diff --git a/agent/prompt_builder.py b/agent/prompt_builder.py
index fbb5f0fa0..80af3b64d 100644
--- a/agent/prompt_builder.py
+++ b/agent/prompt_builder.py
@@ -189,6 +189,46 @@ TOOL_USE_ENFORCEMENT_GUIDANCE = (
 # Add new patterns here when a model family needs explicit steering.
 TOOL_USE_ENFORCEMENT_MODELS = ("gpt", "codex", "gemini", "gemma")
 
+# OpenAI GPT/Codex-specific execution guidance.  Addresses known failure modes
+# where GPT models abandon work on partial results, skip prerequisite lookups,
+# hallucinate instead of using tools, and declare "done" without verification.
+# Inspired by patterns from OpenAI's GPT-5.4 prompting guide & OpenClaw PR #38953.
+OPENAI_MODEL_EXECUTION_GUIDANCE = (
+    "# Execution discipline\n"
+    "<tool_persistence>\n"
+    "- Use tools whenever they improve correctness, completeness, or grounding.\n"
+    "- Do not stop early when another tool call would materially improve the result.\n"
+    "- If a tool returns empty or partial results, retry with a different query or "
+    "strategy before giving up.\n"
+    "- Keep calling tools until: (1) the task is complete, AND (2) you have verified "
+    "the result.\n"
+    "</tool_persistence>\n"
+    "\n"
+    "<prerequisite_checks>\n"
+    "- Before taking an action, check whether prerequisite discovery, lookup, or "
+    "context-gathering steps are needed.\n"
+    "- Do not skip prerequisite steps just because the final action seems obvious.\n"
+    "- If a task depends on output from a prior step, resolve that dependency first.\n"
+    "</prerequisite_checks>\n"
+    "\n"
+    "<verification>\n"
+    "Before finalizing your response:\n"
+    "- Correctness: does the output satisfy every stated requirement?\n"
+    "- Grounding: are factual claims backed by tool outputs or provided context?\n"
+    "- Formatting: does the output match the requested format or schema?\n"
+    "- Safety: if the next step has side effects (file writes, commands, API calls), "
+    "confirm scope before executing.\n"
+    "</verification>\n"
+    "\n"
+    "<missing_context>\n"
+    "- If required context is missing, do NOT guess or hallucinate an answer.\n"
+    "- Use the appropriate lookup tool when missing information is retrievable "
+    "(search_files, web_search, read_file, etc.).\n"
+    "- Ask a clarifying question only when the information cannot be retrieved by tools.\n"
+    "- If you must proceed with incomplete information, label assumptions explicitly.\n"
+    "</missing_context>"
+)
+
 # Gemini/Gemma-specific operational guidance, adapted from OpenCode's gemini.txt.
 # Injected alongside TOOL_USE_ENFORCEMENT_GUIDANCE when the model is Gemini or Gemma.
 GOOGLE_MODEL_OPERATIONAL_GUIDANCE = (
diff --git a/run_agent.py b/run_agent.py
index 619796c97..9aca26067 100644
--- a/run_agent.py
+++ b/run_agent.py
@@ -90,7 +90,7 @@ from agent.model_metadata import (
 from agent.context_compressor import ContextCompressor
 from agent.subdirectory_hints import SubdirectoryHintTracker
 from agent.prompt_caching import apply_anthropic_cache_control
-from agent.prompt_builder import build_skills_system_prompt, build_context_files_prompt, load_soul_md, TOOL_USE_ENFORCEMENT_GUIDANCE, TOOL_USE_ENFORCEMENT_MODELS, DEVELOPER_ROLE_MODELS, GOOGLE_MODEL_OPERATIONAL_GUIDANCE
+from agent.prompt_builder import build_skills_system_prompt, build_context_files_prompt, load_soul_md, TOOL_USE_ENFORCEMENT_GUIDANCE, TOOL_USE_ENFORCEMENT_MODELS, DEVELOPER_ROLE_MODELS, GOOGLE_MODEL_OPERATIONAL_GUIDANCE, OPENAI_MODEL_EXECUTION_GUIDANCE
 from agent.usage_pricing import estimate_usage_cost, normalize_usage
 from agent.display import (
     KawaiiSpinner, build_tool_preview as _build_tool_preview,
@@ -2791,11 +2791,15 @@ class AIAgent:
                 _inject = any(p in model_lower for p in TOOL_USE_ENFORCEMENT_MODELS)
             if _inject:
                 prompt_parts.append(TOOL_USE_ENFORCEMENT_GUIDANCE)
+                _model_lower = (self.model or "").lower()
                 # Google model operational guidance (conciseness, absolute
                 # paths, parallel tool calls, verify-before-edit, etc.)
-                _model_lower = (self.model or "").lower()
                 if "gemini" in _model_lower or "gemma" in _model_lower:
                     prompt_parts.append(GOOGLE_MODEL_OPERATIONAL_GUIDANCE)
+                # OpenAI GPT/Codex execution discipline (tool persistence,
+                # prerequisite checks, verification, anti-hallucination).
+                if "gpt" in _model_lower or "codex" in _model_lower:
+                    prompt_parts.append(OPENAI_MODEL_EXECUTION_GUIDANCE)
 
