# MsgLib read-only sidecar contract

Date: 2026-07-10

## Purpose

`MsgLibReadSidecar` is the bounded 32-bit .NET process used by the Go MCP layer to access copied or operator-local `MsgLib.db` files through the client-compatible `System.Data.SQLite` provider.

It exists because C26 proved the database opens with the bundled 32-bit SQLite provider and password `123`, while a 64-bit probe fails at provider loading. Go should coordinate the process; the sidecar owns only the narrow Windows/.NET DB read boundary.

## Protocol

- Protocol id: `isphere.msglib.v1`
- Transport: one JSON request on stdin, one JSON response on stdout.
- Process architecture: x86.
- Database mode: read-only only.
- Raw rows: never returned.
- Message bodies: returned only when a future caller explicitly sets `list_messages.include_body=true`; current verification and MCP defaults keep it `false`.
- DB mutation: never allowed.

Request envelope:

```json
{
  "protocol": "isphere.msglib.v1",
  "request_id": "example-1",
  "op": "self_check",
  "args": {}
}
```

Response envelope:

```json
{
  "protocol": "isphere.msglib.v1",
  "request_id": "example-1",
  "op": "self_check",
  "ok": true,
  "data": {},
  "error": null,
  "warnings": []
}
```

## Operations

### `self_check`

Returns sidecar identity, protocol, runtime, process bitness, and capability flags.

Key response fields:

- `sidecar_name`
- `sidecar_version`
- `protocol`
- `runtime`
- `process_bits`
- `requires_process_bits`
- `db_mutation_allowed=false`
- `message_body_reads_allowed=true` for explicit `list_messages.include_body` opt-in; verification keeps it disabled.

### `schema_summary`

Validates provider load and read-only DB open, then returns schema metadata only.

Required args:

- `sqlite_dll_path`: path to bundled `System.Data.SQLite.dll`.
- `db_path`: path to a copied/operator-local `MsgLib.db`.

Optional args:

- `password`: default `123`.
- `include_counts`: default `true`; returns row counts only for target tables.
- `max_tables`: default `128`, clamped to `1..256`.
- `target_tables`: optional list; defaults to known display/message/file metadata tables.

Returned data:

- `metadata_only=true`
- `read_only=true`
- `message_body_values_returned=false`
- `sqlite_version`
- `tables`: table/view names only.
- `columns`: table column names/types only.
- `target_row_counts`: safe row counts for target tables only.

### `display_sources`

Same safe provider/DB validation as `schema_summary`, but additionally maps schema availability to product-facing display source candidates.

Returned data adds:

- `display_sources[]` entries with:
  - `source`
  - `table`
  - `available`
  - `required_columns`
  - `present_columns`

Initial display sources:

- `contacts_roster` from `TD_Roster`.
- `contacts_effigy` from `TD_CustomEffigy`.
- `recent_display` from `tblRecent`.
- `person_message_names` from `tblPersonMsg`.
- `group_message_names` from `tblMsgGroupPersonMsg`.
- `work_group_auth` from `TD_WorkGroupAuth`.
- `received_file_metadata` from `TD_ReceiveFileRecord`.
- `sent_file_metadata` from `TD_SendFileRecord`.

### `display_entities`

Same safe provider/DB validation as `display_sources`, but returns bounded normalized contact/group display metadata.

Required args:

- `sqlite_dll_path`
- `db_path`
- `entity_type`: `contacts` or `groups`

Optional args:

- `password`: default `123`.
- `query`: optional string matched against allowlisted jid/name columns.
- `limit`: bounded to `1..100`; default `25`.

Returned data adds:

- `metadata_only=true`
- `read_only=true`
- `message_body_values_returned=false`
- `raw_rows_returned=false`
- `entities[]` entries with:
  - `entity_type`
  - `source_table`
  - `jid`
  - `display_name`
  - `confidence`
  - `matched_columns`

Initial allowlisted identity sources:

- Contacts: `TD_Roster(JId,Nick)`, `TD_CustomEffigy(PersonJid,PersonName)`, `tblRecent(PersonId,PersonName)`, `tblChatLevel(PersonId,PersonName)`, selected `tblPersonMsg` id/name pairs only.
- Groups: `TD_WorkGroupAuth(GroupJID,GroupName)`, `TD_WorkGroupAuth(ChildGroupJid,GroupName)`, selected `tblMsgGroupPersonMsg` group/session id/name pairs only.

