From 206f595f6639ff315c09dea6073ca6a3a7408e49 Mon Sep 17 00:00:00 2001
From: RyanRana <39924576+RyanRana@users.noreply.github.com>
Date: Mon, 18 May 2026 20:56:38 -0700
Subject: [PATCH] perf(prompt): cache kanban worker guidance at session init
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Salvages #24402 by @RyanRana. The KANBAN_GUIDANCE block (~835 tokens)
is session-static — the dispatcher decides at spawn time whether the
process is a kanban worker via the kanban_show tool's check_fn (gated
on HERMES_KANBAN_TASK env var). Re-checking 'kanban_show' in
valid_tool_names and re-loading the reference on every system-prompt
rebuild (init + each context compression) is wasted work.

Caches the resolved string on agent._kanban_worker_guidance once in
agent_init and consumes it in system_prompt.build_system_prompt(),
with a getattr fallback for code paths that bypass agent_init.
---
 agent/agent_init.py    | 14 ++++++++++++--
 agent/system_prompt.py |  8 ++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/agent/agent_init.py b/agent/agent_init.py
index 9b89028e3fa..a5d27c0b73d 100644
--- a/agent/agent_init.py
+++ b/agent/agent_init.py
@@ -828,7 +828,6 @@ def init_agent(
         tool_names = sorted(agent.valid_tool_names)
         if not agent.quiet_mode:
             print(f"🛠️  Loaded {len(agent.tools)} tools: {', '.join(tool_names)}")
-            
             # Show filtering info if applied
             if enabled_toolsets:
                 print(f"   ✅ Enabled toolsets: {', '.join(enabled_toolsets)}")
@@ -836,7 +835,18 @@ def init_agent(
                 print(f"   ❌ Disabled toolsets: {', '.join(disabled_toolsets)}")
     elif not agent.quiet_mode:
         print("🛠️  No tools loaded (all tools filtered out or unavailable)")
-    
+
+    # Kanban worker/orchestrator lifecycle guidance is session-static:
+    # the dispatcher decides at spawn time whether this process is a kanban
+    # worker (kanban_show tool is present iff HERMES_KANBAN_TASK is set).
+    # Resolving the ~835-token block once here avoids re-running the
+    # membership test + reference on every system-prompt rebuild
+    # (init + each context compression).
+    from agent.prompt_builder import KANBAN_GUIDANCE
+    agent._kanban_worker_guidance = (
+        KANBAN_GUIDANCE if "kanban_show" in agent.valid_tool_names else ""
+    )
+
     # Check tool requirements
     if agent.tools and not agent.quiet_mode:
         requirements = _ra().check_toolset_requirements()
diff --git a/agent/system_prompt.py b/agent/system_prompt.py
index a9815a2f2f4..bc29c9ef89a 100644
--- a/agent/system_prompt.py
+++ b/agent/system_prompt.py
@@ -111,8 +111,12 @@ def build_system_prompt_parts(agent: Any, system_message: Optional[str] = None)
     # Kanban worker/orchestrator lifecycle — only present when the
     # dispatcher spawned this process (kanban_show check_fn gates on
     # HERMES_KANBAN_TASK env var). Normal chat sessions never see
-    # this block.
-    if "kanban_show" in agent.valid_tool_names:
+    # this block. Resolved once at __init__ (see _kanban_worker_guidance).
+    _kanban_guidance = getattr(agent, "_kanban_worker_guidance", None)
+    if _kanban_guidance:
+        tool_guidance.append(_kanban_guidance)
+    elif _kanban_guidance is None and "kanban_show" in agent.valid_tool_names:
+        # Fallback for code paths that bypass agent_init (rare).
         tool_guidance.append(KANBAN_GUIDANCE)
     if tool_guidance:
         stable_parts.append(" ".join(tool_guidance))