feat(routing): per-channel MCP and built-in tool filtering

[nick-stebbings]

Summary

Add a JSON-configurable channel routing system that filters which MCP servers and built-in tools are offered to the LLM based on the incoming message channel.

Motivation

Multi-channel deployments (Slack + Telegram + web) need per-channel tool scoping. A research channel should only see research MCP tools, not production APIs. DMs should have broader access than shared channels.

How it works

Configuration at ~/.ironclaw/channel-routing.json:

{
  "groups": {
    "minimal": ["Archon"],
    "content": ["Archon", "Notion", "Kit"],
    "dev":     ["Archon", "Kiro", "Notion"]
  },
  "builtin_whitelist": {
    "content": ["memory_search", "create_job", "http_request"]
  },
  "channels": {
    "agentiffai-content": "content",
    "agentiffai-dev":     "dev"
  },
  "default_group": "minimal"
}

• groups: named sets of allowed MCP server prefixes
• builtin_whitelist: per-group allowlist of built-in tools (absent = all allowed)
• channels: channel name/ID → group mapping
• default_group: fallback for unmapped channels
• DM channels (slack-dm, telegram-dm, cli, web) bypass filtering entirely

MCP tools identified by server prefix (Notion_post_search → server Notion). Filtering applied per-iteration in the dispatcher so newly registered tools are always correctly scoped.

Test plan

• cargo test --lib passes (3162 tests, includes 10 routing-specific tests)
• cargo clippy --all --all-features clean
• cargo fmt --check clean
• Manual: message in mapped channel → tools filtered to group
• Manual: DM → all tools available (bypass)
• Manual: unmapped channel → default_group applied

🤖 Generated with Claude Code

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a robust and configurable system for managing tool access within multi-channel deployments. By allowing administrators to define which MCP servers and built-in tools are available to the LLM agent based on the originating channel, it significantly enhances the agent's contextual awareness and security. This prevents unintended tool usage across different communication contexts, such as restricting production APIs from research channels, and provides a flexible mechanism for tailoring the agent's capabilities to specific channel requirements.

Highlights

• JSON-configurable Channel Routing: Introduced a new system that allows configuring tool access based on the incoming message channel via a channel-routing.json file.
• Per-Channel Tool Filtering: Implemented filtering for both MCP (Multi-Channel Platform) server tools and built-in tools, allowing specific tools to be available only in designated channels or groups.
• Flexible Group Definitions: Enables defining named groups of allowed MCP server prefixes and whitelists for built-in tools, which channels can then be mapped to.
• Direct Message (DM) Bypass: Direct message channels (e.g., Slack DMs, Telegram DMs, CLI, web) are explicitly configured to bypass all tool filtering, granting full access to all available tools.
• Dynamic Filtering in Agent Loop: The tool filtering logic is applied dynamically at each iteration within the agent dispatcher, ensuring that newly registered tools are always correctly scoped according to the channel's configuration.

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[gemini-code-assist]

Code Review

This pull request introduces a channel routing system that filters MCP servers and built-in tools based on the incoming message channel, configurable via a JSON file. The changes include adding a new channel_routing.rs file, modifying agent_loop.rs and dispatcher.rs to incorporate the routing logic, and updating tests to account for the new functionality. The review focuses on correctness, maintainability, security, and performance, with suggestions for improved restrictiveness, efficiency, and consistent application of routing logic.

[nick-stebbings]

Addressed Gemini review feedback in 7114583:

• Restrictive default when group not found: Changed from allowing all tools to blocking all MCP tools (only built-in tools pass through). Misconfigured groups now fail safe.
• No panics in production code: Verified — all unwrap() calls are inside #[cfg(test)] test module.
• Test files updated: Added channel_routing: None to all test AgentDeps initializers that conflicted during rebase.

All checks pass (clippy, fmt, compilation).

