Gpt 5p4 Prompting Guide

# GPT-5.4 prompting upgrade guide

Use this guide when prompts written for older models need to be adapted for GPT-5.4 during an upgrade. Start lean: keep the model-string change narrow, preserve the original task intent, and add only the smallest prompt changes needed to recover behavior.

## Default upgrade posture

- Start with `model string only` whenever the old prompt is already short, explicit, and task-bounded.
- Move to `model string + light prompt rewrite` only when regressions appear in completeness, persistence, citation quality, verification, or verbosity.
- Prefer one or two targeted prompt additions over a broad rewrite.
- Treat reasoning effort as a last-mile knob. Start lower, then increase only after prompt-level fixes and evals.
- Before increasing reasoning effort, first add a completeness contract, a verification loop, and tool persistence rules - depending on the usage case.
- If the workflow clearly depends on implementation changes rather than prompt changes, treat it as blocked for prompt-only upgrade guidance.
- Do not classify a case as blocked just because the workflow uses tools; block only if the upgrade requires changing tool definitions, wiring, or other implementation details.

## Behavioral differences to account for

Current GPT-5.4 upgrade guidance suggests these strengths:

- stronger personality and tone adherence, with less drift over long answers
- better long-horizon and agentic workflow stamina
- stronger spreadsheet, finance, and formatting tasks
- more efficient tool selection and fewer unnecessary calls by default
- stronger structured generation and classification reliability

The main places where prompt guidance still helps are:

- retrieval-heavy workflows that need persistent tool use and explicit completeness
- research and citation discipline
- verification before irreversible or high-impact actions
- terminal and tool workflow hygiene
- defaults and implied follow-through
- verbosity control for compact, information-dense answers

Start with the smallest set of instructions that preserves correctness. Add the prompt blocks below only for workflows that actually need them.

## Prompt rewrite patterns

| Older prompt pattern | GPT-5.4 adjustment | Why | Example addition |
| --- | --- | --- | --- |
| Long, repetitive instructions that compensate for weaker instruction following | Remove duplicate scaffolding and keep only the constraints that materially change behavior | GPT-5.4 usually needs less repeated steering | Replace repeated reminders with one concise rule plus a verification block |
| Fast assistant prompt with no verbosity control | Keep the prompt as-is first; add a verbosity clamp only if outputs become too long | Many GPT-4o or GPT-4.1 upgrades work with just a model-string swap | Add `output_verbosity_spec` only after a verbosity regression |
| Tool-heavy agent prompt that assumes the model will keep searching until complete | Add persistence and verification rules | GPT-5.4 may use fewer tool calls by default for efficiency | Add `tool_persistence_rules` and `verification_loop` |
| Tool-heavy workflow where later actions depend on earlier lookup or retrieval | Add prerequisite and missing-context rules before action steps | GPT-5.4 benefits from explicit dependency-aware routing when context is still thin | Add `dependency_checks` and `missing_context_gating` |
| Retrieval workflow with several independent lookups | Add selective parallelism guidance | GPT-5.4 is strong at parallel tool use, but should not parallelize dependent steps | Add `parallel_tool_calling` |
| Batch workflow prompt that often misses items | Add an explicit completeness contract | Item accounting benefits from direct instruction | Add `completeness_contract` |
| Research prompt that needs grounding and citation discipline | Add research, citation, and empty-result recovery blocks | Multi-pass retrieval is stronger when the model is told how to react to weak or empty search results | Add `research_mode`, `citation_rules`, and `empty_result_handling`; add `tool_persistence_rules` when retrieval tools are already in use |
| Coding or terminal prompt with shell misuse or early stop failures | Keep the same tool surface and add terminal hygiene and verification instructions | Tool-using coding workflows are not blocked just because tools exist; they usually need better prompt steering, not host rewiring | Add `terminal_tool_hygiene` and `verification_loop`, optionally `tool_persistence_rules` |
| Multi-agent or support-triage workflow with escalation or completeness requirements | Add one lightweight control block for persistence, completeness, or verification | GPT-5.4 can be more efficient by default, so multi-step support flows benefit from an explicit completion or verification contract | Add at least one of `tool_persistence_rules`, `completeness_contract`, or `verification_loop` |

## Prompt blocks

Use these selectively. Do not add all of them by default.

### `output_verbosity_spec`

Use when:

- the upgraded model gets too wordy
- the host needs compact, information-dense answers
- the workflow benefits from a short overview plus a checklist