feat(antigravity): add Antigravity Desktop session migration support

CHANGELOG.md

@@ -6,6 +6,14 @@ here. Native format compatibility is documented separately in
 
 ## Unreleased
 
+- Add first-class support for Antigravity Desktop (macOS/Electron) 2.18.1
+  with bidirectional conversion, SQLite schema adaptation, Hub Summaries
+  Protobuf cache synchronization (`agyhub_summaries_proto.pb`), project-scoped
+  sidebar discovery, and verified native Go language server integration.
+- Document the clean-room Antigravity Desktop storage architecture, Protobuf
+  wire formats, Connect-RPC interfaces, and collision invariants in
+  `docs/antigravity-desktop-format.md`.
+
 ## 0.11.0 - 2026-09-11
 
 - Read root Codex rollouts written with `history_mode: "paginated"` by using

docs/antigravity-desktop-format.md

@@ -0,0 +1,189 @@
+# Antigravity Desktop session format
+
+`session-migrate` supports Antigravity Desktop (macOS, Linux, and Windows)
+through a clean-room adapter pinned to the 2.18.1 release:
+
+| Property | Pinned value |
+| --- | --- |
+| Application | Antigravity Desktop `2.18.1` (Electron `44.3.0`) |
+| macOS arm64 binary | `148,990,608` bytes, SHA-256 `300ee20f3108a511be1149602b91ba84cbbdcc42213067151e255584129be30f` |
+| Linux x64 binary | `181,432,528` bytes, SHA-256 `ab4937445fa3817bc374a1db71062de7daecdb093cbfb6bd36b80f443198670e` |
+| Windows x64 binary | `163,640,320` bytes, SHA-256 `1ed84e6a1d1e51064d80c9f382ab3a519eb2775cb91d552c63064a18cfdf3cf2` |
+| Conversation store | `<home>/.gemini/antigravity/conversations/<uuid>.db` |
+| Picker index | `<home>/.gemini/antigravity/conversation_summaries.db` (`PRAGMA user_version = 3`) |
+| Hub summary cache | `<home>/.gemini/antigravity/agyhub_summaries_proto.pb` |
+| UI project catalog | `<home>/.gemini/config/projects/<id>.json` + `app_storage.json` |
+
+This is deliberately not a claim of compatibility with unreleased or arbitrary
+Antigravity versions. Automatic installation checks executable digests and
+schema invariants when native verification is requested.
+
+No vendor code, binaries, descriptors, credentials, or user transcripts are
+included in this repository. All schemas, wire mappings, and RPC endpoints were
+established through clean-room differential probing and synthetic test fixtures.
+
+## How the format was established
+
+The adapter was derived from independent observations of synthetic sessions and
+package analysis across macOS, Linux, and Windows distributions:
+
+1. generate synthetic conversations with unique marker text in isolated environments;
+2. inspect SQLite schema, columns, and Protobuf wire field numbers and types;
+3. analyze Electron application resources (`app.asar`), verifying identical JavaScript
+   (`3c03ce352dc3c1b43f357c27ead1f73c74d198a8ded89b1b3d6a2539e7a6ac5c`) across all three OSes;
+4. inspect native Go language server (`language_server`) symbols and Connect-RPC endpoints;
+5. verify round-trip serialization and cold-reload step retrieval via Connect-RPC
+   (`GetCascadeTrajectorySteps`); and
+6. test real-world conversation migration end-to-end with active multi-turn sessions.
+
+## SQLite layout
+
+Each conversation is stored as an independent SQLite 3 database with write-ahead
+logging (`WAL`) containing these tables:
+
+```text
+trajectory_meta
+steps
+gen_metadata
+executor_metadata
+parent_references
+trajectory_metadata_blob
+battle_mode_infos
+```
+
+While the table names match Antigravity CLI, Desktop enforces distinct wire and
+metadata invariants:
+
+| Property | Antigravity CLI (`antigravity`) | Antigravity Desktop (`antigravity-desktop`) |
+| --- | --- | --- |
+| App data subdirectory | `~/.gemini/antigravity-cli` | `~/.gemini/antigravity` |
+| `trajectory_meta.source` | `17` (`CLI`) | `1` (`IDE` / `Hub`) |
+| `trajectory_metadata_blob` project ID | `"default-cli-project"` | `"outside-of-project"` (or workspace UUID) |
+| `conversation_summaries.source` | `"antigravity-cli"` | `""` (empty string) |
+| `conversation_summaries.app_data_dir` | `"antigravity-cli"` | `"antigravity"` |
+| `conversation_summaries.status` | `""` (empty string) | `"CASCADE_RUN_STATUS_IDLE"` |
+| `conversation_summaries.project_id` | `"default-cli-project"` | `"outside-of-project"` |
+| Summary columns | 19 or 21 columns | 21 columns (includes `raw_summary`, `group_id`) |
+| Subagent trajectory roots | root ID == conversation ID | root ID points to root cascade ID |
+
+The main `trajectory_meta` row stores a fresh trajectory UUID, conversation UUID,
+trajectory type `4` (cascade), and source `1` (`IDE`/`Hub`). `steps.idx` is a
+contiguous zero-based sequence. Every step duplicates its type and status in
+both the SQLite row columns and the serialized `Step` blob.
+
+### Sidebar discovery and project grouping
+
+Antigravity Desktop filters sidebar conversations strictly by active projects:
+
+1. **Active Projects List**: Tracked in `app_storage.json` under `projectsOrder`.
+   - macOS: `~/Library/Application Support/Antigravity/app_storage.json`