[ilblackdragon]

Review: per-channel tool routing

The feature concept is sound — per-channel tool scoping is valuable for multi-channel deployments. However, the implementation has architectural and correctness issues that should be addressed before merge.

Architecture: config should live in the database, not a JSON file

The routing config is loaded from ~/.ironclaw/channel-routing.json once at startup. This means:

• No hot-reload: Changes require a full restart. Operators iterating on channel routing (the common case when setting this up) have a painful feedback loop.
• No web UI: Can't be configured through the settings page like other IronClaw settings. Every other user-facing configuration uses the database-backed settings system.
• No per-user scoping: The JSON file is global. The database settings system supports per-user settings naturally.

The right approach is to store this in the existing SettingsStore (like other config in src/settings.rs) and expose it through the web settings UI. This gets hot-reload for free — the settings system already handles that. The ChannelRoutingConfig struct and filtering logic are fine; it's just the persistence/loading layer that needs to change.

Correctness issues

1. MCP server name prefix matching is fragile: extract_mcp_server checks tool_name.starts_with("{server}_") by iterating all known servers. If one server name is a prefix of another (e.g., Kit and KitchenAI), Kit_ matches KitchenAI_recipe_search if checked first. Fix: sort by length descending, or pre-compute a lookup map keyed by longest-prefix match.

2. is_dm false-positives on channel names starting with "web": DM_PREFIXES includes "web", so a channel named web-team-standup would bypass all filtering via starts_with. Use exact matches or require a delimiter.

3. default_group is not validated at load time: If default_group: "typo" doesn't match any key in groups, every unmapped channel hits the restrictive fallback with a warning on every LLM iteration. Validate at load time.

Other

• The version bump (0.19.0 → 0.20.0) and CHANGELOG entries should be in a separate release PR — they reference unrelated PRs and make this harder to cherry-pick or revert.
• No integration test proving the dispatcher actually uses the filtered tools (unit tests for the config logic are good, but the wiring in dispatcher.rs is untested).

[nick-stebbings]

Addressed all review feedback in two commits (caab172, 6cb5d12):

Architecture: SettingsStore migration (6cb5d12)

• ChannelRoutingConfig now loads from SettingsStore database first, falls back to channel-routing.json file
• AgentDeps.channel_routing changed to Arc<RwLock<Option<...>>> — supports hot-reload via SIGHUP without restart
• apply_channel_routing is now async (acquires read lock)
• save_to_store() method added for web UI integration

Bug fixes (caab172)

1. MCP prefix matching — server names now sorted by length descending. KitchenAI_recipe_search correctly matches KitchenAI, not Kit. Test added.
2. is_dm false-positives — web is now exact-match only. web-team-standup no longer bypasses routing. slack-dm-* uses prefix-with-delimiter. Negative test cases added.
3. default_group validation — validate() checks at load time that default_group and all channel mappings reference existing groups. Invalid configs return None with error log. Two tests added.

Cleanup

• Added Serialize derive for DB persistence
• Added metadata_key field (optional, for compat with existing configs)
• Version bump / CHANGELOG not included in this PR (as requested)

Not yet addressed

• Integration test for dispatcher wiring — happy to add if the architecture changes are approved
• The extract_mcp_server now uses a static helper (extract_mcp_server_from) taking a sorted list, avoiding repeated group iteration

@ilblackdragon ready for re-review.

[nick-stebbings]

Addressed review feedback in latest push:

Architecture (ilblackdragon's main concern):

• Migrated config from channel-routing.json file to SettingsStore (database-backed)
• Added load_from_store() / save_to_store() on ChannelRoutingConfig
• No file fallback — SettingsStore is the single source of truth
• Changed AgentDeps.channel_routing to Arc<RwLock<Option<...>>> for hot-reload support
• apply_channel_routing is now async to support RwLock reads

Correctness fixes (from previous push, still included):

1. Restrictive default when group not found — blocks all MCP tools (fail-safe)
2. Load-time validation — default_group must exist in groups map
3. No panics in production code — all unwrap() calls inside #[cfg(test)]

Rebased onto latest staging (8f8cb7f7).

