('../../../package.json');
+import runtimeNamePolicy = require('./runtime-name-policy.cjs');
+const { getDirName } = runtimeNamePolicy;
 
 
 const colorNameToHex = {
@@ -2095,6 +2099,335 @@ function convertClaudeCommandToKiloSkill(content, skillName) {
 }
 
 
+// ── Rewrite engine — ADR-1508 Phase 2 ───────────────────────────────────────
+// Relocated from bin/install.js (#1511). Behavior is byte-for-behavior identical
+// to the originals; the only change is the injected `attribution` 5th param in
+// _applyRuntimeRewrites (replacing the internal getCommitAttribution() call).
+
+/**
+ * Compute the path prefix for a runtime install.
+ * Global installs under $HOME use $HOME/... form; others use the resolved target.
+ * isOpencode excludes OpenCode (uses ~/.config/opencode which breaks $HOME shorthand).
+ * isWindowsHost is not used today but reserved for future Windows-specific logic.
+ *
+ * @private — exported as `_computePathPrefix` for tests.
+ */
+function computePathPrefix({ isGlobal, isOpencode, isWindowsHost: _isWindowsHost, resolvedTarget, homeDir }) {
+  if (isGlobal && resolvedTarget.startsWith(homeDir) && !isOpencode) {
+    return '$HOME' + resolvedTarget.slice(homeDir.length) + '/';
+  }
+  return `${resolvedTarget}/`;
+}
+
+/**
+ * Apply the per-runtime rewrite table to a single content string.
+ * Relocated from bin/install.js `_applyRuntimeRewrites`.
+ *
+ * The 5th `attribution` param replaces the internal getCommitAttribution() call
+ * so the function is pure (no config I/O). Pass the resolved attribution value
+ * from the installer; pass `undefined` to leave Co-Authored-By lines untouched.
+ *
+ * @private — exported as `_applyRuntimeRewrites` for tests.
+ */
+function _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal = false, attribution = undefined) {
+  const dirName = getDirName(runtime);
+  const normalizedPathPrefix = pathPrefix.replace(/\/$/, '');
+
+  switch (runtime) {
+    case 'codex':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.codex\//g, pathPrefix);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'cline':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.cline\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.cline\//g, pathPrefix);
+      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/~\/\.cline\b/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.cline\b/g, normalizedPathPrefix);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'cursor':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\.\/\.claude(?![\w-])/g, `./${dirName}`);
+      content = content.replace(/~\/\.cursor\//g, pathPrefix);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'windsurf': {
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/~\/\.codeium\/windsurf\//g, pathPrefix);
+      if (isGlobal) {
+        content = content.replace(/\.devin\/skills\//g, `${pathPrefix}skills/`);
+        content = content.replace(/\.\/\.devin\//g, pathPrefix);
+        content = content.replace(/~\/\.devin(?![\w-])/g, normalizedPathPrefix);
+        content = content.replace(/\$HOME\/\.devin(?![\w-])/g, normalizedPathPrefix);
+      }
+      content = processAttribution(content, attribution);
+      break;
+    }
+
+    case 'augment':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\.\/\.claude(?![\w-])/g, `./${dirName}`);
+      content = content.replace(/~\/\.augment\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.augment\//g, pathPrefix);
+      content = content.replace(/~\/\.augment(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.augment(?![\w-])/g, normalizedPathPrefix);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'trae':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\.\/\.claude\b/g, `./${dirName}`);
+      content = content.replace(/~\/\.trae\//g, pathPrefix);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'codebuddy':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\.\/\.claude\b/g, `./${dirName}`);
+      content = content.replace(/~\/\.codebuddy\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.codebuddy\//g, pathPrefix);
+      content = content.replace(/~\/\.codebuddy\b/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.codebuddy\b/g, normalizedPathPrefix);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'copilot':
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'antigravity':
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'claude':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'qwen':
+      content = content.replace(/CLAUDE\.md/g, 'QWEN.md');
+      content = content.replace(/\bClaude Code\b/g, 'Qwen Code');
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/~\/\.qwen\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.qwen\//g, pathPrefix);