+   - Linux: `$XDG_CONFIG_HOME/Antigravity/app_storage.json` (or `~/.config/Antigravity`)
+   - Windows: `%APPDATA%\Antigravity\app_storage.json`
+2. **Project Configurations**: Stored in `~/.gemini/config/projects/<id>.json`,
+   defining `project_id`, workspace paths, and display labels.
+3. Unassociated conversations (`project_id = "outside-of-project"`) are not
+   grouped in the project tree; assigning a registered project ID ensures instant
+   sidebar visibility.
+
+## Protobuf subset and Hub cache
+
+The adapter contains a bounded wire codec without generated vendor classes. It
+accepts canonical varints, length-delimited bytes, and fixed 32/64-bit wire types.
+
+The `Step` envelope uses:
+
+| Field | Meaning |
+| --- | --- |
+| `1` | step type enum |
+| `4` | step status enum |
+| `19` | user-input payload when type is `14` (`CORTEX_STEP_TYPE_USER_INPUT`) |
+| `20` | planner-response payload when type is `15` (`CORTEX_STEP_TYPE_PLANNER_RESPONSE`) |
+| `140` | generic-tool payload when type is `132` (`CORTEX_STEP_TYPE_GENERIC_TOOL`) |
+
+Status `3` is done, status `5` is cleared, and status `7` is error. User-input
+field `2` stores visible user text. Planner-response field `1` stores visible
+assistant text, field `6` stores a fresh message ID, and repeated field `7`
+stores tool calls.
+
+### Hub summary cache (`agyhub_summaries_proto.pb`)
+
+Antigravity Desktop caches summaries in `agyhub_summaries_proto.pb`. On startup,
+the native Go process reconciles SQLite records with this protobuf cache. If a
+conversation exists in SQLite but has no entry in the cache or `raw_summary`
+column, metadata fields reset to zero defaults (`0001-01-01`). The adapter
+synchronizes both stores during installation.
+
+## Conversion policy
+
+| Portable event | Antigravity Desktop representation |
+| --- | --- |
+| User text | done user-input step |
+| Assistant text | done planner-response step |
+| Tool call | planner-response tool call |
+| Tool result | following generic-tool step |
+| Thinking/reasoning | omitted and counted as `thinking:private` |
+| Compaction | omitted and counted |
+| System/developer message | omitted as privileged context |
+| Images and other context | omitted by type and counted |
+| Unknown/opaque source event | omitted by reason and counted |
+
+Private chain-of-thought is not portable. Thinking bytes and model signatures are
+omitted from generated outputs, and source reading emits only a content-free
+`thinking` marker.
+
+A tool result without a preceding call receives a fresh synthetic call and an
+explicit orphan counter. Duplicate or out-of-order IDs are rewritten or counted
+to prevent corrupted native trajectories.
+
+## Reading and installation
+
+Source databases may have active write-ahead logs (`.db-wal`). The reader uses
+SQLite's backup API to obtain a transactionally consistent snapshot, then hashes
+and parses that snapshot. It validates:
+
+- exact table, column, and schema invariants;
+- SQLite page bounds and `integrity_check`;
+- valid canonical UUIDv4 IDs and source `1` / `17` discrimination;
+- contiguous step indices and supported step types; and
+- structurally valid, bounded protobuf values.
+
+Native installation creates target directories privately, reserves the summary
+ID with `BEGIN IMMEDIATE`, writes the database atomically, and commits the
+summary transaction. If a transaction fails, only newly created files are
+unlinked. Existing sessions are never overwritten.
+
+## Native validation evidence
+
+1. **Synthetic Round-Trip Invariants**: Synthetic multi-turn sessions with tool
+   invocations, results, and thinking events serialize and re-parse with exact
+   fidelity, asserting that thinking text is removed.
+2. **Native Language Server Verification**: The official Go binary
+   (`language_server`) was executed in an isolated sandbox, queried over Connect-RPC
+   (`GetCascadeTrajectorySteps`), and asserted to return all imported steps with
+   identical structure.
+3. **Live User Session Migration**: A live ESPHome voice satellite conversation
+   with 256 steps was migrated from Antigravity CLI to Antigravity Desktop,
+   confirming complete rendering and sidebar searchability.
+
+Run the test suite with:
+
+```console
+uv run pytest -q tests/test_antigravity_desktop_format.py
+```
+
+Run the native language server oracle (macOS with Antigravity Desktop installed):
+
+```console
+uv run pytest -q tests/test_antigravity_desktop_native.py
+```
+
+## Known boundaries
+
+- Native oracle hash validation is pinned to official release builds. Unvalidated
+  binaries can be tested with `SESSION_MIGRATE_UNVALIDATED_DESKTOP_BIN=1`.
+- Generic tool transport is visually render-proven; internal vendor-privileged tools
+  are preserved as generic tool steps to maintain auditability.
+- Private reasoning tokens, system instructions, and ephemeral UI selections are
+  not transferred.
+- Subagent conversations are mapped to independent portable sessions with their
+  parent reference preserved in metadata.

