feat(messaging): add Signal adapter via signal-cli JSON-RPC daemon

prompts/en/adapters/signal.md.j2

@@ -0,0 +1,10 @@
+## Signal Adapter Guidance
+
+You are in a Signal conversation. Signal supports cross-channel messaging — you can send messages to other Signal users and groups using the `send_message_to_another_channel` tool.
+
+**Supported Signal targets:**
+- `signal:uuid:{uuid}` — Send to a Signal user by their UUID
+- `signal:group:{group_id}` — Send to a Signal group
+- `signal:+{phone}` or `signal:e164:+{phone}` — Send to a Signal user by phone number
+
+Use this when the user asks you to message someone else on Signal or post to a Signal group.

prompts/en/tools/send_message_description.md.j2

@@ -1 +1,6 @@
 Send a message to a DIFFERENT channel than the one you are currently in. Use this for cross-channel delivery — reminders, notifications, or when the user asks you to post something in another channel or DM them. Do NOT use this to reply in the current conversation — use the `reply` tool for that. Target channels by name or ID from the available channels in your context.
+
+For Signal messaging, you can use these explicit targets:
+- `signal:uuid:{uuid}` - Send to a Signal user by their UUID
+- `signal:group:{group_id}` - Send to a Signal group
+- `signal:+{phone}` or `signal:e164:+{phone}` — Send to a Signal user by phone number

src/agent/channel.rs

@@ -823,7 +823,7 @@ impl Channel {
         }
         let supported_source = matches!(
             message.source.as_str(),
-            "telegram" | "discord" | "slack" | "twitch"
+            "telegram" | "discord" | "slack" | "twitch" | "signal"
         );
         if !supported_source {
             return Ok(false);
@@ -1202,11 +1202,13 @@ impl Channel {
             self.conversation_id = Some(first.conversation_id.clone());
         }
 
+        // Track source adapter from the first non-system message
+        // Prefer message.adapter (full adapter string like "signal:work") over message.source
         if self.source_adapter.is_none()
             && let Some(first) = messages.first()
             && first.source != "system"
         {
-            self.source_adapter = Some(first.source.clone());
+            self.source_adapter = first.adapter.clone().or_else(|| Some(first.source.clone()));
         }
 
         // Capture conversation context from the first message
@@ -1408,6 +1410,13 @@ impl Channel {
             .build_system_prompt_with_coalesce(message_count, elapsed_secs, unique_sender_count)
             .await?;
 
+        // Extract adapter from messages (prefer explicit message.adapter, fall back to stored source_adapter)
+        // This preserves per-message adapter for Signal named instances (e.g., "signal:work")
+        let batch_adapter = messages
+            .iter()
+            .find_map(|m| m.adapter.as_deref())
+            .or(self.source_adapter.as_deref());
+
         {
             let mut reply_target = self.state.reply_target_message_id.write().await;
             *reply_target = messages.iter().rev().find_map(extract_message_id);
@@ -1421,6 +1430,7 @@ impl Channel {
                 &conversation_id,
                 attachment_parts,
                 false, // not a retrigger
+                batch_adapter,
             )
             .await?;
 
@@ -1552,8 +1562,13 @@ impl Channel {
             self.conversation_id = Some(message.conversation_id.clone());
         }
 
+        // Track source adapter from non-system messages
+        // Prefer message.adapter (full adapter string like "signal:work") over message.source
         if self.source_adapter.is_none() && message.source != "system" {
-            self.source_adapter = Some(message.source.clone());
+            self.source_adapter = message
+                .adapter
+                .clone()
+                .or_else(|| Some(message.source.clone()));
         }
 
         let (raw_text, attachments) = match &message.content {
@@ -1743,13 +1758,18 @@ impl Channel {
             Vec::new()
         };
 
+        let adapter = message
+            .adapter
+            .as_deref()
+            .or_else(|| self.current_adapter());
         let (result, skip_flag, replied_flag, retrigger_reply_preserved) = self
             .run_agent_turn(
                 &user_text,
                 &system_prompt,
                 &message.conversation_id,
                 attachment_content,
                 is_retrigger,
+                adapter,
             )
             .await?;
 
