diff --git a/AGENTS.md b/AGENTS.md
index 4c2c9f3..70ae17b 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -83,9 +83,12 @@ entries and opencode loads the plugin twice. An incoming `name@spec` entry
 therefore replaces every existing entry with the same package name, in place
 (`specName` in `src/merge.ts`), and stacked configs collapse on next install.
 `[name@spec, {options}]` tuples count as the same package as the plain string.
-Non-`name@spec` entries (`{{cache}}` fetch dests, prompted dirs, git URLs with
-credentials) stay plain append — a heuristic there would delete unrelated
-entries. `remove` is untouched: it still deletes only exact matches.
+Versioned `{{cache}}` fetch dests supersede too: same path with the `X.Y.Z`
+token blanked = same entry (`cacheFamily`). Only under the cache dir — we own
+it. Prompted dirs, hand-added paths, git URLs with credentials stay plain
+append — a heuristic there would delete unrelated entries. Renaming a dest
+family (`planify-*` → `opencode-planify-german-*`) still stacks once.
+`remove` is untouched: it still deletes only exact matches.
 
 ## Merge stays additive
 
diff --git a/src/batch.ts b/src/batch.ts
index 21fcd67..b432813 100644
--- a/src/batch.ts
+++ b/src/batch.ts
@@ -251,7 +251,7 @@ export async function runBatch(opts: RunBatchOpts): Promise<void> {
       ? new Set(Object.keys(beforeThisModule))
       : new Set<string>();
 
-    const { next, stats } = applyAtPath(working, fullPath, fullBody, m.meta.mode);
+    const { next, stats } = applyAtPath(working, fullPath, fullBody, m.meta.mode, { cacheDir });
     working = next;
 
     let preservedBatch = 0;
diff --git a/src/merge.ts b/src/merge.ts
index 7302093..d047da9 100644
--- a/src/merge.ts
+++ b/src/merge.ts
@@ -11,7 +11,10 @@
 //                       and missing incoming entries are appended. Idempotent.
 //                       An incoming `name@spec` entry supersedes every existing
 //                       entry naming the same package, rather than stacking a
-//                       second version of it alongside the first.
+//                       second version of it alongside the first. Same for a
+//                       versioned path under the cache dir (a `@fetch` dest).
+
+import { sep } from 'node:path';
 
 export type MergeMode = 'replace' | 'merge' | 'merge-overwrite' | 'append';
 
@@ -38,14 +41,15 @@ export function applyAtPath(
   root: Json,
   dottedPath: string,
   value: Json,
-  mode: MergeMode = 'replace'
+  mode: MergeMode = 'replace',
+  opts: { cacheDir?: string } = {}
 ): { next: JsonObject; stats: ApplyStats } {
   const segments = parsePath(dottedPath);
   const next: JsonObject =
     root === undefined || root === null ? {} : (structuredClone(root) as JsonObject);
 
   if (segments.length === 0) {
-    const { value: merged, stats } = combine(next, value, mode);
+    const { value: merged, stats } = combine(next, value, mode, opts.cacheDir);
     return { next: merged as JsonObject, stats };
   }
 
@@ -57,7 +61,7 @@ export function applyAtPath(
   }
   const last = segments[segments.length - 1];
 
-  const { value: combined, stats } = combine(cursor[last], value, mode);
+  const { value: combined, stats } = combine(cursor[last], value, mode, opts.cacheDir);
   cursor[last] = combined;
   return { next, stats };
 }
@@ -66,9 +70,9 @@ export function applyAtPath(
 // `@scope/pkg@1.2.3`, `superpowers@git+https://…#v6.3.0`. opencode loads every
 // entry in the array, so two specs naming the same package load that plugin
 // twice at two versions; append mode uses this to supersede instead of stack.
-// Anything that is not a `name@spec` string returns null and keeps the plain
-// append behaviour: a `{{cache}}` fetch destination, a prompted directory, or a
-// git URL carrying credentials (`git+https://user@host/…`), whose trailing `@`
+// Anything that is not a `name@spec` string returns null: a `{{cache}}` fetch
+// destination (see cacheFamily), a prompted directory, or a git URL carrying
+// credentials (`git+https://user@host/…`), whose trailing `@`
 // would otherwise split in the wrong place.
 // opencode also accepts `[name@spec, {options}]` for a plugin with options; the
 // spec inside names the same package, so a tuple and a plain string supersede
@@ -84,7 +88,43 @@ function specName(value: Json): string | null {
   return name;
 }
 
