flynn/docs/plans/2026-02-11-model-persistence-per-session.md

Plan: Model Persistence with Per-Session Overrides

Summary

This plan fixes model tier persistence so it works correctly across TUI, WebChat, and Telegram channels, and adds per-session model overrides that survive daemon restarts. Currently the model tier is a single global preference stored in preferences.json and propagated via ModelRouter.setTier(). This creates three problems:

1. Global coupling: Switching models in TUI changes WebChat sessions too (via SessionBridge.onTierChanged)
2. No per-session persistence: Channel adapter sessions (Telegram, Discord, etc.) can't have independent model overrides
3. WebChat uses raw NativeAgent: The SessionBridge creates NativeAgent instances directly instead of AgentOrchestrator, losing delegation, compaction, memory, and proper usage tracking

The solution introduces a session_config SQLite table for per-session key-value settings, wires it through SessionManager, and changes the model resolution chain to: session override → agent config → global default.

Context

• Request: Fix model persistence across all channels with per-session overrides
• Codebase: Flynn multi-channel AI assistant daemon with TUI, WebChat (gateway), Telegram, Discord, Slack adapters
• Constraints: Must be backwards-compatible; existing preferences.json global default must still work; no breaking changes to gateway protocol

Current Architecture (Problems)

Problem 1: Global Model Tier Coupling

In src/daemon/index.ts (lines 104-110):

modelRouter.setOnTierChange((tier) => savePreference(dataDir, 'modelTier', tier));

In src/gateway/session-bridge.ts (lines 38-51):

// SessionBridge subscribes to tier changes and updates ALL WebChat agents
router.addOnTierChange((tier: ModelTier) => this.onTierChanged(tier));
// ...
private onTierChanged(tier: ModelTier): void {
  this.currentTier = tier;
  for (const agent of this.agents.values()) {
    agent.setModelTier(tier);
  }
}

This means /model fast in TUI immediately switches all WebChat sessions to fast too.

Problem 2: No Per-Session Config Persistence

The SessionStore only stores messages. There's no mechanism to persist per-session settings like model tier overrides. When the daemon restarts, all sessions lose their model tier.

Problem 3: WebChat Uses NativeAgent Instead of AgentOrchestrator

SessionBridge.getOrCreateAgent() (line 186) creates raw NativeAgent instances:

agent = new NativeAgent({
  modelClient: this.config.modelClient,
  systemPrompt: this.config.systemPrompt,
  session,
  toolRegistry: this.config.toolRegistry,
  toolExecutor: this.config.toolExecutor,
});

This means WebChat sessions lack: delegation to sub-agents, automatic compaction, memory injection, proper cost tracking, and tool policy context.

Problem 4: Telegram Has No /model Command in Channel Adapter

The TelegramAdapter (channel-based) has /reset and /start commands but no /model command. The old src/frontends/telegram/bot.ts has /local, /cloud, /model commands but those operate on a shared NativeAgent, not per-session.

Design Decisions

Decision 1: SQLite session_config Table for Per-Session Settings

• Choice: Add a session_config table with (session_id, key, value) columns
• Rationale: Sessions already persist in SQLite; config is a natural extension. Key-value is flexible enough for future settings (not just model tier).
• Alternatives considered: JSON file per session (too many files), adding columns to messages table (wrong abstraction), in-memory only (lost on restart)

Decision 2: Three-Level Model Resolution Chain

• Choice: Session override → Agent config → Global default
• Rationale: Allows users to override per-session while falling back to agent routing config and then global preferences. This matches the existing pattern in routing.ts line 63.
• Alternatives considered: Two-level (session → global) loses agent config routing; single global (current) is too coarse

Decision 3: WebChat Upgrade to AgentOrchestrator

• Choice: Replace NativeAgent with AgentOrchestrator in SessionBridge
• Rationale: WebChat sessions should have feature parity with channel adapter sessions (delegation, compaction, memory). This is a prerequisite for per-session model persistence to work properly.
• Alternatives considered: Keep NativeAgent but add a tier override field (doesn't fix delegation/compaction gap)