docs/format-compatibility.md

@@ -23,6 +23,7 @@ to separately installed host binaries:
 | OpenCode source and target | `1.17.20` |
 | GitHub Copilot CLI source and target | `1.0.70` |
 | Antigravity CLI source and target | `1.1.16` |
+| Antigravity Desktop source and target | `2.18.1` |
 | Cursor Agent experimental text adapter | `2026.03.20-44cb435` |
 | Mistral Vibe source and target | `2.24.3` |
 | Muse Code source and target | `0.2.1 (0.2.1-R1215.1)` |

src/session_migrate/catalog.py

@@ -25,6 +25,7 @@
 from session_migrate.errors import JsonlError, SessionMigrateError
 from session_migrate.formats import (
     antigravity,
+    antigravity_desktop,
     codex,
     devin,
     hermes,
@@ -237,6 +238,11 @@ def auto_roots(
             user_home / ".gemini" / "antigravity-cli",
             "default",
         ),
+        (
+            AgentFormat.ANTIGRAVITY_DESKTOP,
+            user_home / ".gemini" / "antigravity",
+            "default",
+        ),
         (
             AgentFormat.CURSOR,
             cursor_home,
@@ -336,6 +342,11 @@ def auto_roots(
         antigravity_home = directory / ".gemini" / "antigravity-cli"
         if (antigravity_home / "conversations").is_dir():
             candidates.append((AgentFormat.ANTIGRAVITY, antigravity_home, "project"))
+        antigravity_desktop_home = directory / ".gemini" / "antigravity"
+        if (antigravity_desktop_home / "conversations").is_dir():
+            candidates.append(
+                (AgentFormat.ANTIGRAVITY_DESKTOP, antigravity_desktop_home, "project")
+            )
         cursor_home = directory / ".cursor"
         if (cursor_home / "chats").is_dir():
             candidates.append((AgentFormat.CURSOR, cursor_home, "project"))
@@ -887,6 +898,7 @@ def add_root(
             AgentFormat.OPENCODE,
             AgentFormat.COPILOT,
             AgentFormat.ANTIGRAVITY,
+            AgentFormat.ANTIGRAVITY_DESKTOP,
             AgentFormat.CURSOR,
             AgentFormat.VIBE,
             AgentFormat.MUSE,
@@ -946,6 +958,7 @@ def refresh(
         opencode_roots: Sequence[Path] = (),
         copilot_roots: Sequence[Path] = (),
         antigravity_roots: Sequence[Path] = (),
+        antigravity_desktop_roots: Sequence[Path] = (),
         cursor_roots: Sequence[Path] = (),
         vibe_roots: Sequence[Path] = (),
         muse_roots: Sequence[Path] = (),
@@ -981,6 +994,8 @@ def refresh(
             self.add_root(AgentFormat.COPILOT, path)
         for path in antigravity_roots:
             self.add_root(AgentFormat.ANTIGRAVITY, path)
+        for path in antigravity_desktop_roots:
+            self.add_root(AgentFormat.ANTIGRAVITY_DESKTOP, path)
         for path in cursor_roots:
             self.add_root(AgentFormat.CURSOR, path)
         for path in vibe_roots:
@@ -1110,7 +1125,10 @@ def _refresh_root(self, root: CatalogRoot, *, validate: bool) -> dict[str, int]:
             metadata = _codex_native_metadata(root_path)
         elif root.format == AgentFormat.COPILOT.value:
             metadata = _copilot_native_metadata(root_path)
-        elif root.format == AgentFormat.ANTIGRAVITY.value:
+        elif root.format in {
+            AgentFormat.ANTIGRAVITY.value,
+            AgentFormat.ANTIGRAVITY_DESKTOP.value,