-function combine(existing: Json, incoming: Json, mode: MergeMode): { value: Json; stats: ApplyStats } {
+// The family of a versioned `@fetch` destination: `<cache>/pkg-rules-0.4.0.md`
+// and `<cache>/pkg-rules-0.3.2.md` share one. AGENTS.md mandates a versioned
+// dest filename, so without this every preset bump stacks another
+// `instructions` or `skills.paths` entry and opencode loads both. Only paths
+// under the cache dir qualify: opencode-presets owns it, so the version
+// heuristic cannot reach a prompted directory or a hand-added path that merely
+// looks versioned.
+// The pre-release suffix is limited to known tags: a generic `-[\w.]+` would eat
+// the extension (`-0.5.0-rc.1.md` vs `-0.4.0.md` stop matching) and fold
+// `tool-1.0.0-linux.tar` and `tool-1.0.0-darwin.tar` into one family.
+const VERSION_TOKEN = /\d+\.\d+\.\d+(?:-(?:alpha|beta|rc|pre|next|dev)(?:\.?\d+)?)?/;
+
+function cacheFamily(value: Json, cacheDir: string | undefined): string | null {
+  if (!cacheDir || typeof value !== 'string') return null;
+  const root = cacheDir.endsWith(sep) || cacheDir.endsWith('/') ? cacheDir.slice(0, -1) : cacheDir;
+  // `{{cache}}/x` is expanded by plain substitution, so on Windows the
+  // separator after the cache dir is `/`, not `sep`.
+  if (!value.startsWith(root) || (value[root.length] !== '/' && value[root.length] !== sep)) return null;
+  const tail = value.slice(root.length + 1);
+  if (!VERSION_TOKEN.test(tail)) return null;
+  return root + '/' + tail.replace(VERSION_TOKEN, '<version>');
+}
+
+// Entries sharing an identity are versions of one thing; append keeps one.
+function identity(value: Json, cacheDir: string | undefined): string | null {
+  const pkg = specName(value);
+  if (pkg !== null) return 'pkg:' + pkg;
+  const family = cacheFamily(value, cacheDir);
+  return family === null ? null : 'cache:' + family;
+}
+
+function combine(
+  existing: Json,
+  incoming: Json,
+  mode: MergeMode,
+  cacheDir?: string
+): { value: Json; stats: ApplyStats } {
   const stats: ApplyStats = { mode, added: 0, preserved: 0, overwritten: 0, superseded: 0, replaced: false };
 
   if (mode === 'append') {
@@ -96,13 +136,13 @@ function combine(existing: Json, incoming: Json, mode: MergeMode): { value: Json
     }
     const target: Json[] = Array.isArray(existing) ? [...existing] : [];
     for (const v of incoming) {
-      const name = specName(v);
+      const name = identity(v, cacheDir);
       // The first entry naming the same package anchors the position. Look it
       // up before the deep-equality check: a config holding both `pkg@0.8.1`
       // and `pkg@0.9.0` must still collapse when `pkg@0.9.0` is installed, and
       // an equality-first check would call that a preserved no-op and leave the
       // stale entry behind.
-      const at = name === null ? -1 : target.findIndex(existingValue => specName(existingValue) === name);
+      const at = name === null ? -1 : target.findIndex(existingValue => identity(existingValue, cacheDir) === name);
       if (at === -1) {
         if (target.some(existingValue => deepEqual(existingValue, v))) {
           stats.preserved++;
@@ -122,7 +162,7 @@ function combine(existing: Json, incoming: Json, mode: MergeMode): { value: Json
         stats.superseded++;
       }
       for (let i = target.length - 1; i > at; i--) {
-        if (specName(target[i]) === name) {
+        if (identity(target[i], cacheDir) === name) {
           target.splice(i, 1);
           stats.superseded++;
         }
diff --git a/test/merge.test.ts b/test/merge.test.ts
index 910a6f7..a5374ac 100644
--- a/test/merge.test.ts
+++ b/test/merge.test.ts
@@ -1,5 +1,6 @@
 import { test, describe } from 'node:test';
 import assert from 'node:assert/strict';
+import { join, sep } from 'node:path';
 import { applyAtPath, removeAtPath, getAtPath } from '../src/merge.js';
 
 describe('applyAtPath — replace mode', () => {
@@ -175,15 +176,89 @@ describe('applyAtPath — append mode', () => {
     assert.equal(stats.superseded, 1);
   });
 
