feat(ava): subagent hardening with audit logging

Based on Anthropic's effective harnesses research.

New modules:
- Omni/Agent/AuditLog.hs: JSONL audit logging with SubagentId linking
- Omni/Agent/Tools/AvaLogs.hs: Tool for Ava to query her own logs
- Omni/Agent/Subagent/HARDENING.md: Design documentation

Key features:
- SubagentHandle with TVar status for async execution and polling
- spawnSubagentAsync, querySubagentStatus, waitSubagent, cancelSubagent
- User confirmation: spawn_subagent requires confirmed=true after approval
- Audit logs stored in $AVA_DATA_ROOT/logs/{ava,subagents}/
- CLI: ava logs [--last=N] [<subagent_id>]
- read_ava_logs tool for Ava self-diagnosis

Tasks: t-267, t-268, t-269, t-270, t-271

1 files changed, 52 insertions, 5 deletions

diff --git a/Omni/Ava.hs b/Omni/Ava.hs
index 0788658..3640fc2 100755
--- a/Omni/Ava.hs
+++ b/Omni/Ava.hs
@@ -9,19 +9,27 @@
 --   ava                    # Uses TELEGRAM_BOT_TOKEN env var
 --   ava --token=XXX        # Explicit token
 --   ava --model=MODEL      # Override LLM model
+--   ava logs [--last=N] [SUBAGENT_ID]  # View audit logs
 --
 -- : out ava
 -- : dep aeson
 -- : dep http-conduit
 -- : dep stm
+-- : dep time
+-- : dep uuid
 module Omni.Ava where
 
 import Alpha
+import qualified Data.Aeson as Aeson
 import qualified Data.Text as Text
+import qualified Data.Text.IO as TextIO
+import qualified Data.Time as Time
+import qualified Omni.Agent.AuditLog as AuditLog
 import qualified Omni.Agent.Telegram as Telegram
 import qualified Omni.Cli as Cli
 import qualified Omni.Test as Test
 import qualified System.Console.Docopt as Docopt
+import qualified System.Directory as Dir
 import qualified System.IO as IO
 
 main :: IO ()
@@ -43,21 +51,60 @@ ava - AI assistant via Telegram
 
 Usage:
   ava [--token=TOKEN] [--model=MODEL]
+  ava logs [--last=N] [<subagent_id>]
   ava test
   ava (-h | --help)
 
 Options:
-  -h --help       Show this help
-  --token=TOKEN   Telegram bot token (or use TELEGRAM_BOT_TOKEN env)
-  --model=MODEL   LLM model to use [default: anthropic/claude-sonnet-4]
+  -h --help         Show this help
+  --token=TOKEN     Telegram bot token (or use TELEGRAM_BOT_TOKEN env)
+  --model=MODEL     LLM model to use [default: anthropic/claude-sonnet-4]
+  --last=N          Number of recent log entries to show [default: 50]
+  <subagent_id>     Show logs for a specific subagent (e.g. S-abc123)
 |]
 
 move :: Cli.Arguments -> IO ()
 move args = do
   IO.hSetBuffering IO.stdout IO.LineBuffering
   IO.hSetBuffering IO.stderr IO.LineBuffering
-  let maybeToken = fmap Text.pack (Cli.getArg args (Cli.longOption "token"))
-  Telegram.startBot maybeToken
+  if args `Cli.has` Cli.command "logs"
+    then showLogs args
+    else do
+      let maybeToken = fmap Text.pack (Cli.getArg args (Cli.longOption "token"))
+      Telegram.startBot maybeToken
+
+showLogs :: Cli.Arguments -> IO ()
+showLogs args = do
+  let maybeSubagentId = Cli.getArg args (Cli.argument "subagent_id")
+  let lastN = fromMaybe 50 (readMaybe =<< Cli.getArg args (Cli.longOption "last"))
+
+  case maybeSubagentId of
+    Just sidStr -> do
+      let sid = AuditLog.SubagentId (Text.pack sidStr)
+      let path = AuditLog.subagentLogPath sid
+      exists <- Dir.doesFileExist path
+      if exists
+        then do
+          entries <- AuditLog.readSubagentLogs sid
+          putText <| "=== Subagent " <> Text.pack sidStr <> " (" <> tshow (length entries) <> " entries) ==="
+          traverse_ printLogEntry entries
+        else putText <| "No logs found for subagent: " <> Text.pack sidStr
+    Nothing -> do
+      entries <- AuditLog.getRecentAvaLogs lastN
+      today <- Time.utctDay </ Time.getCurrentTime
+      putText <| "=== Ava logs for " <> Text.pack (Time.formatTime Time.defaultTimeLocale "%Y-%m-%d" today) <> " (last " <> tshow lastN <> ") ==="
+      traverse_ printLogEntry entries
+
+printLogEntry :: AuditLog.AuditLogEntry -> IO ()
+printLogEntry entry = do
+  let ts = Text.pack <| Time.formatTime Time.defaultTimeLocale "%H:%M:%S" (AuditLog.logTimestamp entry)
+  let evType = tshow (AuditLog.logEventType entry)
+  let agent = AuditLog.unAgentId (AuditLog.logAgentId entry)
+  let content = case AuditLog.logContent entry of
+        Aeson.String t -> Text.take 100 t
+        Aeson.Object _ -> "<object>"
+        _ -> "<value>"
+  TextIO.putStrLn <| "[" <> ts <> "] " <> agent <> " | " <> evType <> ": " <> content
 
 test :: Test.Tree
 test =