Decision 4: Model Commands via Channel Message Metadata

• Choice: Handle /model in Telegram adapter by sending metadata through the message handler, and in WebChat via the agent.send handler
• Rationale: Consistent with existing /reset pattern — commands are dispatched as InboundMessage with metadata.isCommand = true
• Alternatives considered: Separate RPC endpoint for model switching (adds protocol complexity)

Implementation Steps

Step 1: Database Schema — session_config Table

Files: src/session/store.ts

Changes:

• Add session_config table creation in init() method
• Add CRUD methods for session config

Details:

In init() (line 22), add to the this.db.exec() call:

CREATE TABLE IF NOT EXISTS session_config (
  session_id TEXT NOT NULL,
  key TEXT NOT NULL,
  value TEXT NOT NULL,
  PRIMARY KEY (session_id, key)
);

Add these new methods to SessionStore:

/** Get a single config value for a session. */
getSessionConfig(sessionId: string, key: string): string | undefined {
  const stmt = this.db.prepare(
    'SELECT value FROM session_config WHERE session_id = ? AND key = ?',
  );
  const row = stmt.get(sessionId, key) as { value: string } | undefined;
  return row?.value;
}

/** Get all config values for a session. */
getAllSessionConfig(sessionId: string): Record<string, string> {
  const stmt = this.db.prepare(
    'SELECT key, value FROM session_config WHERE session_id = ?',
  );
  const rows = stmt.all(sessionId) as Array<{ key: string; value: string }>;
  const result: Record<string, string> = {};
  for (const row of rows) {
    result[row.key] = row.value;
  }
  return result;
}

/** Set a config value for a session. Upserts (INSERT OR REPLACE). */
setSessionConfig(sessionId: string, key: string, value: string): void {
  this.db.prepare(
    'INSERT OR REPLACE INTO session_config (session_id, key, value) VALUES (?, ?, ?)',
  ).run(sessionId, key, value);
}

/** Delete a config value for a session. */
deleteSessionConfig(sessionId: string, key: string): void {
  this.db.prepare(
    'DELETE FROM session_config WHERE session_id = ? AND key = ?',
  ).run(sessionId, key);
}

/** Delete all config for a session (used when session is cleared/pruned). */
clearSessionConfig(sessionId: string): void {
  this.db.prepare(
    'DELETE FROM session_config WHERE session_id = ?',
  ).run(sessionId);
}

Also update clearSession() (line 80) to also clear config:

clearSession(sessionId: string): void {
  const transaction = this.db.transaction(() => {
    this.db.prepare('DELETE FROM messages WHERE session_id = ?').run(sessionId);
    this.db.prepare('DELETE FROM session_config WHERE session_id = ?').run(sessionId);
  });
  transaction();
}

And update pruneStale() (line 92) to also clean up config for pruned sessions:

pruneStale(beforeTimestamp: number): string[] {
  // ... existing stale detection ...
  const deleteMessages = this.db.prepare('DELETE FROM messages WHERE session_id = ?');
  const deleteConfig = this.db.prepare('DELETE FROM session_config WHERE session_id = ?');
  const transaction = this.db.transaction(() => {
    for (const { session_id } of stale) {
      deleteMessages.run(session_id);
      deleteConfig.run(session_id);
    }
  });
  transaction();
  return stale.map(r => r.session_id);
}

---

Step 2: SessionManager Config Methods

Files: src/session/manager.ts

Changes:

• Add getSessionConfig(), setSessionConfig(), deleteSessionConfig() methods to SessionManager
• Add config methods to ManagedSession
• Update Session interface

Details:

Update the Session interface (line 5):

export interface Session {
  id: string;
  addMessage(message: Message): void;
  getHistory(): Message[];
  clear(): void;
  replaceHistory(messages: Message[]): void;
  getConfig(key: string): string | undefined;
  setConfig(key: string, value: string): void;
  deleteConfig(key: string): void;
}

Add methods to ManagedSession (after line 66):

getConfig(key: string): string | undefined {
  return this.store.getSessionConfig(this.id, key);
}

setConfig(key: string, value: string): void {
  this.store.setSessionConfig(this.id, key, value);
}

deleteConfig(key: string): void {
  this.store.deleteSessionConfig(this.id, key);
}