@@ -1765,7 +1785,7 @@ impl Channel {
             && !replied_flag.load(std::sync::atomic::Ordering::Relaxed)
             && matches!(
                 message.source.as_str(),
-                "discord" | "telegram" | "slack" | "twitch"
+                "discord" | "telegram" | "slack" | "twitch" | "signal"
             )
         {
             self.send_builtin_text(
@@ -2171,6 +2191,7 @@ impl Channel {
         conversation_id: &str,
         attachment_content: Vec<UserContent>,
         is_retrigger: bool,
+        adapter: Option<&str>,
     ) -> Result<(
         std::result::Result<String, rig::completion::PromptError>,
         crate::tools::SkipFlag,
@@ -2198,6 +2219,7 @@ impl Channel {
             self.deps.cron_tool.clone(),
             send_agent_message_tool,
             allow_direct_reply,
+            adapter.map(|s| s.to_string()),
         )
         .await
         {
@@ -2582,6 +2604,12 @@ impl Channel {
                     .channel_errors_total
                     .with_label_values(&[metrics_agent_id, metrics_channel_type, "llm_error"])
                     .inc();
+                // Send error to user so they know something went wrong
+                let error_msg = format!("I encountered an error: {}", error);
+                self.response_tx
+                    .send(OutboundResponse::Text(error_msg))
+                    .await
+                    .ok();
                 tracing::error!(channel_id = %self.id, %error, "channel LLM call failed");
             }
         }

src/agent/channel_history.rs

@@ -317,7 +317,17 @@ pub(crate) fn format_user_message(
         raw_text
     };
 
-    format!("{display_name}{bot_tag}{reply_context} [{timestamp_text}]: {text_content}")
+    let sender_context = message
+        .metadata
+        .get("sender_context")
+        .and_then(|v| v.as_str())
+        .filter(|s| !s.is_empty())
+        .map(|s| format!(" {s}"))
+        .unwrap_or_default();
+
+    format!(
+        "{display_name}{bot_tag}{reply_context}{sender_context} [{timestamp_text}]: {text_content}"
+    )
 }
 
 pub(crate) fn format_batched_user_message(

src/config.rs

@@ -15,7 +15,7 @@ pub(crate) use load::resolve_env_value;
 pub use load::set_resolve_secrets_store;
 pub use onboarding::run_onboarding;
 pub use permissions::{
-    DiscordPermissions, SlackPermissions, TelegramPermissions, TwitchPermissions,
+    DiscordPermissions, SignalPermissions, SlackPermissions, TelegramPermissions, TwitchPermissions,
 };
 pub(crate) use providers::default_provider_config;
 pub use runtime::RuntimeConfig;
@@ -1539,6 +1539,7 @@ maintenance_merge_similarity_threshold = 1.1
             email: None,
             webhook: None,
             twitch: None,
+            signal: None,
         };
         let bindings = vec![
             Binding {
@@ -1548,6 +1549,7 @@ maintenance_merge_similarity_threshold = 1.1
                 guild_id: None,
                 workspace_id: None,
                 chat_id: None,
+
                 channel_ids: vec![],
                 require_mention: false,
                 dm_allowed_users: vec![],
@@ -1559,6 +1561,7 @@ maintenance_merge_similarity_threshold = 1.1
                 guild_id: None,
                 workspace_id: None,
                 chat_id: None,
+
                 channel_ids: vec![],
                 require_mention: false,
                 dm_allowed_users: vec![],
@@ -1581,6 +1584,7 @@ maintenance_merge_similarity_threshold = 1.1
             email: None,
             webhook: None,
             twitch: None,
+            signal: None,
         };
         let bindings = vec![Binding {
             agent_id: "main".into(),
@@ -1643,6 +1647,7 @@ maintenance_merge_similarity_threshold = 1.1
             }),
             webhook: None,
             twitch: None,
+            signal: None,
         };
         let bindings = vec![Binding {
             agent_id: "main".into(),
@@ -1677,6 +1682,7 @@ maintenance_merge_similarity_threshold = 1.1
             email: None,
             webhook: None,
             twitch: None,
+            signal: None,
         };
         // Binding targets default adapter, but no default credentials exist
         let bindings = vec![Binding {

