feat: add GPT/Codex execution discipline guidance for tool persistence (#5414)

Adds OPENAI_MODEL_EXECUTION_GUIDANCE — XML-tagged behavioral guidance
injected for GPT and Codex models alongside the existing tool-use
enforcement. Targets four specific failure modes:

- <tool_persistence>: retry on empty/partial results instead of giving up
- <prerequisite_checks>: do discovery/lookup before jumping to final action
- <verification>: check correctness/grounding/formatting before finalizing
- <missing_context>: use lookup tools instead of hallucinating

Follows the same injection pattern as GOOGLE_MODEL_OPERATIONAL_GUIDANCE
for Gemini/Gemma models. Inspired by OpenClaw PR #38953 and OpenAI's
GPT-5.4 prompting guide patterns.

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 = (