Add convenience methods to SessionManager (after line 131):

/** Get a session config value. */
getSessionConfig(frontend: string, userId: string, key: string): string | undefined {
  const session = this.getSession(frontend, userId);
  return session.getConfig(key);
}

/** Set a session config value. */
setSessionConfig(frontend: string, userId: string, key: string, value: string): void {
  const session = this.getSession(frontend, userId);
  session.setConfig(key, value);
}

/** Delete a session config value. */
deleteSessionConfig(frontend: string, userId: string, key: string): void {
  const session = this.getSession(frontend, userId);
  session.deleteConfig(key);
}

Update src/session/index.ts to export the new Session interface properly (already done, Session is re-exported).

---

Step 3: Model Resolution in routing.ts

Files: src/daemon/routing.ts

Changes:

• Read per-session model tier override when creating/reusing an agent
• Persist model tier to session config when it changes
• Add /model command handling in the message handler

Details:

In getOrCreateAgent() (line 43), after getting the session, read the session config:

const session = deps.sessionManager.getSession(channel, senderId);

// Read per-session model tier override (persisted in SQLite)
const sessionTierOverride = session.getConfig('modelTier') as ModelTier | undefined;

// Resolution chain: metadata (cron) → session override → agent config → global default
const effectiveTier = tierFromMetadata
  ?? sessionTierOverride
  ?? agentConfig?.modelTier
  ?? deps.config.agents.primary_tier
  ?? 'default';

This replaces line 63 which currently doesn't check session config.

Add a /model command handler in the handler function (after the existing /usage handler, around line 212):

if (msg.metadata.command === 'model') {
  const modelArg = msg.metadata.commandArgs as string | undefined;
  const { orchestrator: agent } = getOrCreateAgent(msg.channel, msg.senderId, msg.metadata);
  const session = deps.sessionManager.getSession(msg.channel, msg.senderId);

  if (!modelArg) {
    // Show current model tier
    const currentTier = agent.getModelTier();
    const sessionOverride = session.getConfig('modelTier');
    const available = deps.modelRouter.getAvailableTiers();
    const labels = deps.modelRouter.getAllLabels();
    const lines = [`Active tier: ${currentTier}${sessionOverride ? ' (session override)' : ''}`];
    for (const tier of available) {
      const label = labels[tier] ?? 'unknown';
      const marker = tier === currentTier ? ' ←' : '';
      lines.push(`  ${tier}: ${label}${marker}`);
    }
    await reply({ text: lines.join('\n'), replyTo: msg.id });
    return;
  }

  // Resolve alias and switch tier
  const tier = resolveModelAlias(modelArg);
  if (!deps.modelRouter.getAvailableTiers().includes(tier)) {
    await reply({ text: `Model tier not available: ${modelArg}`, replyTo: msg.id });
    return;
  }

  // Persist to session config
  session.setConfig('modelTier', tier);

  // Update the orchestrator's agent tier
  agent.setModelTier(tier);

  const label = deps.modelRouter.getLabel(tier);
  await reply({ text: `Switched to model: ${tier} (${label})`, replyTo: msg.id });
  return;
}

Also add the resolveModelAlias import at the top:

import { resolveModelAlias } from '../frontends/tui/commands.js';

And update the audio tier resolution section (lines 217-228) to also check session override:

let effectiveTier: string = deps.config.agents.primary_tier ?? 'default';
const session = deps.sessionManager.getSession(msg.channel, msg.senderId);
const sessionTierOverride = session.getConfig('modelTier');

if (msg.metadata?.modelTier) {
  effectiveTier = msg.metadata.modelTier as string;
} else if (sessionTierOverride) {
  effectiveTier = sessionTierOverride;
} else if (deps.agentRouter && deps.agentConfigRegistry) {
  // ... existing agent config lookup ...
}

Important: The agent cache in routing.ts keys on session ID + agent config name. When the model tier changes per-session, we need to invalidate the cached agent or update it in place. Since AgentOrchestrator.setModelTier() already exists and updates the underlying NativeAgent, updating in place is sufficient — no cache invalidation needed.