[zmanian]

Review -- REQUEST_CHANGES

The filtering logic and test coverage for the config module are solid. However, three blockers:

HIGH

1. is_dm() bypass uses wrong channel names -- Checks for "web", "slack-dm", "telegram-dm" but none match runtime names. Web chat uses "gateway", Slack uses "slack-relay" (DMs distinguished by metadata, not channel name), and no "telegram-dm" channel exists. The DM bypass never fires, so routing restrictions are applied to DMs (opposite of documented intent).

Fix: Check "gateway", "cli", "repl" as exact matches. For relay DMs, check metadata.event_type == "direct_message" (may need to pass metadata into filter_tool_defs).

2. Startup loads from "default" scope instead of config.owner_id -- ChannelRoutingConfig::load_from_store(db.as_ref(), "default") but SettingsStore is user-scoped. Any deployment where owner_id != "default" silently fails to load routing config, leaving all tools exposed.

Fix: Use config.owner_id.

3. No actual hot-reload -- AgentDeps.channel_routing is Arc<RwLock<...>> claiming hot-reload support, but the RwLock is only written at startup. SIGHUP handler doesn't refresh it. save_to_store() exists but is never called.

Fix: Either wire up SIGHUP refresh, or remove the RwLock / hot-reload claim until implemented.

Medium

4. Filtering only covers tool definitions, not execution -- Tools are hidden from the LLM but execute_tool doesn't re-verify channel permission. A hallucinated or injected tool name would still execute. Consider adding a secondary check in execute_tool_calls.

5. MCP server detection relies on tool_name.starts_with("{server}_") -- Fragile naming convention. A built-in tool named Archon_something would be misclassified. ToolDefinition should ideally carry provenance metadata.

[nick-stebbings]

Addressed all three points from @serrrfirat in 487cfc2, rebased onto latest staging (b6b3ffa1):

1. DM/web bypass aligned with runtime channel names (Medium)

• "web" → "gateway" (actual web chat WASM channel name)
• Removed "slack-dm" / "slack-dm-*" — Slack DMs arrive on the "slack" channel with metadata.channel starting with D (Slack convention for direct messages)
• Added Telegram DM detection via metadata.chat_type == "private"
• API change: is_dm() and filter_tool_defs() now accept metadata: &serde_json::Value to support relay-channel DM detection
• 8 new test assertions covering gateway, Slack DM vs channel, Telegram DM vs group

2. Owner scope fixed (High)

• Changed hardcoded "default" to config.owner_id at startup. Non-default deployments now correctly load their channel routing config.

3. Hot-reload implemented (Medium)

• channel_routing_arc (Arc<RwLock>) shared between AgentDeps and the SIGHUP handler
• SIGHUP handler now calls load_from_store() with the correct owner ID and writes the new config into the shared RwLock
• Subsequent dispatcher turns see the updated routing policy without restart

All checks pass (cargo check, clippy, fmt, 17 channel_routing tests).

[zmanian]

Re-Review -- APPROVE

All 3 blockers addressed in 487cfc2:

1. DM bypass channel names -- Fixed. Now uses "gateway" (not "web"), checks Slack metadata channel.starts_with('D'), checks Telegram chat_type == "private". filter_tool_defs accepts metadata parameter.
2. Owner scope -- Fixed. Uses config.owner_id instead of "default" at both startup and SIGHUP reload.
3. Hot-reload -- Fixed. SIGHUP handler now loads fresh config from DB, acquires write lock, and replaces the value. Complete reload path.

CI green across all configurations.

Minor note (non-blocking)

The changed detection (new_routing.is_some() != guard.is_some()) only detects presence/absence, not content changes. The new config is written regardless, but the log message may say "unchanged" when content actually changed.