+      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/~\/\.qwen(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.qwen(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\.claude\//g, '.qwen/');
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/\.\/\.qwen\//g, `./${dirName}/`);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'hermes':
+      content = content.replace(/CLAUDE\.md/g, 'HERMES.md');
+      content = content.replace(/\bClaude Code\b/g, 'Hermes Agent');
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/~\/\.hermes\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.hermes\//g, pathPrefix);
+      content = content.replace(/~\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/~\/\.hermes(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.hermes(?![\w-])/g, normalizedPathPrefix);
+      content = content.replace(/\.claude\//g, '.hermes/');
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/\.\/\.hermes\//g, `./${dirName}/`);
+      content = processAttribution(content, attribution);
+      break;
+
+    case 'kimi':
+      content = content.replace(/~\/\.claude\//g, pathPrefix);
+      content = content.replace(/\$HOME\/\.claude\//g, pathPrefix);
+      content = content.replace(/\.\/\.claude\//g, `./${dirName}/`);
+      content = content.replace(/~\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\$HOME\/\.claude\b/g, normalizedPathPrefix);
+      content = content.replace(/\.\/\.claude\b/g, `./${dirName}`);
+      content = processAttribution(content, attribution);
+      break;
+
+    default:
+      // Unknown runtime — no rewrites (OpenCode/Kilo handled by their own install path).
+      break;
+  }
+
+  return content;
+}
+
+/**
+ * LOW-LEVEL: In-place fs walk: rewrite all .md files under stagedDir.
+ *
+ * pathPrefix and attribution are passed in (already resolved by the caller).
+ * Single owner of the walk loop — both the high-level rewriteStagedSkillBodies
+ * and the install.js compat wrapper delegate here.
+ *
+ * @param stagedDir    directory of staged skill/agent files
+ * @param runtime      canonical runtime ID
+ * @param pathPrefix   trailing-slash path prefix (e.g. '$HOME/.cursor/')
+ * @param isGlobal     true for global scope installs
+ * @param attribution  Co-Authored-By value (string | null | undefined)
+ */
+function applyRuntimeContentRewritesInPlace(stagedDir, runtime, pathPrefix, isGlobal = false, attribution = undefined) {
+  if (!fs.existsSync(stagedDir)) return;
+
+  const walkAndRewrite = (dir) => {
+    for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+      const fullPath = path.join(dir, entry.name);
+      if (entry.isDirectory()) {
+        walkAndRewrite(fullPath);
+      } else if (entry.name.endsWith('.md')) {
+        let content = fs.readFileSync(fullPath, 'utf8');
+        content = _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal, attribution);
+        fs.writeFileSync(fullPath, content);
+      }
+    }
+  };
+  walkAndRewrite(stagedDir);
+}
+
+/**
+ * LOW-LEVEL: Copy-to-temp then rewrite all .md files.
+ *
+ * pathPrefix and attribution are passed in (already resolved by the caller).
+ * Single owner of the copy+rewrite loop — both the high-level
+ * rewriteStagedCommandBodies and the install.js compat wrapper delegate here.
+ *
+ * IMPORTANT: always copies to a fresh mkdtemp dir — never mutates the source dir
+ * (stageSkillsForProfile returns the source dir on full profile; mutation would
+ * corrupt the package source).
+ *
+ * @param stagedDir    directory of staged flat .md command files
+ * @param runtime      canonical runtime ID
+ * @param pathPrefix   trailing-slash path prefix
+ * @param isGlobal     true for global scope installs
+ * @param attribution  Co-Authored-By value (string | null | undefined)
+ * @returns {string} path to the temp dir (caller is responsible for cleanup)
+ */
+function applyRuntimeContentRewritesForCommandsInPlace(stagedDir, runtime, pathPrefix, isGlobal = false, attribution = undefined) {
+  if (!fs.existsSync(stagedDir)) return stagedDir;
+
+  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-cmd-rewrites-'));
+  try {
+    for (const entry of fs.readdirSync(stagedDir, { withFileTypes: true })) {
+      if (!entry.isFile() || !entry.name.endsWith('.md')) continue;
+      let content = fs.readFileSync(path.join(stagedDir, entry.name), 'utf8');
+      content = _applyRuntimeRewrites(content, runtime, pathPrefix, isGlobal, attribution);
+      if (runtime === 'augment') {
+        content = convertClaudeToAugmentMarkdown(content);
+      }
+      fs.writeFileSync(path.join(tempDir, entry.name), content);
+    }
+  } catch (err) {
+    try { fs.rmSync(tempDir, { recursive: true, force: true }); } catch { /* best-effort */ }
+    throw err;
+  }
+  return tempDir;
+}
+
+/**
+ * HIGH-LEVEL: In-place fs walk: rewrite all .md files under stagedDir for the given runtime.