However, note that tierFromMetadata (for cron jobs) currently affects the cache key (line 55). Per-session overrides should NOT affect the cache key because the agent is already created and we update it in place.

---

Step 4: Reset Command — Clear Session Overrides

Files: src/daemon/routing.ts

Changes:

• When /reset is handled, also clear session config

Details:

In the reset handler (line 167):

if (msg.metadata.command === 'reset') {
  agent.reset();
  // Clear per-session config overrides
  const session = deps.sessionManager.getSession(msg.channel, msg.senderId);
  session.deleteConfig('modelTier');
  return;
}

---

Step 5: WebChat SessionBridge — Upgrade to AgentOrchestrator

Files: src/gateway/session-bridge.ts

Changes:

• Replace NativeAgent with AgentOrchestrator
• Accept additional config for orchestrator creation (delegation, compaction, memory, etc.)
• Remove global tier sync (each session manages its own tier)
• Load per-session tier from session config on creation

Details:

Update the interface and imports:

import { AgentOrchestrator, type DelegationConfig } from '../backends/native/orchestrator.js';
import type { MemoryStore } from '../memory/store.js';
import type { Config } from '../config/index.js';
// Remove NativeAgent import (no longer directly used)

Update SessionBridgeConfig:

export interface SessionBridgeConfig {
  sessionManager: SessionManager;
  modelClient: ModelClient | ModelRouter;
  systemPrompt: string;
  toolRegistry: ToolRegistry;
  toolExecutor: ToolExecutor;
  config?: Config;
  memoryStore?: MemoryStore;
}

Replace NativeAgent references with AgentOrchestrator:

interface ClientEntry {
  connectionId: string;
  sessionId: string;
  agent: AgentOrchestrator;
  busy: boolean;
}

export class SessionBridge {
  private clients: Map<string, ClientEntry> = new Map();
  private agents: Map<string, AgentOrchestrator> = new Map();
  // ...

Remove the onTierChanged method and the addOnTierChange subscription in the constructor. WebChat sessions should NOT follow TUI tier changes — they manage their own tier via session config.

Update getOrCreateAgent():

private getOrCreateAgent(sessionId: string): AgentOrchestrator {
  let agent = this.agents.get(sessionId);
  if (!agent) {
    const session = this.config.sessionManager.getSession('ws', sessionId);
    const config = this.config.config;

    // Read per-session tier override from session config
    const sessionTier = session.getConfig?.('modelTier') as ModelTier | undefined;
    const primaryTier = sessionTier ?? config?.agents.primary_tier ?? 'default';

    const delegationConfig: DelegationConfig = {
      compaction: config?.agents.delegation.compaction ?? 'fast',
      memory_extraction: config?.agents.delegation.memory_extraction ?? 'fast',
      classification: config?.agents.delegation.classification ?? 'fast',
      tool_summarisation: config?.agents.delegation.tool_summarisation ?? 'fast',
      complex_reasoning: config?.agents.delegation.complex_reasoning ?? 'complex',
    };

    agent = new AgentOrchestrator({
      modelRouter: this.config.modelClient as ModelRouter,
      systemPrompt: this.config.systemPrompt,
      session,
      toolRegistry: this.config.toolRegistry,
      toolExecutor: this.config.toolExecutor,
      primaryTier,
      delegation: delegationConfig,
      maxDelegationDepth: config?.agents.max_delegation_depth ?? 3,
      maxIterations: config?.agents.max_iterations,
      compaction: config?.compaction.enabled ? {
        thresholdPct: config.compaction.threshold_pct,
        keepTurns: config.compaction.keep_turns,
        summaryMaxTokens: config.compaction.summary_max_tokens,
      } : undefined,
      modelName: config?.models.default.model,
      contextWindow: config?.models.default.context_window,
      memoryStore: this.config.memoryStore,
    });

    this.agents.set(sessionId, agent);
  }
  return agent;
}

Update the getAgent() method signature and callers — they now get AgentOrchestrator which has the same process(), reset(), setModelTier(), setOnToolUse() methods.