### `message_sources`

Same safe provider/DB validation as `display_sources`, but reports whether candidate message tables are ready for a future DB-backed `isphere_receive_messages` source.

Required args:

- `sqlite_dll_path`
- `db_path`

Optional args:

- `password`: default `123`.

Returned data adds:

- `metadata_only=true`
- `read_only=true`
- `message_body_values_returned=false`
- `raw_rows_returned=false`
- `file_paths_returned=false`
- `message_sources[]` entries with:
  - `source`
  - `table`
  - `role`
  - `available`
  - `required_columns`
  - `present_columns`
  - `row_count`

Initial message source candidates:

- `direct_messages` from `tblPersonMsg`.
- `group_messages` from `tblMsgGroupPersonMsg`.
- `system_messages` from `TD_SystemMessageRecord`.
- `group_receipts` from `TD_GroupReceiptMessage`.
- `received_file_metadata` from `TD_ReceiveFileRecord`.
- `recent_conversation_index` from `tblRecent`.

### `list_messages`

Same safe provider/DB validation as `message_sources`, but returns a bounded normalized message list for future DB-backed receive-message work. C38 keeps this at sidecar/Go-wrapper level only; it is not wired into MCP receive by default.

Required args:

- `sqlite_dll_path`
- `db_path`

Optional args:

- `password`: default `123`.
- `conversation_id`: optional metadata filter.
- `conversation_type`: `auto`, `direct`, `group`, or `system`; default `auto`.
- `query`: optional metadata filter. Body columns are searched only when `include_body=true`.
- `since`: optional timestamp lower bound using the DB timestamp column representation.
- `cursor`: unsupported initially; any non-empty value is rejected.
- `limit`: bounded to `1..50`; default `20`.
- `include_body`: default `false`.
- `include_attachment_metadata`: default `false`; returns filename/size metadata only, never path values or download refs.

Returned data adds:

- `read_only=true`
- `message_body_values_returned`: equals `include_body`.
- `raw_rows_returned=false`
- `file_paths_returned=false`
- `source_tables[]`
- `messages[]` entries with normalized fields:
  - `message_id` / `id`
  - `conversation_id`
  - `conversation_type`
  - `sender_id`
  - `sender_name`
  - `receiver_id`
  - `text` / `content_text` (empty when `include_body=false`)
  - `content_type`
  - `timestamp` / `created_at`
  - `subject`
  - `read`
  - `source=local_readonly`
  - `raw_ref=msglib:<table>`
  - `attachments[]` with `file_id`, `file_name`, `size_bytes`, and empty `download_ref`
- `next_cursor=null`

Initial allowlisted message sources:

- Direct: `tblPersonMsg`.
- Group: `tblMsgGroupPersonMsg`.
- System: `TD_SystemMessageRecord`.
- Attachment metadata: `TD_ReceiveFileRecord`, with `FilePath`/path-like values intentionally excluded.

## Security and scope rules

- The sidecar must open DB files with read-only connection settings.
- `db_path` must point to a file named `MsgLib.db`.
- The schema/display-source operations return schema, columns, counts, and display-source availability only.
- `display_entities` may return bounded contact/group `jid` and `display_name` metadata only.
- `message_sources` may return message-source table names, required/present column names, roles, availability flags, and row counts only.
- `list_messages` may return bounded normalized message metadata. It returns `text`/`content_text` only when `include_body=true`; the standard verification path uses `include_body=false`.
- It does not return file path values, attachment contents, raw row sets, sends, downloads, hooks, injection, or DB writes.
- It does not implement send, file download, mark-read, login, hooks, injection, or DB writes.
- The Go MCP layer remains the coordinator; this process is a bounded local reader.

## Current implementation

Committed C27 implementation:

- Source: `native/MsgLibReadSidecar/`.
- Build script: `scripts/build-msglib-sidecar.ps1`.
- Verification script: `scripts/verify-msglib-sidecar.ps1`.
- Default verification builds an x86 executable and checks `self_check`.
- Evidence-backed verification with C26 paths checked provider load/read-only DB open and returned 8 display-source candidates.