+ *
+ * Deep public seam (ADR-1508 Phase 2). Derives resolvedTarget/homeDir/isGlobal/pathPrefix/
+ * attribution from opts, then delegates to applyRuntimeContentRewritesInPlace (single walk owner).
+ *
+ * @param stagedDir   directory of staged skill/agent files
+ * @param opts.runtime          canonical runtime ID
+ * @param opts.configDir        runtime config directory (absolute path)
+ * @param opts.scope            'global' | 'local'
+ * @param opts.homedir          optional homedir resolver (injectable for tests; defaults to os.homedir)
+ * @param opts.platform         optional platform string (injectable for tests; defaults to process.platform)
+ * @param opts.resolveAttribution  optional fn(runtime)→string|null|undefined; called once per invocation
+ */
+function rewriteStagedSkillBodies(stagedDir, opts) {
+  const {
+    runtime,
+    configDir,
+    scope = 'global',
+    homedir = () => os.homedir(),
+    platform = process.platform,
+    resolveAttribution,
+  } = opts;
+  if (!fs.existsSync(stagedDir)) return;
+
+  const resolvedTarget = path.resolve(configDir).replace(/\\/g, '/');
+  const homeDir = homedir().replace(/\\/g, '/');
+  const isGlobal = scope === 'global';
+  const isOpencode = runtime === 'opencode';
+  const isWindowsHost = platform === 'win32';
+  const pathPrefix = computePathPrefix({ isGlobal, isOpencode, isWindowsHost, resolvedTarget, homeDir });
+  const attribution = resolveAttribution ? resolveAttribution(runtime) : undefined;
+
+  applyRuntimeContentRewritesInPlace(stagedDir, runtime, pathPrefix, isGlobal, attribution);
+}
+
+/**
+ * HIGH-LEVEL: Copy-to-temp then rewrite all .md files for the given runtime.
+ *
+ * Deep public seam (ADR-1508 Phase 2). Derives resolvedTarget/homeDir/isGlobal/pathPrefix/
+ * attribution from opts, then delegates to applyRuntimeContentRewritesForCommandsInPlace
+ * (single copy+rewrite owner).
+ *
+ * @returns {string} path to the temp dir (caller is responsible for cleanup)
+ */
+function rewriteStagedCommandBodies(stagedDir, opts) {
+  const {
+    runtime,
+    configDir,
+    scope = 'global',
+    homedir = () => os.homedir(),
+    platform = process.platform,
+    resolveAttribution,
+  } = opts;
+  if (!fs.existsSync(stagedDir)) return stagedDir;
+
+  const resolvedTarget = path.resolve(configDir).replace(/\\/g, '/');
+  const homeDir = homedir().replace(/\\/g, '/');
+  const isGlobal = scope === 'global';
+  const isOpencode = runtime === 'opencode';
+  const isWindowsHost = platform === 'win32';
+  const pathPrefix = computePathPrefix({ isGlobal, isOpencode, isWindowsHost, resolvedTarget, homeDir });
+  const attribution = resolveAttribution ? resolveAttribution(runtime) : undefined;
+
+  return applyRuntimeContentRewritesForCommandsInPlace(stagedDir, runtime, pathPrefix, isGlobal, attribution);
+}
+
+// ── End rewrite engine ────────────────────────────────────────────────────────
+
 /**
  * Apply Co-Authored-By attribution policy to file content.