Update getAllUsage() to use AgentOrchestrator.getUsage() which returns the richer UsageReport format:

getAllUsage(): Array<{
  sessionId: string;
  primary: { inputTokens: number; outputTokens: number; calls: number };
  delegation: Record<string, { inputTokens: number; outputTokens: number; calls: number }>;
  total: { inputTokens: number; outputTokens: number; calls: number; estimatedCost: number };
}> {
  const results = [];
  const seen = new Set<string>();
  for (const client of this.clients.values()) {
    if (seen.has(client.sessionId)) continue;
    seen.add(client.sessionId);
    const usage = client.agent.getUsage();
    results.push({ sessionId: client.sessionId, ...usage });
  }
  return results;
}

---

Step 6: WebChat Agent Handler — Add /model Command

Files: src/gateway/handlers/agent.ts

Changes:

• Add /model command handling in agent.send
• Persist model tier change to session config

Details:

In the command handling section (around line 47), add model command support:

if (params.metadata?.isCommand) {
  try {
    if (params.metadata.command === 'reset') {
      agent.reset();
      // Clear session config
      const sessionId = deps.sessionBridge.getSessionId(connectionId);
      if (sessionId) {
        const session = deps.sessionManager.getSession('ws', sessionId);
        session.deleteConfig('modelTier');
      }
      send(makeEvent(request.id, 'done', { content: 'Session reset.' }));
      return;
    }

    if (params.metadata.command === 'model') {
      const modelArg = params.metadata.commandArgs as string | undefined;
      const sessionId = deps.sessionBridge.getSessionId(connectionId);

      if (!modelArg) {
        // Show current tier info
        const currentTier = agent.getModelTier();
        send(makeEvent(request.id, 'done', {
          content: `Current model tier: ${currentTier}`,
        }));
        return;
      }

      // Validate tier
      const validTiers = ['fast', 'default', 'complex', 'local'];
      const tier = modelArg as ModelTier;
      if (!validTiers.includes(tier)) {
        send(makeEvent(request.id, 'done', {
          content: `Invalid tier: ${modelArg}. Available: ${validTiers.join(', ')}`,
        }));
        return;
      }

      // Update agent tier
      agent.setModelTier(tier);

      // Persist to session config
      if (sessionId) {
        const session = deps.sessionManager.getSession('ws', sessionId);
        session.setConfig('modelTier', tier);
      }

      send(makeEvent(request.id, 'done', {
        content: `Switched to model tier: ${tier}`,
      }));
      return;
    }
  } finally {
    deps.sessionBridge.setBusy(connectionId, false);
    deps.metrics?.endRequest(requestId);
  }
}

This requires updating AgentHandlerDeps to include sessionManager:

export interface AgentHandlerDeps {
  sessionBridge: SessionBridge;
  laneQueue: LaneQueue;
  metrics?: MetricsCollector;
  sessionManager?: SessionManager;
}

And updating the handler registration in server.ts (line 126):

const agentHandlers = createAgentHandlers({
  sessionBridge: this.sessionBridge,
  laneQueue: this.laneQueue,
  metrics: this.metrics,
  sessionManager: this.config.sessionManager,
});

---

Step 7: Telegram Adapter — Add /model Command

Files: src/channels/telegram/adapter.ts

Changes:

• Add /model command handler that dispatches through the message handler

Details:

After the /reset command handler (line 150), add:

this.bot.command('model', async (ctx) => {
  if (!this.messageHandler) return;

  const args = ctx.message?.text?.replace(/^\/model\s*/, '').trim() ?? '';

  this.messageHandler({
    id: String(ctx.message?.message_id ?? Date.now()),
    channel: 'telegram',
    senderId: String(ctx.chat.id),
    senderName: ctx.from?.first_name,
    text: `/model ${args}`.trim(),
    timestamp: Date.now(),
    metadata: {
      isCommand: true,
      command: 'model',
      commandArgs: args || undefined,
    },
  });
});

