diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index 5f3078b..eeb6749 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -613,11 +613,51 @@ The rotation process:
 
 Plaintext entries are untouched.
 
-### Planned: Multi-Repo + Per-Machine Inclusion (Phase 5)
+### Per-Machine Targeting (Phase 5)
 
-Support for multiple repos on a single server, and per-machine
-inclusion rules (e.g., "this file only applies to Linux machines" or
-"this directory is only for the workstation"). Design TBD.
+Entries can be targeted to specific machines using `only` and `never`
+labels. A machine's identity is a set of labels computed at runtime:
+
+- **Short hostname:** `vade` (before the first dot, lowercased)
+- **OS:** `os:linux`, `os:darwin`, `os:windows` (from `runtime.GOOS`)
+- **Architecture:** `arch:amd64`, `arch:arm64` (from `runtime.GOARCH`)
+- **Tags:** `tag:work`, `tag:server` (from `<repo>/tags`, local-only)
+
+**Manifest fields on Entry:**
+
+```yaml
+files:
+  - path: ~/.bashrc.linux
+    only: [os:linux]            # restore/checkpoint only on Linux
+    ...
+  - path: ~/.ssh/work-config
+    only: [tag:work]            # only on machines tagged "work"
+    ...
+  - path: ~/.config/heavy
+    never: [arch:arm64]         # everywhere except ARM
+    ...
+  - path: ~/.special
+    only: [vade]                # only on host "vade"
+    ...
+```
+
+**Matching rules:**
+- `only` set → entry applies if *any* label matches the machine
+- `never` set → entry excluded if *any* label matches
+- Both set → error (mutually exclusive)
+- Neither set → applies everywhere (current behavior)
+
+**Operations affected:**
+- `restore` — skip non-matching entries
+- `checkpoint` — skip non-matching entries (don't clobber stored version)
+- `status` — report non-matching entries as `skipped`
+- `add`, `list`, `verify`, `diff` — operate on all entries regardless
+
+**Tags file:** `<repo>/tags`, one tag per line, not synced. Each
+machine defines its own tags. `sgard init` adds `tags` to `.gitignore`.
+
+**Label format:** bare string = hostname, `prefix:value` = typed matcher.
+The `tag:` prefix in `only`/`never` maps to bare names in the tags file.
 
 ### Future: Manifest Signing (Phase 6)
 
diff --git a/PROGRESS.md b/PROGRESS.md
index e0f643a..de4c9ec 100644
--- a/PROGRESS.md
+++ b/PROGRESS.md
@@ -42,7 +42,7 @@ ARCHITECTURE.md for design details.
 
 ## Up Next
 
-Phase 5: Multi-Repo + Per-Machine Inclusion (to be planned).
+Phase 5: Per-Machine Targeting (Steps 28–32). Ready for Step 28.
 
 ## Known Issues / Decisions Deferred
 
@@ -91,3 +91,4 @@ Phase 5: Multi-Repo + Per-Machine Inclusion (to be planned).
 | 2026-03-24 | 25 | Real FIDO2: go-libfido2 bindings, build tag gating, CLI wiring, nix sgard-fido2 package. |
 | 2026-03-24 | 26 | Test cleanup: tightened lint, 3 combo tests (encrypted+locked, dir-only+locked, toggle), stale doc fixes. |
 | 2026-03-24 | 27 | Phase 4 polish: e2e test (TLS+encryption+locked+push/pull), final doc review. Phase 4 complete. |
+| 2026-03-24 | — | Phase 5 planned (Steps 28–32): machine identity, targeting, tags, proto update, polish. |
diff --git a/PROJECT_PLAN.md b/PROJECT_PLAN.md
index d599553..3f8dd9d 100644
--- a/PROJECT_PLAN.md
+++ b/PROJECT_PLAN.md
@@ -276,9 +276,45 @@ Depends on Steps 17, 18.
 - [x] E2e test: integration/phase4_test.go covering TLS + encryption + locked files + push/pull
 - [x] Verify: all tests pass, lint clean, both binaries compile
 
-## Phase 5: Multi-Repo + Per-Machine Inclusion
+## Phase 5: Per-Machine Targeting
 
-(To be planned)
+### Step 28: Machine Identity + Targeting Core
+
+- [ ] `manifest/manifest.go`: add `Only []string` and `Never []string` to Entry (yaml tags `only,omitempty` / `never,omitempty`)
+- [ ] `garden/identity.go`: `Identity(repoRoot string) []string` — returns machine's label set: short hostname, `os:<GOOS>`, `arch:<GOARCH>`, `tag:<name>` from `<repo>/tags`
+- [ ] `garden/targeting.go`: `EntryApplies(entry, labels) bool` — match logic: `only` → any match, `never` → no match, error if both set
+- [ ] `garden/tags.go`: `LoadTags(repoRoot)`, `SaveTag(repoRoot, tag)`, `RemoveTag(repoRoot, tag)` — read/write `<repo>/tags` file
+- [ ] `garden/garden.go`: `Init` appends `tags` to `.gitignore`
+- [ ] Tests: identity computation, tag load/save, matching (only, never, both-error, bare hostname, os:, arch:, tag:, neither)
+
+### Step 29: Operations Respect Targeting
+
+- [ ] `garden/garden.go`: `Checkpoint` skips entries where `!EntryApplies`
+- [ ] `garden/garden.go`: `Restore` skips entries where `!EntryApplies`
+- [ ] `garden/garden.go`: `Status` reports `skipped` for non-matching entries (or omits them — TBD)
+- [ ] `garden/garden.go`: `Add` accepts `Only`/`Never` in `AddOptions`
+- [ ] Tests: checkpoint/restore/status skip non-matching, add with targeting
+
+### Step 30: Targeting CLI Commands
+
+- [ ] `cmd/sgard/tag.go`: `sgard tag add <name>`, `sgard tag remove <name>`, `sgard tag list`
+- [ ] `cmd/sgard/identity.go`: `sgard identity` — print full label set
+- [ ] `cmd/sgard/add.go`: `--only` and `--never` flags (comma-separated or repeated)
+- [ ] `cmd/sgard/target.go`: `sgard target <path> --only <labels>`, `--never <labels>`, `--clear`
+- [ ] Tests: tag file CRUD, identity output
+
+### Step 31: Proto + Sync Update
+
+- [ ] `proto/sgard/v1/sgard.proto`: add `repeated string only` and `repeated string never` to ManifestEntry
+- [ ] `server/convert.go`: update proto ↔ manifest conversion
+- [ ] Regenerate proto: `make proto`
+- [ ] Tests: round-trip conversion with targeting fields
+
+### Step 32: Phase 5 Polish
+
+- [ ] Update ARCHITECTURE.md, README.md, CLAUDE.md, PROGRESS.md
+- [ ] E2e test: add entries with targeting, push/pull, restore on different identity
+- [ ] Verify: all tests pass, lint clean, both binaries compile
 
 ## Phase 6: Manifest Signing