  *   - null      -> remove the Co-Authored-By line and its preceding blank line
@@ -2175,4 +2508,13 @@ export = {
   convertClaudeAgentToCodebuddyAgent,
   convertClaudeAgentToClineAgent,
   convertClaudeAgentToCodexAgent,
+  // #1511 ADR-1508 Phase 2: rewrite engine deep seam
+  // Low-level walkers (pathPrefix + attribution pre-resolved by caller):
+  applyRuntimeContentRewritesInPlace,
+  applyRuntimeContentRewritesForCommandsInPlace,
+  // High-level wrappers (derive pathPrefix + attribution from opts):
+  rewriteStagedSkillBodies,
+  rewriteStagedCommandBodies,
+  _computePathPrefix: computePathPrefix,
+  _applyRuntimeRewrites,
 };
diff --git a/src/runtime-artifact-layout.cts b/src/runtime-artifact-layout.cts
index 6791af886..3adb6c43a 100644
--- a/src/runtime-artifact-layout.cts
+++ b/src/runtime-artifact-layout.cts
@@ -34,39 +34,10 @@ const conversionExports = runtimeArtifactConversion as Record<string, unknown> &
 // In .cts (CommonJS output) files, `require` is available as a global.
 const _require: NodeRequire = require;
 
-// ---------------------------------------------------------------------------
-// Lazy installer exports (avoids GSD_TEST_MODE env mutation at module load)
-// ---------------------------------------------------------------------------
-
-interface InstallExports {
-  computePathPrefix: (opts: { isGlobal: boolean; isOpencode: boolean; isWindowsHost: boolean; resolvedTarget: string; homeDir: string }) => string;
-  applyRuntimeContentRewritesInPlace: (stagedDir: string, runtime: string, pathPrefix: string) => void;
-  [converterName: string]: unknown;
-}
-
-/**
- * Load bin/install.js exports in a test-safe way.
- * Sets GSD_TEST_MODE only for the duration of the require() call and only if
- * it was not already set, restoring the original value in a finally block so
- * the module-level environment is never permanently mutated.
- */
-function loadInstallExports(): InstallExports {
-  const savedTestMode = process.env['GSD_TEST_MODE'];
-  if (savedTestMode === undefined) process.env['GSD_TEST_MODE'] = '1';
-  try {
-    return _require('../../../bin/install.js') as InstallExports;
-  } finally {
-    if (savedTestMode === undefined) delete process.env['GSD_TEST_MODE'];
-    else process.env['GSD_TEST_MODE'] = savedTestMode;
-  }
-}
-
-/** Cache after first successful load. */
-let _installExports: InstallExports | null = null;
-function getInstallExports(): InstallExports {
-  if (!_installExports) _installExports = loadInstallExports();
-  return _installExports;
-}
+// loadInstallExports / getInstallExports / InstallExports removed in ADR-1508
+// / #1511 Phase 2 — removed this module's upward dependency on bin/install.js
+// (the getInstallExports relay). surface.cts now calls
+// runtimeArtifactConversion.rewriteStagedSkillBodies directly.
 
 // ---------------------------------------------------------------------------
 // Types
@@ -494,4 +465,5 @@ function resolveRuntimeArtifactLayoutFromRegistry(
   return { runtime, configDir, scope, kinds };
 }
 
-export = { resolveRuntimeArtifactLayout, resolveRuntimeArtifactLayoutFromRegistry, findInstallSourceRoot, getInstallExports };
+// getInstallExports removed in ADR-1508 / #1511 Phase 2 (last upward .cts→install.js dep).
