Merge PR #747 from MMexicann: MCP: validate reply IDs and bounded response frames (#718)

docs/control-protocol.md

@@ -3,6 +3,12 @@
 Start the app with `--control <port>`. The server listens on `127.0.0.1` only and speaks JSON
 lines: one request object per line, one reply per line.
 
+The connected MCP client requires the reply's numeric `id` to match its request, `ok` to be a
+boolean, and exactly one of `result` (success) or a string `error` (failure). It caps each reply at
+16 MiB including its terminating newline, accepts CRLF, and rejects EOF inside a frame. Invalid
+replies invalidate the connection and leave the command's outcome unknown; the client does not
+replay it. Unsolicited bytes already buffered between calls force a reconnect before sending.
+
 The server bounds what a client can hold: 16 connections at once (more get `{"ok":false,"error":"busy: …"}`
 and are closed), 16 MiB per request line (longer closes the connection), 64 queued requests (more are
 answered `busy`), 10 minutes idle and 30 seconds per blocked reply write before the socket is closed, and

docs/gaps.md

@@ -1,6 +1,6 @@
 # Where DeckCraft falls short of PowerPoint
 
-> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** major (community PR wave 2026-10-14: soak tests, PPTX corpus, comment threads (#70), embedded fonts, SmartArt Text Pane, Animation Pane timeline, Hunspell spelling, thesaurus, AutoCorrect, 14 new dialogs, pen pressure and trackpad gestures; duplicated entries and headers folded; previous: minor, 3-D bevel, camera and face lighting rendered) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** trivial (connected MCP reply validation, #718; existing gaps and estimates unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 Every known shortfall, one entry each, ranked by how much it stops someone who presents with
 PowerPoint from switching. This is the work list: pick from the top. Numbers are summarized in
@@ -355,6 +355,7 @@ Detail in [localization-parity.md](localization-parity.md).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-14 | trivial | Fixed #718: remote MCP no longer accepts unrelated or buffered stale success; loopback regressions cover invalid envelopes, incomplete and oversized frames |
 | 2026-10-14 | minor | Community PR wave folded: one entry each for the soak tests (engine and UI), the PPTX corpus (seven owned corpus files), edit points / text warp / 3-D, proofing (Hunspell spelling, thesaurus, AutoCorrect), the smaller missing rows, dialogs (41 vs ~60; Print and Insert Object left) and pen/trackpad input; ranked rows 3, 4 and 10 de-duplicated (comment threads #70 and the pane timeline are done); the fixed command-palette entry (#79) removed |
 | 2026-10-13 | minor | EMF/WMF rectangle clip regions (`INTERSECTCLIPRECT`, `EXCLUDECLIPRECT`, `EXTSELECTCLIPRGN`) limit later drawing. EMF+ records remain |
 | 2026-10-13 | minor | Embedded fonts are read, written and drawn (TrueType, OpenType, Embedded OpenType). The gap is now MicroType Express subsets, which are kept but not drawn |

docs/mcp.md

@@ -5,6 +5,18 @@ headless engine (no window); with `--connect PORT` it drives a running DeckCraft
 `--control PORT`, so an agent and a person can work on the same deck. `--sample` opens the sample
 deck.
 
+Connected mode accepts only newline-terminated replies of at most 16 MiB (including the newline),
+with the current request's numeric `id`, a boolean `ok`, and either `result` on success or a string
+`error` on failure. CRLF is accepted. Invalid replies close the connection and report that the
+command may or may not have run; they never cause a replay. Check the document before retrying a
+mutation. Before sending another request, unsolicited bytes in the reader's buffer or on the
+socket cause a fresh connection to be opened. Large image replies must fit this budget; render
+to a file or use a smaller scale when necessary.
+
+Regression coverage for #718 lives in `crates/mcp/src/backend.rs`: synthetic loopback peers test
+reply correlation, envelopes, framing, the size cap and buffered unsolicited bytes, alongside the
+lost-reply and reconnect tests.
+
 ```json
 {
   "mcpServers": {

docs/parity-checklist.md

@@ -228,7 +228,7 @@ Open P0 items: Contextual tabs (Shape Format, Picture Format, Table Design/Layou
 | Undo & clipboard | Unlimited undo/redo | P0 | D |
 | Undo & clipboard | Cut, copy, paste shapes and slides | P0 | D |
 | Undo & clipboard | Paste special (keep formatting, picture, text only) | P1 | D |
-| Automation (✱) | Every command scriptable (CLI, control channel, MCP) | P0 | D |
+| Automation (✱) | Every command scriptable (CLI, control channel, MCP; remote reply IDs, envelopes and framing validated, #718) | P0 | D |
 | Automation (✱) | Headless rendering and conversion | P0 | D |
 | Platforms (✱) | macOS, Windows, Linux builds | P0 | P |
 | Platforms (✱) | Web (WASM) build | P1 | D |

docs/roadmap.md

@@ -1,6 +1,6 @@
 # DeckCraft roadmap: milestones and what's next
 
-> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** major (community PR wave 2026-10-14: PPTX corpus, presenter and show controls, review navigation, starter decks, Grid Options and New Window, WordArt gallery and handles, pen pressure; beta items 9 and 10 narrowed; duplicated rows and headers folded; previous: minor, core-workflow alpha gate added) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** trivial (M13 connected MCP reply validation, #718; beta priorities unchanged) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 Forward-looking: where DeckCraft is going and in what order. The one-page summary is
 [ROADMAP.md](../ROADMAP.md); every shortfall is in [gaps.md](gaps.md); numbers are in
@@ -115,6 +115,7 @@ plan above.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-14 | trivial | M13 reliability: remote MCP validates IDs and envelopes, caps replies and rejects incomplete frames; #718 |
 | 2026-10-14 | minor | Community PR wave folded: one Review gate row, one Current focus item 2, one beta row each for items 9 and 10 (timeline and timer controls are in), one after-beta paragraph, one M9 and M10 row, one corpus row in the 2026-10-07 history |
 | 2026-10-13 | trivial | Beta item 3: embedded fonts are in, except MicroType Express subsets |
 | 2026-10-13 | minor | M9: the WordArt Transform gallery applies a text warp; adjust handles stay open |