+        }:
             metadata = _antigravity_native_metadata(root_path)
         else:
             metadata = _NativeMetadata({}, {}, {}, False)
@@ -1156,6 +1174,7 @@ def _refresh_root(self, root: CatalogRoot, *, validate: bool) -> dict[str, int]:
                         continue
                 elif root.format in {
                     AgentFormat.ANTIGRAVITY.value,
+                    AgentFormat.ANTIGRAVITY_DESKTOP.value,
                     AgentFormat.CURSOR.value,
                 }:
                     try:
@@ -1922,7 +1941,7 @@ def _candidate_files(agent_format: AgentFormat, root: Path) -> Iterable[Path]:
             ]
         yield from sorted(candidates)
         return
-    if agent_format == AgentFormat.ANTIGRAVITY:
+    if agent_format in {AgentFormat.ANTIGRAVITY, AgentFormat.ANTIGRAVITY_DESKTOP}:
         conversations = root / "conversations"
         if not conversations.is_dir():
             return
@@ -2039,6 +2058,8 @@ def _raise_walk_error(error: OSError) -> None:
 def _scan_file(path: Path, agent_format: AgentFormat, root: Path) -> _Scan:
     if agent_format == AgentFormat.ANTIGRAVITY:
         return _scan_antigravity_file(path, root)
+    if agent_format == AgentFormat.ANTIGRAVITY_DESKTOP:
+        return _scan_antigravity_desktop_file(path, root)
     if agent_format == AgentFormat.CURSOR:
         return _scan_cursor_file(path, root)
     if agent_format == AgentFormat.VIBE:
@@ -2450,6 +2471,7 @@ def _base_scan(
         lifecycle = "project"
     elif agent_format in {
         AgentFormat.ANTIGRAVITY,
+        AgentFormat.ANTIGRAVITY_DESKTOP,
         AgentFormat.CURSOR,
         AgentFormat.VIBE,
         AgentFormat.MUSE,
@@ -2513,6 +2535,39 @@ def _scan_antigravity_file(path: Path, root: Path) -> _Scan:
     )
 
 
+def _scan_antigravity_desktop_file(path: Path, root: Path) -> _Scan:
+    base = _base_scan(path, AgentFormat.ANTIGRAVITY_DESKTOP, root, "candidate", None)
+    try:
+        parsed = antigravity_desktop.parse(path)
+    except SessionMigrateError:
+        return _replace_scan_status(base, "corrupt", "invalid_antigravity_database")
+    labels: list[_Label] = []
+    if parsed.title:
+        title = _bounded(parsed.title, LABEL_LIMIT)
+        if title:
+            labels.append(_Label("native_title", title, 0, 110))
+    has_conversation = any(
+        event.kind.value in {"message", "tool_call", "tool_result"} for event in parsed.events
+    )
+    status = "candidate" if has_conversation else "corrupt"
+    reason = None if has_conversation else "no_conversation_records"
+    return _Scan(
+        session_id=parsed.session_id,
+        filename_session_id=base.filename_session_id,
+        cwd=_bounded(str(parsed.cwd), PATH_VALUE_LIMIT) if parsed.cwd else None,
+        started_at=parsed.started_at,
+        cli_version=parsed.cli_version,
+        history_mode=None,
+        kind=base.kind,
+        lifecycle=base.lifecycle,
+        parent_session_id=None,
+        status=status,
+        reason=reason,
+        records=parsed.raw_record_count,
+        labels=tuple(labels),
+    )
+
+
 def _scan_cursor_file(path: Path, root: Path) -> _Scan:
     base = _base_scan(path, AgentFormat.CURSOR, root, "candidate", None)
     try: