OpenAI’s first DevDay (November 6th) packed significant announcements: GPT-4 Turbo, custom GPTs, the Assistants API, and more. For developers building AI applications, these changes shift what’s possible. Let me break down what matters.
Key Announcements
GPT-4 Turbo
gpt4_turbo:
context_window:
before: 8K or 32K tokens
after: 128K tokens
impact: Entire codebases, long documents fit in context
knowledge_cutoff:
before: September 2021
after: April 2023
impact: More current information
pricing:
input: $0.01/1K tokens (3x cheaper than GPT-4)
output: $0.03/1K tokens (2x cheaper)
impact: Significantly reduced costs
capabilities:
- JSON mode (guaranteed valid JSON)
- Seed parameter (reproducible outputs)
- Improved function calling
- Better instruction following
Assistants API
assistants_api:
what: Stateful, tool-using agents as a service
key_features:
persistent_threads:
- Conversation history managed by OpenAI
- No manual context management
- Messages persist across requests
built_in_tools:
code_interpreter:
- Execute Python code
- Generate visualizations
- Process files
retrieval:
- Upload documents
- Automatic RAG
- No vector DB needed
function_calling:
- Call your APIs
- Same as before, improved
implications:
- Lower barrier to building agents
- Reduced infrastructure needs
- But: less control, vendor lock-in
Custom GPTs
custom_gpts:
what: No-code custom ChatGPT versions
features:
- Custom instructions
- Knowledge files
- Actions (API integrations)
- Shareable/monetizable
developer_impact:
positive:
- Rapid prototyping
- Distribution channel
- Monetization opportunity
concerns:
- Limited customization
- Platform dependency
- Competition from simple solutions
Technical Deep Dives
Using GPT-4 Turbo
import openai
# New model with 128K context
response = openai.ChatCompletion.create(
model="gpt-4-1106-preview", # GPT-4 Turbo
messages=[
{"role": "system", "content": "You are a helpful assistant."},
{"role": "user", "content": long_document} # Can now be huge
],
response_format={"type": "json_object"}, # Guaranteed JSON
seed=42 # Reproducible outputs
)
Assistants API
import openai
# Create an assistant
assistant = openai.beta.assistants.create(
name="Data Analyst",
instructions="You analyze data and create visualizations.",
model="gpt-4-1106-preview",
tools=[
{"type": "code_interpreter"},
{"type": "retrieval"}
]
)
# Upload files for retrieval
file = openai.files.create(
file=open("data.csv", "rb"),
purpose="assistants"
)
# Create a thread (conversation)
thread = openai.beta.threads.create()
# Add a message
message = openai.beta.threads.messages.create(
thread_id=thread.id,
role="user",
content="Analyze the sales data and create a chart",
file_ids=[file.id]
)
# Run the assistant
run = openai.beta.threads.runs.create(
thread_id=thread.id,
assistant_id=assistant.id
)
# Wait for completion and get messages
# (In practice, use polling or streaming)
Strategic Implications
What This Changes
strategic_shifts:
rag_simplified:
before: Build vector DB, embedding pipeline, retrieval
after: Upload files, OpenAI handles RAG
consideration: Trade-off control for simplicity
agent_infrastructure:
before: Build thread management, tool execution
after: Assistants API handles state
consideration: Lock-in vs. development speed
cost_structure:
before: GPT-4 expensive, limit usage
after: 3x cheaper, more viable for production
consideration: New use cases become feasible
context_strategies:
before: Carefully manage context, summarize
after: 128K tokens, often fits everything
consideration: Simpler architectures possible
Build vs. Buy Decisions
build_vs_buy_reevaluation:
use_assistants_api_when:
- Rapid prototyping
- Simple use cases
- Limited engineering resources
- Acceptable vendor lock-in
build_your_own_when:
- Need fine-grained control
- Specific retrieval requirements
- Multi-model strategies
- Data sovereignty requirements
- Custom evaluation needs
hybrid_approach:
- Use Assistants for simple features
- Custom for core differentiators
- Evaluate as capabilities evolve
Action Items
For Existing Applications
existing_app_actions:
immediate:
- Test GPT-4 Turbo compatibility
- Evaluate cost savings
- Try JSON mode for structured outputs
short_term:
- Consider context window expansion opportunities
- Evaluate Assistants API for appropriate features
- Update rate limit handling for new models
evaluate:
- RAG system: keep custom or migrate?
- Agent infrastructure: rebuild on Assistants?
- Cost/benefit of migration
For New Projects
new_project_decisions:
start_with:
- GPT-4 Turbo as default
- JSON mode for structured output
- Assistants API for prototyping
consider:
- Is 128K context enough? (Usually yes)
- Do we need custom retrieval? (Often no)
- Can we accept OpenAI dependencies?
architecture:
- Simpler is now often better
- Built-in features before custom
- Abstract for future flexibility
Key Takeaways
- GPT-4 Turbo: 128K context, 3x cheaper, JSON mode, seeds
- Assistants API: Managed agents with code interpreter and retrieval
- Custom GPTs: No-code chatbots, potential distribution channel
- 128K context simplifies many RAG architectures
- Assistants API trades control for simplicity
- Cost reduction enables new use cases
- Evaluate build vs. buy decisions with new capabilities
- Start with built-in features, customize when needed
- Platform lock-in is the trade-off for convenience
- The gap between prototype and production narrowed
DevDay moved the baseline. Rebuild your assumptions.