+export = { resolveRuntimeArtifactLayout, resolveRuntimeArtifactLayoutFromRegistry, findInstallSourceRoot };
diff --git a/src/surface.cts b/src/surface.cts
index bbd04141d..8422a3871 100644
--- a/src/surface.cts
+++ b/src/surface.cts
@@ -30,7 +30,6 @@
 
 import fs from 'node:fs';
 import path from 'node:path';
-import os from 'node:os';
 import { platformWriteSync } from './shell-command-projection.cjs';
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import installProfiles = require('./install-profiles.cjs');
@@ -43,7 +42,9 @@ import { CLUSTERS } from './clusters.cjs';
 import type { ClusterMap } from './clusters.cjs';
 // eslint-disable-next-line @typescript-eslint/no-require-imports
 import runtimeArtifactLayout = require('./runtime-artifact-layout.cjs');
-const { findInstallSourceRoot, getInstallExports } = runtimeArtifactLayout;
+const { findInstallSourceRoot } = runtimeArtifactLayout;
+// eslint-disable-next-line @typescript-eslint/no-require-imports
+import runtimeArtifactConversion = require('./runtime-artifact-conversion.cjs');
 
 const SURFACE_FILE_NAME = '.gsd-surface.json';
 
@@ -305,26 +306,18 @@ function applySurface(runtimeConfigDir: string, layout: Layout, manifest: Map<st
   const resolved = resolveSurface(layout.configDir, skillManifest, clusterMap, registry);
   // Mirror installRuntimeArtifacts: skills kinds get per-runtime path rewrites
   // so SKILL.md bodies reference the install target (pathPrefix), not the
-  // converter's default ~/.claude paths (#813). Computed lazily so command-only
-  // runtimes do not trigger the install.js require.
-  let pathPrefix: string | null = null;
+  // converter's default ~/.claude paths (#813). Delegated to the conversion
+  // module's deep seam (ADR-1508 / #1511 Phase 2) — no attribution resolver
+  // needed here (proven: Co-Authored-By never appears in staged content; see
+  // brief PROVEN KEY FACT). No getInstallExports() call required.
   for (const kind of layout.kinds) {
     const staged = kind.stage(resolved);
     if (kind.kind === 'skills') {
-      const installExports = getInstallExports();
-      if (pathPrefix === null) {
-        const scope = layout.scope ?? 'global';
-        const resolvedTarget = path.resolve(layout.configDir).replace(/\\/g, '/');
-        const homeDir = os.homedir().replace(/\\/g, '/');
-        pathPrefix = installExports.computePathPrefix({
-          isGlobal: scope === 'global',
-          isOpencode: layout.runtime === 'opencode',
-          isWindowsHost: process.platform === 'win32',
-          resolvedTarget,
-          homeDir,
-        });
-      }
-      installExports.applyRuntimeContentRewritesInPlace(staged, layout.runtime, pathPrefix);
+      runtimeArtifactConversion.rewriteStagedSkillBodies(staged, {
+        runtime: layout.runtime,
+        configDir: layout.configDir,
+        scope: layout.scope ?? 'global',
+      });
     }
     const dest = path.join(layout.configDir, kind.destSubpath);
     _syncGsdDir(staged, dest, kind, skillManifest);
diff --git a/tests/enh-1511-rewrite-engine-relocation.test.cjs b/tests/enh-1511-rewrite-engine-relocation.test.cjs
new file mode 100644
index 000000000..74f60f394
--- /dev/null
+++ b/tests/enh-1511-rewrite-engine-relocation.test.cjs
@@ -0,0 +1,296 @@
+'use strict';
+/**
+ * Tests for ADR-1508 Phase 2: rewrite engine relocation to runtime-artifact-conversion.
+ * Issue #1511 — verifies the deep public seam signatures and behavior.
+ *
+ * Tests are behavioral (no source-grep). All filesystem operations use tmp dirs.
