jr: add 'prompt' command to inspect agent system prompt

jr prompt <task-id> constructs and prints the full system prompt
that would be sent to the agent, including:
- Agent configuration (model, cost budget)
- Base instructions
- AGENTS.md content
- Relevant facts from knowledge base
- Retry/progress context if applicable

Useful for debugging agent behavior and token usage.

1 files changed, 17 insertions, 0 deletions

diff --git a/Omni/Jr.hs b/Omni/Jr.hs
index c35efa3..b60a029 100755
--- a/Omni/Jr.hs
+++ b/Omni/Jr.hs
@@ -54,6 +54,7 @@ jr
 Usage:
   jr task [<args>...]
   jr work [<task-id>]
+  jr prompt <task-id>
   jr web [--port=PORT]
   jr review [<task-id>] [--auto]
   jr loop [--delay=SECONDS]
@@ -67,6 +68,7 @@ Usage:
 Commands:
   task          Manage tasks
   work          Start a worker agent on a task
+  prompt        Show the system prompt that would be sent to the agent
   web           Start the web UI server
   review        Review a completed task (show diff, accept/reject)
   loop          Run autonomous work+review loop
@@ -94,6 +96,21 @@ move args
             Just p -> fromMaybe Web.defaultPort (readMaybe p)
             Nothing -> Web.defaultPort
       Web.run port
+  | args `Cli.has` Cli.command "prompt" = do
+      case Cli.getArg args (Cli.argument "task-id") of
+        Nothing -> do
+          IO.hPutStrLn IO.stderr "Error: task-id is required"
+          Exit.exitFailure
+        Just tidStr -> do
+          let tid = Text.pack tidStr
+          tasks <- TaskCore.loadTasks
+          case TaskCore.findTask tid tasks of
+            Nothing -> do
+              IO.hPutStrLn IO.stderr ("Error: task not found: " <> tidStr)
+              Exit.exitFailure
+            Just task -> do
+              prompt <- AgentWorker.buildFullPrompt task
+              putText prompt
   | args `Cli.has` Cli.command "work" = do
       -- Always run in current directory
       let path = "."