docs(05-03): complete discuss mode plan

- Create 05-03-SUMMARY.md with sequential discussion implementation details
- Update STATE.md: Plan 3 of 4, add decisions for sequential execution pattern
- Update ROADMAP.md: Phase 5 progress 3/4

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.planning/ROADMAP.md

@@ -76,5 +76,5 @@ Phases execute in numeric order: 1 → 2 → 3 → 4 → 5 → 6
 | 2. Bot Core | 2/2 | Complete | 2026-01-16 |
 | 3. Project CRUD | 3/3 | Complete | 2026-01-16 |
 | 4. Single Model Q&A | 2/2 | Complete | 2026-01-16 |
-| 5. Multi-Model Discussions | 2/4 | In progress | - |
+| 5. Multi-Model Discussions | 3/4 | In progress | - |
 | 6. Consensus & Export | 0/TBD | Not started | - |

.planning/STATE.md

@@ -10,18 +10,18 @@ See: .planning/PROJECT.md (updated 2026-01-16)
 ## Current Position
 
 Phase: 5 of 6 (Multi-Model Discussions)
-Plan: 2 of 4 in current phase
+Plan: 3 of 4 in current phase
 Status: In progress
-Last activity: 2026-01-16 — Completed 05-02-PLAN.md (open mode)
+Last activity: 2026-01-16 — Completed 05-03-PLAN.md (discuss mode)
 
-Progress: ████████░░ ~75%
+Progress: █████████░ ~80%
 
 ## Performance Metrics
 
 **Velocity:**
-- Total plans completed: 12
+- Total plans completed: 13
 - Average duration: 4 min
-- Total execution time: 0.75 hours
+- Total execution time: 0.82 hours
 
 **By Phase:**
 
@@ -31,10 +31,10 @@ Progress: ████████░░ ~75%
 | 02-bot-core | 2 | 4 min | 2 min |
 | 03-project-crud | 3 | 11 min | 4 min |
 | 04-single-model-qa | 2 | 10 min | 5 min |
-| 05-multi-model | 2 | 5 min | 2.5 min |
+| 05-multi-model | 3 | 10 min | 3 min |
 
 **Recent Trend:**
-- Last 5 plans: 04-01 (5 min), 04-02 (5 min), 05-01 (2 min), 05-02 (3 min)
+- Last 5 plans: 04-02 (5 min), 05-01 (2 min), 05-02 (3 min), 05-03 (5 min)
 - Trend: Fast
 
 ## Accumulated Context
@@ -66,6 +66,8 @@ Recent decisions affecting current work:
 - **04-02:** Typing indicator shown while waiting for AI response
 - **05-02:** asyncio.gather for parallel model queries with graceful per-model error handling
 - **05-02:** SYSTEM_PROMPT includes participant list and topic for roundtable context
+- **05-03:** Sequential model execution with for-loop so each model sees prior responses
+- **05-03:** Context stored in user_data["discussion_state"] for multi-command flows
 
 ### Deferred Issues
 
@@ -77,6 +79,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-01-16T19:37:57Z
+Last session: 2026-01-16T19:45:21Z
-Stopped at: Completed 05-02-PLAN.md (open mode)
+Stopped at: Completed 05-03-PLAN.md (discuss mode)
 Resume file: None

.planning/phases/05-multi-model-discussions/05-03-SUMMARY.md

@@ -0,0 +1,104 @@
+---
+phase: 05-multi-model-discussions
+plan: 03
+subsystem: api
+tags: [asyncio, telegram, ai-orchestration, sequential-rounds, context-building]
+
+# Dependency graph
+requires:
+  - phase: 05-multi-model-discussions/02
+    provides: Orchestrator with query_models_parallel, /open command
+  - phase: 04-single-model-qa/02
+    provides: AIClient.complete() and typing indicator pattern
+provides:
+  - build_context() for assembling discussion history
+  - run_discussion_round() for sequential model execution
+  - /discuss command for starting multi-round discussions
+  - /next command for round progression
+  - /stop command for early termination
+affects: [05-04-mentions, 06-consensus, 06-export]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns: [sequential model execution with context accumulation, user_data state for multi-command flows]
+
+key-files:
+  created: []
+  modified: [src/moai/core/orchestrator.py, src/moai/bot/handlers/discussion.py, src/moai/bot/handlers/__init__.py]
+
+key-decisions:
+  - "Sequential execution uses for-loop (not asyncio.gather) so each model sees prior responses"
+  - "Context stored in user_data['discussion_state'] for /next and /stop access"
+  - "All prior responses formatted as user messages with **Model:** prefix for context"
+
+patterns-established:
+  - "run_discussion_round returns dict[str, str] and creates Round+Messages"
+  - "Discussion state in user_data enables multi-command flows"
+
+issues-created: []
+
+# Metrics
+duration: 5min
+completed: 2026-01-16
+---
+
+# Phase 5 Plan 3: Discuss Mode Summary
+
+**Sequential multi-round discussion with /discuss, /next, /stop commands and full context building**
+
+## Performance
+
+- **Duration:** 5 min
+- **Started:** 2026-01-16T19:40:00Z
+- **Completed:** 2026-01-16T19:45:21Z
+- **Tasks:** 3
+- **Files modified:** 3
+
+## Accomplishments
+
+- Added build_context() to convert discussion history to OpenAI message format
+- Added run_discussion_round() for sequential model execution with context accumulation
+- Implemented /discuss [rounds] command with configurable round limit
+- Implemented /next for round progression and /stop for early termination
+- State stored in user_data for multi-command discussion flow
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Add context building and sequential round execution** - `9133d4e` (feat)
+2. **Task 2: Implement /discuss command handler** - `104eceb` (feat)
+3. **Task 3: Implement /next and /stop commands** - `3ae08e9` (feat)
+
+**Plan metadata:** (pending)
+
+## Files Created/Modified
+
+- `src/moai/core/orchestrator.py` - Added build_context() and run_discussion_round() functions
+- `src/moai/bot/handlers/discussion.py` - Added discuss_command, next_command, stop_command handlers
+- `src/moai/bot/handlers/__init__.py` - Registered /discuss, /next, /stop command handlers
+
+## Decisions Made
+
+- Sequential execution uses for-loop instead of asyncio.gather so each model sees responses from earlier models in the same round
+- Context messages use user role with **Model:** prefix for AI context
+- Discussion state stored in user_data["discussion_state"] for multi-command flow
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+
+None
+
+## Next Phase Readiness
+
+- M5 milestone (Discuss mode sequential) complete
+- Ready for 05-04-PLAN.md (@mention direct messages)
+- Discussion infrastructure ready for consensus generation in Phase 6
+
+---
+*Phase: 05-multi-model-discussions*
+*Completed: 2026-01-16*