## Go client wrapper

Committed C28 implementation:

- Source: `internal/msglib/`.
- `ConfigFromEnv` reads `ISPHERE_MSGLIB_SIDECAR_EXE`, `ISPHERE_MSGLIB_SQLITE_DLL`, `ISPHERE_MSGLIB_DB`, and optional `ISPHERE_MSGLIB_PASSWORD`.
- `NewClient` creates a process-backed client for protocol `isphere.msglib.v1`.
- `SelfCheck` calls `self_check` and decodes sidecar identity, protocol, bitness, and read-only/no-mutation flags.
- `DisplaySources` calls `display_sources` and decodes display-source availability metadata.
- The client uses stdin/stdout JSON, request ids, `context.Context`, per-call timeout, stderr capture, and typed `SidecarError` values.
- Unit tests use a fake sidecar process; normal tests do not require real `System.Data.SQLite.dll` or copied `MsgLib.db`.
- C28 does not register a new MCP tool and does not return message bodies, file paths, raw rows, contact row values, or group row values.

Committed C29 implementation:

- Sidecar op: `display_entities`.
- Go wrapper: `DisplayEntities(ctx, DisplayEntitiesOptions)`.
- Verification script calls `display_entities` only when copied DB env paths are supplied, and prints only sanitized `entity_count` plus `source_tables` summaries.
- Evidence-backed C29 verification against the copied DB returned contact/group entity counts and source-table names without printing entity values.
- C31 adds optional `scripts/verify-msglib-mcp-enrichment.ps1` to prove MCP-level contact/group enrichment through the real sidecar while printing only counts and `msglib:<source_table>` refs. C33 extends the same optional script to create a synthetic encrypted PacketReader fixture from internally selected MsgLib contact/group metadata and verify receive-message `sender_name` plus `conversation.display_name` enrichment; the printed result remains limited to counts, booleans, and source refs.

Committed C36 implementation:

- Sidecar op: `message_sources`.
- Go wrapper: `MessageSources(ctx)`.
- Verification script calls `message_sources` only when copied DB env paths are supplied, and prints only sanitized `message_source_count` plus message-source summaries containing source/table/role/availability/row-count metadata.
- Evidence-backed C36 verification against the copied DB returned six message-source summaries without printing message body values, file path values, raw rows, or copied DB contents.

Committed C38 implementation:

- Sidecar op: `list_messages`.
- Go wrapper: `ListMessages(ctx, ListMessagesOptions)`.
- The op reads only allowlisted direct/group/system message tables and optional received-file metadata from a copied `MsgLib.db`, clamps `limit` to `1..50`, rejects non-empty cursor, and never returns raw rows or file path values.
- `scripts/verify-msglib-sidecar.ps1` calls `list_messages` only when copied DB env paths are supplied, with `include_body=false`, and prints only `message_list_count`, `message_list_sources`, safety booleans, and omission booleans.
- Evidence-backed C38 smoke returned normalized message count/source-table evidence without printing message text, body values, file paths, download refs, raw rows, sends, downloads, hooks, injection, or DB writes.

## Verification

Default verification builds and checks `self_check` only:

```powershell
powershell -NoProfile -ExecutionPolicy Bypass -File scripts\verify-msglib-sidecar.ps1
```

Evidence-backed provider verification is opt-in through environment variables and should use copied DB files only. The script also verifies `display_sources` and sanitized `display_entities` summaries when these variables are present:

```powershell
$env:ISPHERE_MSGLIB_SQLITE_DLL = "<path-to-System.Data.SQLite.dll>"
$env:ISPHERE_MSGLIB_DB = "<path-to-copied-MsgLib.db>"
powershell -NoProfile -ExecutionPolicy Bypass -File scripts\verify-msglib-sidecar.ps1
```

Optional MCP enrichment smoke, including receive-message display enrichment, is also opt-in through the same copied DB environment variables:

```powershell
$env:ISPHERE_MSGLIB_SQLITE_DLL = "<path-to-System.Data.SQLite.dll>"
$env:ISPHERE_MSGLIB_DB = "<path-to-copied-MsgLib.db>"
powershell -NoProfile -ExecutionPolicy Bypass -File scripts\verify-msglib-mcp-enrichment.ps1
```

Expected printed evidence is sanitized: contact/group counts, `msglib:<source_table>` refs, `message_source_count`, message-source table/role/row-count summaries, `receive_display_smoke=true`, populated-field booleans, and no entity values, message bodies, file path values, or raw rows.

C38 provider verification additionally prints `message_list_count`, `message_list_sources`, `message_list_body_values_returned=false`, `message_list_raw_rows_returned=false`, `message_list_file_paths_returned=false`, `message_list_content_values_omitted=true`, and `message_list_download_refs_omitted=true`.