Also add /local and /cloud as convenience aliases:

this.bot.command('local', async (ctx) => {
  if (!this.messageHandler) return;
  this.messageHandler({
    id: String(ctx.message?.message_id ?? Date.now()),
    channel: 'telegram',
    senderId: String(ctx.chat.id),
    senderName: ctx.from?.first_name,
    text: '/model local',
    timestamp: Date.now(),
    metadata: { isCommand: true, command: 'model', commandArgs: 'local' },
  });
});

this.bot.command('cloud', async (ctx) => {
  if (!this.messageHandler) return;
  this.messageHandler({
    id: String(ctx.message?.message_id ?? Date.now()),
    channel: 'telegram',
    senderId: String(ctx.chat.id),
    senderName: ctx.from?.first_name,
    text: '/model default',
    timestamp: Date.now(),
    metadata: { isCommand: true, command: 'model', commandArgs: 'default' },
  });
});

---

Step 8: Update Daemon index.ts — Stop Global Tier Sync

Files: src/daemon/index.ts

Changes:

• Keep modelRouter.setOnTierChange for persisting the global default, but document that this is the GLOBAL default only
• Remove modelRouter.setOnTierChange from triggering session-level changes

Details:

The current code (lines 104-110) is fine for the GLOBAL default:

// Restore persisted global model tier default
if (prefs.modelTier) {
  modelRouter.setTier(prefs.modelTier as ModelTier);
}
// Persist global default when changed via TUI
modelRouter.setOnTierChange((tier) => savePreference(dataDir, 'modelTier', tier));

This is correct — TUI /model changes the global default. The SessionBridge no longer syncs to this (per Step 5), so WebChat sessions are unaffected. Channel adapter sessions use their own session config.

No changes needed here, but the SessionBridge change in Step 5 is what decouples WebChat from this global sync.

---

Step 9: Pass Additional Config to SessionBridge

Files: src/daemon/services.ts

Changes:

• Pass config and memoryStore to GatewayServer → SessionBridge

Details:

In createGateway() (line 126), the GatewayServer constructor already receives config. We need to also pass memoryStore if available.

Update GatewayDeps in services.ts:

export interface GatewayDeps {
  // ... existing fields ...
  memoryStore?: MemoryStore;
}

Update createGateway() to pass through:

const gateway = new GatewayServer({
  // ... existing config ...
  memoryStore: deps.memoryStore,
});

Update GatewayServerConfig in server.ts:

export interface GatewayServerConfig {
  // ... existing fields ...
  memoryStore?: MemoryStore;
}

And pass it to SessionBridge in GatewayServer constructor:

this.sessionBridge = new SessionBridge({
  sessionManager: config.sessionManager,
  modelClient: config.modelClient,
  systemPrompt: config.systemPrompt,
  toolRegistry: config.toolRegistry,
  toolExecutor: config.toolExecutor,
  config: config.config,
  memoryStore: config.memoryStore,
});

Update startDaemon() in daemon/index.ts to pass memoryStore:

const gateway = createGateway({
  config, sessionManager, modelRouter, systemPrompt, toolRegistry, toolExecutor,
  channelRegistry, pairingManager, lifecycle,
  getChannelAgents: () => channelAgents,
  memoryStore,  // ADD THIS
});

This requires extracting memoryStore from initMemory() result (it's already destructured on line 97).

---

Step 10: Update InboundMessage metadata Type

Files: src/channels/types.ts

Changes:

• Add commandArgs to the metadata type

Details:

Check if metadata is typed or Record<string, unknown>. If typed, add:

metadata?: {
  isCommand?: boolean;
  command?: string;
  commandArgs?: string;
  // ... other existing fields
  [key: string]: unknown;
};

If it's already Record<string, unknown>, no change needed (the field is dynamically accessed).

---

Step 11: Gateway agent.send Handler — Update for AgentOrchestrator

Files: src/gateway/handlers/agent.ts

Changes:

• Update agent.send to work with AgentOrchestrator instead of NativeAgent
• The API is the same: process(), reset(), setOnToolUse() all exist on both

Details:

Since AgentOrchestrator exposes the same public API as NativeAgent for the operations used in agent.ts, the handler code largely works unchanged. The getAgent() method on SessionBridge now returns AgentOrchestrator instead of NativeAgent.

