Improve mock agent runner design

agents/runner/agent_runner.py

@@ -1,53 +1,132 @@
-"""Mock agent runner — simulates agent execution without real API calls."""
+"""
+Mock agent runner — simulates agent execution without real API calls.
+"""
 
-from pathlib import Path
 import json
-from typing import Optional
-
+import time
+import uuid
+from pathlib import Path
+from typing import Optional, Any
 
 TRACES_DIR = Path(__file__).parent.parent / "traces"
 
+# Mock Tools (no real APIs)
+def mock_fetch_emails(limit: int = 5) -> dict:
+    return {
+        "emails": [
+            {"from": "[email protected]", "subject": "Q3 Budget Review", "snippet": "Please review the attached budget..."},
+            {"from": "[email protected]", "subject": "Team standup notes", "snippet": "Action items from today's standup..."},
+            {"from": "[email protected]", "subject": "Invoice #4821", "snippet": "Please find attached invoice..."},
+        ][:limit]
+    }
+
+def mock_summarize_text(text: str) -> dict:
+    summary = text[:120].strip() + ("..." if len(text) > 120 else "")
+    return {"summary": summary, "word_count": len(text.split())}
+
+# Tool dispatch table
+TOOL_DISPATCH = {
+    "fetch_emails": mock_fetch_emails,
+    "summarize_text": mock_summarize_text,
+}
+
+# email_summarizer
+
+def email_chain(user_input: dict, prev: dict) -> list[tuple[str, dict]]:
+    return [
+        ("fetch_emails", {"limit": user_input.get("limit", 5)}),
+        ("summarize_text", {
+            "text": " | ".join(
+                e["snippet"] for e in prev.get("fetch_emails", {}).get("emails", [])
+            )
+        }),
+    ]
+
+AGENT_CHAINS = {
+    "email_summarizer": email_chain,
+}
+
+# Final Output Builder
+def build_final_output(agent_id: str, outputs: dict) -> str:
+    if agent_id == "email_summarizer":
+        emails = outputs["fetch_emails"]["emails"]
+        summary = outputs["summarize_text"]["summary"]
+        return f"Summarized {len(emails)} emails: {summary}"
+    return f"Agent '{agent_id}' executed successfully."
 
+# Runner
 def run_agent(agent_id: str, user_input: dict) -> dict:
-    """Simulate running an agent with the given input.
-
-    TODO: Implement full simulation flow:
-      1. Load agent manifest
-      2. Identify required tools
-      3. Call mock tools (return canned responses)
-      4. Build trace steps
-      5. Generate final output
-      6. Save run history
-
-    For MVP skeleton, return a placeholder response.
-    """
-    return {
+    run_id = str(uuid.uuid4())[:8]
+    start = time.time()
+    trace = []
+    outputs = {}
+
+    if agent_id not in AGENT_CHAINS:
+        return {
+            "agent_id": agent_id,
+            "status": "error",
+            "message": f"Agent '{agent_id}' not found.",
+            "input_received": user_input,
+        }
+
+    chain_builder = AGENT_CHAINS[agent_id]
+    tool_steps = chain_builder(user_input, {})
+
+    for i, (tool_id, _) in enumerate(tool_steps):
+        refreshed_steps = chain_builder(user_input, outputs)
+        _, kwargs = refreshed_steps[i]
+
+        tool_fn = TOOL_DISPATCH[tool_id]
+        t0 = time.time()
+        output = tool_fn(**kwargs)
+        latency = int((time.time() - t0) * 1000) + 15
+
+        outputs[tool_id] = output
+        trace.append({
+            "step": i + 1,
+            "tool_id": tool_id,
+            "input": kwargs,
+            "output": output,
+            "status": "success",
+            "latency_ms": latency,
+        })
+
+    final_output = build_final_output(agent_id, outputs)
+    duration = int((time.time() - start) * 1000)
+
+    result = {
+        "run_id": run_id,
         "agent_id": agent_id,
-        "status": "simulated",
-        "message": "TODO: Implement agent runner simulation",
-        "input_received": user_input,
+        "user_input": user_input,
+        "final_output": final_output,
+        "status": "success",
+        "trace": trace,
+        "duration_ms": duration,
     }
 
+    _save_trace(result)
+    return result
 
+# Trace Loader
 def get_trace_for_agent(agent_id: str) -> Optional[dict]:
-    """Load a pre-built mock trace for an agent if one exists.
-
-    TODO: Support loading traces by run_id
-    TODO: Support listing all traces for an agent
-    """
     trace_map = {
         "email_summarizer": "email_summarizer_trace.json",
-        "github_issue_triage": "github_issue_triage_trace.json",
-        "meeting_notes": "meeting_notes_trace.json",
     }
 
     trace_file = trace_map.get(agent_id)
     if not trace_file:
         return None
 
-    trace_path = TRACES_DIR / trace_file
-    if not trace_path.exists():
+    path = TRACES_DIR / trace_file
+    if not path.exists():
         return None
 
-    with open(trace_path, encoding="utf-8") as f:
+    with open(path, encoding="utf-8") as f:
         return json.load(f)
+
+# Save Trace
+def _save_trace(result: dict) -> None:
+    TRACES_DIR.mkdir(parents=True, exist_ok=True)
+    path = TRACES_DIR / f"{result['agent_id']}_{result['run_id']}.json"
+    path.write_text(json.dumps(result, indent=2), encoding="utf-8")
+