+ */
+
+const { describe, test, before } = 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 { cleanup } = require('./helpers.cjs');
+
+let conversion;
+before(() => {
+  process.env['GSD_TEST_MODE'] = '1';
+  conversion = require('../gsd-core/bin/lib/runtime-artifact-conversion.cjs');
+});
+
+// ---------------------------------------------------------------------------
+// _computePathPrefix unit tests
+// ---------------------------------------------------------------------------
+
+describe('_computePathPrefix', () => {
+  test('global under home → $HOME/... form', () => {
+    const prefix = conversion._computePathPrefix({
+      isGlobal: true,
+      isOpencode: false,
+      isWindowsHost: false,
+      resolvedTarget: '/home/u/.cursor',
+      homeDir: '/home/u',
+    });
+    assert.equal(prefix, '$HOME/.cursor/');
+  });
+
+  test('non-global → resolvedTarget/ form', () => {
+    const prefix = conversion._computePathPrefix({
+      isGlobal: false,
+      isOpencode: false,
+      isWindowsHost: false,
+      resolvedTarget: '/project/.cursor',
+      homeDir: '/home/u',
+    });
+    assert.equal(prefix, '/project/.cursor/');
+  });
+
+  test('global opencode skips $HOME shorthand', () => {
+    // OpenCode uses ~/.config/opencode which breaks $HOME shorthand in content
+    const prefix = conversion._computePathPrefix({
+      isGlobal: true,
+      isOpencode: true,
+      isWindowsHost: false,
+      resolvedTarget: '/home/u/.config/opencode',
+      homeDir: '/home/u',
+    });
+    assert.equal(prefix, '/home/u/.config/opencode/');
+  });
+
+  test('global target outside home → resolvedTarget/ form', () => {
+    const prefix = conversion._computePathPrefix({
+      isGlobal: true,
+      isOpencode: false,
+      isWindowsHost: false,
+      resolvedTarget: '/opt/custom-cursor',
+      homeDir: '/home/u',
+    });
+    assert.equal(prefix, '/opt/custom-cursor/');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// _applyRuntimeRewrites with injected attribution
+// ---------------------------------------------------------------------------
+
+describe('_applyRuntimeRewrites — attribution injection', () => {
+  const PREFIX = '$HOME/.cursor/';
+
+  test('attribution=null removes Co-Authored-By line', () => {
+    const content = '# Hello\n\nSome text\n\nCo-Authored-By: Claude\n';
+    const result = conversion._applyRuntimeRewrites(content, 'cursor', PREFIX, true, null);
+    assert.ok(!result.includes('Co-Authored-By:'), 'Co-Authored-By should be removed');
+  });
+
+  test('attribution=undefined leaves Co-Authored-By unchanged', () => {
+    const content = '# Hello\n\nCo-Authored-By: Claude\n';
+    const result = conversion._applyRuntimeRewrites(content, 'cursor', PREFIX, true, undefined);
+    assert.ok(result.includes('Co-Authored-By: Claude'), 'Co-Authored-By should be preserved when attribution=undefined');
+  });
+
+  test('attribution=string replaces Co-Authored-By value', () => {
+    const content = '# Hello\n\nCo-Authored-By: OldName\n';
+    const result = conversion._applyRuntimeRewrites(content, 'cursor', PREFIX, true, 'NewName <new@example.com>');
+    assert.ok(result.includes('Co-Authored-By: NewName <new@example.com>'), 'Co-Authored-By should be replaced');
+  });
+
+  test('cursor runtime replaces ~/.claude/ paths', () => {
+    const content = 'See ~/.claude/skills/ for more info\n';
+    const result = conversion._applyRuntimeRewrites(content, 'cursor', '/home/u/.cursor/', false, undefined);
+    assert.ok(result.includes('/home/u/.cursor/skills/'), 'cursor should replace ~/.claude/ with pathPrefix');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// rewriteStagedSkillBodies — behavioral filesystem test
+// ---------------------------------------------------------------------------
+
+describe('rewriteStagedSkillBodies', () => {
+  test('rewrites .md files in-place for cursor runtime', () => {
+    const stagedDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-test-staged-'));
+    const configDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-test-config-'));
+    try {
+      // Create a skill dir with a SKILL.md referencing ~/.claude/skills/foo
+      // NOTE: the rewrite engine handles path replacement and attribution only.
+      // Bash→Shell conversion is done by the stage-1 skill converter, not the engine.
