refactor: replace direct ChatOpenAI usage with provider-agnostic get_chat_model function

[aryanraj2713]

Rationale

• Enable multi-cloud AI provider flexibility without touching agent code.
• Provide a unified interface to swap AI backends (OpenAI, AWS Bedrock, GCP Model Garden/Vertex).
• Reduce duplication and improve maintainability by centralizing provider selection and configuration.

Related issue: closes#3

Summary of Changes

• Core
  • Added src/core/ai.py with get_chat_model() factory supporting:
    • OpenAI (default) via langchain_openai
    • AWS Bedrock via langchain_aws (preferred) or langchain_community fallback
    • GCP Model Garden/Vertex via langchain_google_vertexai
  • Extended AIConfig in src/core/config.py with provider-specific fields:
    • Bedrock: bedrock_region, bedrock_model_id
    • GCP: gcp_project, gcp_location
  • Added validation for provider-specific requirements.
• Agents
  • Replaced direct ChatOpenAI usage with get_chat_model() in:
    • src/agents/base.py
    • src/agents/feasibility_agent/nodes.py
    • src/agents/engine_agent/nodes.py
    • src/agents/acknowledgment_agent/agent.py
• No behavioral changes to agent APIs; only the AI backend instantiation is abstracted.

Behavior Change

• Agents now obtain the chat model via a provider-agnostic factory.
• Switching providers requires only environment variable changes; no code edits.

Configuration

• Env vars:
  • Common:
    • AI_PROVIDER = openai | bedrock | garden
    • AI_MODEL, AI_MAX_TOKENS, AI_TEMPERATURE
  • OpenAI:
    • OPENAI_API_KEY
  • AWS Bedrock:
    • BEDROCK_REGION (optional hint)
    • BEDROCK_MODEL_ID (optional; falls back to AI_MODEL)
    • Credentials resolved via AWS env/IMDS
  • GCP Garden/Vertex:
    • GCP_PROJECT_ID (optional, recommended)
    • GCP_LOCATION (optional, recommended)
    • Authentication via ADC or env credentials

Optional dependencies (to be installed by users selecting these providers):

• Bedrock: langchain-aws (preferred) or langchain-community
• GCP/Vertex: langchain-google-vertexai

Performance

• No change to algorithmic complexity.
• Adheres to performance policy: static → hybrid → LLM. Only instantiation path changed.

Security

• No secrets are logged.
• Credentials are read from environment/standard cloud auth mechanisms.
• No changes to webhook verification or secret handling.

Risk and Rollback

• Risk: Import errors if optional provider deps are missing and AI_PROVIDER is set accordingly.
  • Mitigation: Clear runtime error messages guide installation.
• Rollback plan: Set AI_PROVIDER=openai to use the default path; code remains compatible.

CI

• Types and lint pass locally.
• No changes to CI workflows required.

PR Checklist (per CONTRIBUTING)

• Types added/updated; Pydantic at boundaries unchanged
• Tests green locally (lint/type/tests)
• Performance order respected (static→hybrid→LLM)
• Small, focused edits; no unrelated refactors
• No secrets in logs or prompts
• Docs updated (can be added to this PR if maintainers prefer)

Branch

• feat/ai-wrapper-bedrock-garden

[aryanai-codes]

@dimeloper any update?

[dkargatzis]

@dimeloper any update?

Guess you mentioned wrong GitHub user - btw, I've created a PR on top of your with important additions / fixes. Please have a look and let me know. Also, make you use the same GitHub account, I see your last comment left by a different account.

[aryanraj2713]

Yeah, 😁looks like I mentioned someone else.

[aryanai-codes]

@dkargatzis please let me know if you need any help on this? Or any other issue/feature.
Also I installed warestack for my org's repo, will let you know the experience

[dkargatzis]

Completed the Google application and still awaiting the 20K credits to be topped up in our account. If the credits aren’t in place by tomorrow, I’ll proceed to merge and handle any follow-up PRs as part of the post-merge triage.

Regarding Warestack onboarding - great news! I’m happy to assist you or run a live demo anytime. Your feedback is always welcome as we continue refining the experience.

[dkargatzis]

Hey @aryanraj2713, would you like to take a deeper look into the repo to align the tests? Happy to help out or handle it if it turns out to be too much.

[aryanraj2713]

Sure, do you want to setup a meet?

[dkargatzis]

Sure, do you want to setup a meet?

Sure @aryanraj2713! Feel to book a slot here

[dkargatzis]

@aryanraj2713 I noticed that you haven't created the calendar event - do you want me to handle this?

[aryanraj2713]

Hey sorry, we had festivals here in India and I got busy, will try to schedule ASAP

[dkargatzis]

Cool, looking forward to our meet!

[aryanraj2713]

Link is dead

[dkargatzis]

@aryanraj2713 the link says "A meeting has already been scheduled using this link." - we had a call a few days ago but you didn't join. Here is a new one - feel free to book a new meeting!

https://calendly.com/dimitris-kargatzis/new-meeting