-  // Only `name@spec` entries carry a package identity. A fetched skill path or
-  // a prompted directory must keep the plain additive behaviour, or unrelated
-  // entries sharing a prefix would silently delete each other.
-  test('leaves non-package entries to plain append', () => {
-    const root = { skill: ['{{cache}}/planify-skills-0.3.2'] };
-    const { next, stats } = applyAtPath(root, 'skill', ['{{cache}}/planify-skills-0.4.0'], 'append');
-    assert.deepEqual((next as any).skill, ['{{cache}}/planify-skills-0.3.2', '{{cache}}/planify-skills-0.4.0']);
-    assert.equal(stats.added, 1);
-    assert.equal(stats.superseded, 0);
+  // A versioned `@fetch` dest is a new path on every bump; opencode loads every
+  // `instructions` and `skills.paths` entry, so the old one must go.
+  describe('versioned cache paths', () => {
+    const cacheDir = join(sep, 'home', 'u', '.cache', 'opencode-presets');
+    const at = (p: string) => join(cacheDir, p);
+    const opts = { cacheDir };
+
+    test('supersede an older version in place', () => {
+      const root = { skills: { paths: ['/home/u/diagram-design', at('planify-skills-0.3.2')] } };
+      const { next, stats } = applyAtPath(root, 'skills.paths', [at('planify-skills-0.4.0')], 'append', opts);
+      assert.deepEqual((next as any).skills.paths, ['/home/u/diagram-design', at('planify-skills-0.4.0')]);
+      assert.equal(stats.added, 0);
+      assert.equal(stats.superseded, 1);
+    });
+
+    test('collapse a config that already stacked several versions', () => {
+      const root = { instructions: [at('planify-rules-0.3.1.md'), '/x/AGENTS.md', at('planify-rules-0.3.2.md')] };
+      const { next } = applyAtPath(root, 'instructions', [at('planify-rules-0.4.0.md')], 'append', opts);
+      assert.deepEqual((next as any).instructions, [at('planify-rules-0.4.0.md'), '/x/AGENTS.md']);
+    });
+
+    test('reinstalling the same version stays a preserved no-op', () => {
+      const root = { instructions: [at('planify-rules-0.4.0.md')] };
+      const { next, stats } = applyAtPath(root, 'instructions', [at('planify-rules-0.4.0.md')], 'append', opts);
+      assert.deepEqual((next as any).instructions, [at('planify-rules-0.4.0.md')]);
+      assert.equal(stats.preserved, 1);
+      assert.equal(stats.superseded, 0);
+    });
+
+    test('different families in the cache dir do not touch each other', () => {
+      const root = { p: [at('planify-rules-0.4.0.md')] };
+      const { next } = applyAtPath(root, 'p', [at('planify-skills-0.4.0')], 'append', opts);
+      assert.deepEqual((next as any).p, [at('planify-rules-0.4.0.md'), at('planify-skills-0.4.0')]);
+    });
+
+    // Outside the cache dir a path is the user's (a prompted dir, a hand-added
+    // entry); a version-looking name there is no evidence it is ours to delete.
+    test('leave versioned paths outside the cache dir to plain append', () => {
+      const root = { p: ['/home/u/tools-1.0.0'] };
+      const { next, stats } = applyAtPath(root, 'p', ['/home/u/tools-2.0.0'], 'append', opts);
+      assert.deepEqual((next as any).p, ['/home/u/tools-1.0.0', '/home/u/tools-2.0.0']);
+      assert.equal(stats.superseded, 0);
+    });
+
+    test('leave unversioned cache paths to plain append', () => {
+      const root = { p: [at('rules-a.md')] };
+      const { next } = applyAtPath(root, 'p', [at('rules-b.md')], 'append', opts);
+      assert.deepEqual((next as any).p, [at('rules-a.md'), at('rules-b.md')]);
+    });
+
+    test('a sibling dir sharing the cache dir as a name prefix is not the cache', () => {
+      const root = { p: [join(cacheDir + '-old', 'x-1.0.0')] };
+      const { next } = applyAtPath(root, 'p', [join(cacheDir + '-old', 'x-2.0.0')], 'append', opts);
+      assert.equal((next as any).p.length, 2);
+    });
+
+    test('a pre-release keeps the extension and supersedes both ways', () => {
+      const up = applyAtPath({ p: [at('rules-0.4.0.md')] }, 'p', [at('rules-0.5.0-rc.1.md')], 'append', opts);
+      assert.deepEqual((up.next as any).p, [at('rules-0.5.0-rc.1.md')]);
+      const down = applyAtPath(up.next, 'p', [at('rules-0.5.0.md')], 'append', opts);
+      assert.deepEqual((down.next as any).p, [at('rules-0.5.0.md')]);
+    });
+
+    test('same version, different platform suffix, are different entries', () => {
+      const root = { p: [at('tool-1.0.0-linux.tar')] };
+      const { next, stats } = applyAtPath(root, 'p', [at('tool-1.0.0-darwin.tar')], 'append', opts);
+      assert.deepEqual((next as any).p, [at('tool-1.0.0-linux.tar'), at('tool-1.0.0-darwin.tar')]);
+      assert.equal(stats.superseded, 0);
+    });
+
+    // `{{cache}}/x` is plain substitution, so the separator after the cache
+    // dir is always `/`, whatever the platform separator is.
+    test('a `/` after the cache dir matches regardless of platform', () => {
+      const root = { p: [cacheDir + '/rules-0.3.2.md'] };
+      const { next } = applyAtPath(root, 'p', [cacheDir + '/rules-0.4.0.md'], 'append', opts);
+      assert.deepEqual((next as any).p, [cacheDir + '/rules-0.4.0.md']);
+    });
+
+    test('without a cacheDir, paths keep plain append', () => {
+      const root = { p: [at('planify-skills-0.3.2')] };
+      const { next } = applyAtPath(root, 'p', [at('planify-skills-0.4.0')], 'append');
+      assert.equal((next as any).p.length, 2);
+    });
   });
 
   // `git+https://user@host/...` has a trailing `@` that does not split a