+      const skillDir = path.join(stagedDir, 'gsd-test-skill');
+      fs.mkdirSync(skillDir, { recursive: true });
+      const content = '# Test\n\nSee ~/.claude/skills/foo\n\nAlso ~/.cursor/skills/bar\n';
+      fs.writeFileSync(path.join(skillDir, 'SKILL.md'), content);
+
+      // Call with injected homedir + platform for determinism
+      conversion.rewriteStagedSkillBodies(stagedDir, {
+        runtime: 'cursor',
+        configDir,
+        scope: 'global',
+        homedir: () => '/home/u',
+        platform: 'linux',
+      });
+
+      const result = fs.readFileSync(path.join(skillDir, 'SKILL.md'), 'utf8');
+      // cursor rewrites ~/.claude/ → pathPrefix
+      // configDir is a tmpdir, not under /home/u, so prefix = resolvedTarget + '/'
+      // Mirror the engine's backslash→slash normalization so the assertion holds on Windows.
+      const resolvedTarget = path.resolve(configDir).replace(/\\/g, '/');
+      assert.ok(result.includes(`${resolvedTarget}/skills/foo`), `Should replace ~/.claude/skills/ with ${resolvedTarget}/skills/`);
+      // cursor also rewrites ~/.cursor/ → pathPrefix
+      assert.ok(result.includes(`${resolvedTarget}/skills/bar`), `Should replace ~/.cursor/skills/ with ${resolvedTarget}/skills/`);
+    } finally {
+      cleanup(stagedDir);
+      cleanup(configDir);
+    }
+  });
+
+  test('with injected homedir: global under home uses $HOME prefix', () => {
+    // Real absolute path so Windows path.resolve does not re-root a POSIX literal onto a drive.
+    // The dir need not exist — the engine only string-processes it.
+    const HOME = path.resolve(os.tmpdir(), 'gsd-1511-fake-home');
+    const configDir = path.join(HOME, '.cursor');
+    const stagedDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-test-staged-'));
+    try {
+      const skillDir = path.join(stagedDir, 'gsd-help');
+      fs.mkdirSync(skillDir, { recursive: true });
+      fs.writeFileSync(path.join(skillDir, 'SKILL.md'), 'Use ~/.claude/skills/ here\n');
+
+      conversion.rewriteStagedSkillBodies(stagedDir, {
+        runtime: 'cursor',
+        configDir,
+        scope: 'global',
+        homedir: () => HOME,
+        platform: process.platform,
+      });
+
+      const result = fs.readFileSync(path.join(skillDir, 'SKILL.md'), 'utf8');
+      assert.ok(result.includes('$HOME/.cursor/skills/'), 'Should use $HOME shorthand when configDir is under homedir');
+    } finally {
+      cleanup(stagedDir);
+    }
+  });
+
+  test('non-existent stagedDir is a no-op', () => {
+    assert.doesNotThrow(() => {
+      conversion.rewriteStagedSkillBodies('/nonexistent/dir', {
+        runtime: 'cursor',
+        configDir: '/tmp/fake',
+        scope: 'global',
+      });
+    });
+  });
+});
+
+// ---------------------------------------------------------------------------
+// rewriteStagedCommandBodies — returns temp dir, does not mutate source
+// ---------------------------------------------------------------------------
+
+describe('rewriteStagedCommandBodies', () => {
+  test('returns a temp dir (not the source dir) with rewritten content', () => {
+    const stagedDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-test-cmd-'));
+    const configDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-test-config-'));
+    let tempDir;
+    try {
+      // NOTE: rewrite engine handles path replacement + attribution, NOT tool renames.