Key method compatibility check:

• agent.process(message, attachments) ✅ (exists on both)
• agent.reset() ✅ (exists on both)
• agent.setOnToolUse(callback) ✅ (exists on both)
• agent.getUsage() — returns UsageReport on orchestrator vs {inputTokens, outputTokens, calls} on NativeAgent. The handler at line 96 just calls agent.process(), so no usage call here.
• agent.getModelTier() ✅ (exists on both)
• agent.setModelTier(tier) ✅ (exists on both)

The ToolUseEvent type is the same for both.

---

File Change Summary

File	Change Type	Description
src/session/store.ts	Modified	Add session_config table + CRUD methods
src/session/manager.ts	Modified	Add config methods to Session interface, ManagedSession, SessionManager
src/daemon/routing.ts	Modified	Session config resolution, /model command handler
src/gateway/session-bridge.ts	Modified	Replace NativeAgent with AgentOrchestrator, remove global tier sync
src/gateway/handlers/agent.ts	Modified	Add /model + /reset config clearing
src/gateway/server.ts	Modified	Pass sessionManager to agent handlers, memoryStore to SessionBridge
src/channels/telegram/adapter.ts	Modified	Add /model, /local, /cloud commands
src/daemon/services.ts	Modified	Pass memoryStore through to gateway
src/daemon/index.ts	Modified	Pass memoryStore to createGateway
src/channels/types.ts	Modified	Add commandArgs to metadata (if typed)

Testing

Unit Tests

• src/session/store.test.ts: Test session_config CRUD — set, get, getAll, delete, clearAll
• src/session/store.test.ts: Test clearSession() also clears config
• src/session/store.test.ts: Test pruneStale() also cleans config
• src/session/manager.test.ts: Test ManagedSession.getConfig/setConfig/deleteConfig
• src/daemon/routing.test.ts: Test model resolution chain (session → agent → global)
• src/daemon/routing.test.ts: Test /model command sets session config and updates agent tier
• src/daemon/routing.test.ts: Test /reset command clears session config
• src/gateway/session-bridge.test.ts: Test that tier changes in TUI do NOT affect WebChat sessions
• src/gateway/session-bridge.test.ts: Test that new agents load tier from session config
• src/gateway/handlers/handlers.test.ts: Test agent.send with model command

Integration Tests

• Start daemon, set model in TUI, verify WebChat session stays on its own model
• Set model via Telegram /model fast, restart daemon, verify Telegram session restores fast
• Set model via WebChat, reconnect WebSocket, verify session restores the tier
• /reset in any channel clears the model override back to global default

Manual Tests

• TUI: /model fast → check TUI uses fast, WebChat still uses default
• Telegram: /model local → check Telegram uses local, TUI unaffected
• WebChat: send { "method": "agent.send", "params": { "message": "/model fast", "metadata": { "isCommand": true, "command": "model", "commandArgs": "fast" } } } → verify tier switch
• Restart daemon → verify all channel sessions restore their per-session model tier

Risks and Mitigations

Risk	Mitigation
WebChat upgrade to AgentOrchestrator may change behavior	AgentOrchestrator wraps NativeAgent with identical public API; test thoroughly
Cached agents in routing.ts may get stale tier	setModelTier() updates in place, no cache invalidation needed
Session config table migration on existing DBs	CREATE TABLE IF NOT EXISTS is safe; no migration needed
Breaking changes to gateway protocol	No protocol changes — uses existing metadata.isCommand pattern
Memory/performance impact of per-session config	Minimal — single row per session per config key; read on agent creation only
Existing preferences.json global default conflicts with session override	Clear precedence chain: session → agent config → global. Documented above

Open Questions

1. Should /model in TUI also persist as a session override for the TUI session? Currently TUI /model changes the global ModelRouter tier. Should it additionally write to the TUI session config? Recommendation: No — TUI's model switch is intentionally global (affects preferences.json). Per-session overrides are for remote channels.

2. Should the WebChat dashboard show the per-session model tier? The dashboard currently shows token usage per session. Showing the active model tier per session would be a nice UX enhancement but is out of scope for this plan.

3. Should we expose a sessions.config.get / sessions.config.set gateway RPC method? This would allow the WebChat UI to query/set arbitrary session config. Recommendation: Defer to a follow-up — the /model command via agent.send is sufficient for now.