         # so it can refer the user to them rather than reinventing answers.
 
diff --git a/tests/agent/test_prompt_builder.py b/tests/agent/test_prompt_builder.py
index 791f7ea0e..ce8084709 100644
--- a/tests/agent/test_prompt_builder.py
+++ b/tests/agent/test_prompt_builder.py
@@ -23,6 +23,7 @@ from agent.prompt_builder import (
     DEFAULT_AGENT_IDENTITY,
     TOOL_USE_ENFORCEMENT_GUIDANCE,
     TOOL_USE_ENFORCEMENT_MODELS,
+    OPENAI_MODEL_EXECUTION_GUIDANCE,
     MEMORY_GUIDANCE,
     SESSION_SEARCH_GUIDANCE,
     PLATFORM_HINTS,
@@ -1021,6 +1022,41 @@ class TestToolUseEnforcementGuidance:
         assert isinstance(TOOL_USE_ENFORCEMENT_MODELS, tuple)
 
 
+class TestOpenAIModelExecutionGuidance:
+    """Tests for GPT/Codex-specific execution discipline guidance."""
+
+    def test_guidance_covers_tool_persistence(self):
+        text = OPENAI_MODEL_EXECUTION_GUIDANCE.lower()
+        assert "tool_persistence" in text
+        assert "retry" in text
+        assert "empty" in text or "partial" in text
+
+    def test_guidance_covers_prerequisite_checks(self):
+        text = OPENAI_MODEL_EXECUTION_GUIDANCE.lower()
+        assert "prerequisite" in text
+        assert "dependency" in text
+
+    def test_guidance_covers_verification(self):
+        text = OPENAI_MODEL_EXECUTION_GUIDANCE.lower()
+        assert "verification" in text or "verify" in text
+        assert "correctness" in text
+
+    def test_guidance_covers_missing_context(self):
+        text = OPENAI_MODEL_EXECUTION_GUIDANCE.lower()
+        assert "missing_context" in text or "missing context" in text
+        assert "hallucinate" in text or "guess" in text
+
+    def test_guidance_uses_xml_tags(self):
+        assert "<tool_persistence>" in OPENAI_MODEL_EXECUTION_GUIDANCE
+        assert "</tool_persistence>" in OPENAI_MODEL_EXECUTION_GUIDANCE
+        assert "<verification>" in OPENAI_MODEL_EXECUTION_GUIDANCE
+        assert "</verification>" in OPENAI_MODEL_EXECUTION_GUIDANCE
+
+    def test_guidance_is_string(self):
+        assert isinstance(OPENAI_MODEL_EXECUTION_GUIDANCE, str)
+        assert len(OPENAI_MODEL_EXECUTION_GUIDANCE) > 100
+
+
 # =========================================================================
 # Budget warning history stripping
 # =========================================================================