+      fs.writeFileSync(path.join(stagedDir, 'help.md'), '# Help\n\nSee ~/.claude/skills/\n\nSee ~/.cursor/skills/\n');
+
+      tempDir = conversion.rewriteStagedCommandBodies(stagedDir, {
+        runtime: 'cursor',
+        configDir,
+        scope: 'global',
+        homedir: () => '/home/u',
+        platform: 'linux',
+      });
+
+      assert.notEqual(tempDir, stagedDir, 'must return a different dir, never the source');
+      assert.ok(fs.existsSync(tempDir), 'returned tempDir should exist');
+
+      const result = fs.readFileSync(path.join(tempDir, 'help.md'), 'utf8');
+      // Source dir should be unchanged
+      const source = fs.readFileSync(path.join(stagedDir, 'help.md'), 'utf8');
+      assert.ok(source.includes('~/.claude/skills/'), 'source file must not be mutated');
+      // configDir is /tmp/... (not under /home/u), so prefix = resolvedTarget + '/'
+      const resolvedTarget = path.resolve(configDir).replace(/\\/g, '/');
+      assert.ok(result.includes(`${resolvedTarget}/skills/`), 'output should have cursor path rewrite applied');
+      // ~/.cursor/ also rewrites to prefix
+      assert.ok(!result.includes('~/.cursor/'), 'output should have ~/.cursor/ replaced too');
+    } finally {
+      cleanup(stagedDir);
+      cleanup(configDir);
+      if (tempDir && tempDir !== stagedDir) {
+        cleanup(tempDir);
+      }
+    }
+  });
+
+  test('non-existent stagedDir returns stagedDir unchanged (safe)', () => {
+    const result = conversion.rewriteStagedCommandBodies('/nonexistent/dir', {
+      runtime: 'cursor',
+      configDir: '/tmp/fake',
+      scope: 'global',
+    });
+    assert.equal(result, '/nonexistent/dir', 'should return input path unchanged for missing dir');
+  });
+});
+
+// ---------------------------------------------------------------------------
+// Guard: runtime-artifact-layout no longer exports getInstallExports
+// ---------------------------------------------------------------------------
+
+describe('layout module no longer exports getInstallExports', () => {
+  test('getInstallExports is not on the layout module export', () => {
+    process.env['GSD_TEST_MODE'] = '1';
+    const layout = require('../gsd-core/bin/lib/runtime-artifact-layout.cjs');
+    assert.equal(
+      typeof layout.getInstallExports,
+      'undefined',
+      'getInstallExports should have been removed from runtime-artifact-layout exports (ADR-1508 Phase 2)',
+    );
+  });
+});
+
+// ---------------------------------------------------------------------------
+// DEFECT.GENERATIVE-FIX: single-owner reference-identity guard (#1511)
+// Proves install.js binds to the conversion module's implementation, not a
+// duplicate local copy. If these fail, a duplicate body was re-introduced.
+// ---------------------------------------------------------------------------
+
+describe('single-owner reference-identity guard (ADR-1508 / #1511 Phase 2)', () => {
+  let install;
+  let conversionCjs;
+  before(() => {
+    process.env['GSD_TEST_MODE'] = '1';
+    install = require('../bin/install.js');
+    conversionCjs = require('../gsd-core/bin/lib/runtime-artifact-conversion.cjs');
+  });
+
+  test('install.computePathPrefix === conversion._computePathPrefix (single implementation)', () => {
+    assert.strictEqual(
+      install.computePathPrefix,
+      conversionCjs._computePathPrefix,
+      'install.js must bind computePathPrefix from conversion (not a duplicate body)',
+    );
+  });
+
+  test('install.applyRuntimeContentRewritesInPlace === conversion.applyRuntimeContentRewritesInPlace (single walk loop)', () => {
+    assert.strictEqual(
+      install.applyRuntimeContentRewritesInPlace,
+      conversionCjs.applyRuntimeContentRewritesInPlace,
+      'install.js must bind applyRuntimeContentRewritesInPlace from conversion (not a duplicate walk loop)',
+    );
+  });
+
+  test('install.applyRuntimeContentRewritesForCommandsInPlace === conversion.applyRuntimeContentRewritesForCommandsInPlace (single copy+rewrite loop)', () => {
+    assert.strictEqual(
+      install.applyRuntimeContentRewritesForCommandsInPlace,
+      conversionCjs.applyRuntimeContentRewritesForCommandsInPlace,
+      'install.js must bind applyRuntimeContentRewritesForCommandsInPlace from conversion (not a duplicate copy+rewrite loop)',
+    );
+  });
+
+  test('install._applyRuntimeRewrites === conversion._applyRuntimeRewrites (single switch engine)', () => {
+    assert.strictEqual(
+      install._applyRuntimeRewrites,
+      conversionCjs._applyRuntimeRewrites,
+      'install.js must bind _applyRuntimeRewrites from conversion (not a local shim)',
+    );
+  });
+});