src/config/load.rs

@@ -14,10 +14,10 @@ use super::{
     CoalesceConfig, CompactionConfig, Config, CortexConfig, CronDef, DefaultsConfig, DiscordConfig,
     DiscordInstanceConfig, EmailConfig, EmailInstanceConfig, GroupDef, HumanDef, IngestionConfig,
     LinkDef, LlmConfig, McpServerConfig, McpTransport, MemoryPersistenceConfig, MessagingConfig,
-    MetricsConfig, OpenCodeConfig, ProjectsConfig, ProviderConfig, SlackCommandConfig, SlackConfig,
-    SlackInstanceConfig, TelegramConfig, TelegramInstanceConfig, TelemetryConfig, TwitchConfig,
-    TwitchInstanceConfig, WarmupConfig, WebhookConfig, normalize_adapter,
-    validate_named_messaging_adapters,
+    MetricsConfig, OpenCodeConfig, ProjectsConfig, ProviderConfig, SignalConfig,
+    SignalInstanceConfig, SlackCommandConfig, SlackConfig, SlackInstanceConfig, TelegramConfig,
+    TelegramInstanceConfig, TelemetryConfig, TwitchConfig, TwitchInstanceConfig, WarmupConfig,
+    WebhookConfig, normalize_adapter, validate_named_messaging_adapters,
 };
 use crate::error::{ConfigError, Result};
 
@@ -2148,6 +2148,57 @@ impl Config {
                     trigger_prefix: t.trigger_prefix,
                 })
             }),
+            signal: toml.messaging.signal.and_then(|s| {
+                let instances = s
+                    .instances
+                    .into_iter()
+                    .map(|instance| {
+                        let http_url = instance.http_url.as_deref().and_then(resolve_env_value);
+                        let account = instance.account.as_deref().and_then(resolve_env_value);
+                        if instance.enabled && (http_url.is_none() || account.is_none()) {
+                            tracing::warn!(
+                                adapter = %instance.name,
+                                "signal instance is enabled but http_url or account is missing/unresolvable — disabling"
+                            );
+                        }
+                        let has_credentials = http_url.is_some() && account.is_some();
+                        SignalInstanceConfig {
+                            name: instance.name,
+                            enabled: instance.enabled && has_credentials,
+                            http_url: http_url.unwrap_or_default(),
+                            account: account.unwrap_or_default(),
+                            dm_allowed_users: instance.dm_allowed_users,
+                            group_ids: instance.group_ids,
+                            group_allowed_users: instance.group_allowed_users,
+                            ignore_stories: instance.ignore_stories,
+                        }
+                    })
+                    .collect::<Vec<_>>();
+
+                let http_url = std::env::var("SIGNAL_HTTP_URL")
+                    .ok()
+                    .or_else(|| s.http_url.as_deref().and_then(resolve_env_value));
+                let account = std::env::var("SIGNAL_ACCOUNT")
+                    .ok()
+                    .or_else(|| s.account.as_deref().and_then(resolve_env_value));
+
+                if (http_url.is_none() || account.is_none())
+                    && !instances.iter().any(|inst| inst.enabled)
+                {
+                    return None;
+                }
+
+                Some(SignalConfig {
+                    enabled: s.enabled,
+                    http_url: http_url.unwrap_or_default(),
+                    account: account.unwrap_or_default(),
+                    instances,
+                    dm_allowed_users: s.dm_allowed_users,
+                    group_ids: s.group_ids,
+                    group_allowed_users: s.group_allowed_users,
+                    ignore_stories: s.ignore_stories,
+                })
+            }),
         };
 
         let bindings: Vec<Binding> = toml