Section 2 of 6 - How to Build AI Agents

Q&A Resource Library

How to Build AI Agents - A Practitioner's Guide

Once the foundational concepts are clear, the next question is practical: how do you actually build one? This section walks through the five phases of agent development, the architecture decisions that determine reliability, and the integration landscape every lending institution needs to navigate.

Last updated: June 2025
By LendingIQ
10 min read
5 questions in section 2 of 6
Q6

Learning point 1

How do I actually build an AI agent for my lending institution?

Building an AI agent for a lending institution involves five distinct phases: define the agent's scope, design its reasoning and tool architecture, integrate with your data and systems, test and evaluate rigorously, and deploy with monitoring in place. Skipping any of these phases results in agents that either underperform or create operational risk.

Phase 1 - Scope definition is the most important and most often underestimated. You must answer: what exact task does this agent own end-to-end? What are the inputs it receives? What decisions can it make autonomously, and what must it escalate to a human? What are the hard guardrails - things it must never do regardless of input? A well-scoped agent is far more valuable than a broadly scoped one.

Phase 2 - Architecture design covers how the agent reasons (which LLM, what prompt structure, how many reasoning steps), what tools it can use (API calls, document readers, database queries, calculators), and how it orchestrates multi-step workflows. For lending, most agents need tool access to: credit bureau APIs, document parsing libraries, core banking system APIs, and internal policy knowledge bases.

Phase 3 - Integration is where most institutional implementations stall. Your agent must connect to your core banking system (Temenos, Avaloq, Finastra, Mambu, Thought Machine), LOS, and DMS via secure API layers. LendingIQ solves this by providing pre-built integration connectors for common lending infrastructure - Temenos, Avaloq, Finastra, Mambu, Thought Machine, and bureau APIs for Schufa, Experian UK/Ireland, CRIF, and Banque de France FIBEN.

Q7

Learning point 2

What is an agent's reasoning loop and why does it matter for financial use cases?

An agent's reasoning loop is the cycle it goes through repeatedly: observe the current state, reason about what action to take next, take that action, observe the result, and repeat until the goal is achieved. This is also called the ReAct (Reasoning + Acting) pattern. Understanding this loop is essential because it determines how reliably an agent handles complex, multi-step financial tasks.

In a simple chatbot, there is no loop - it reads your input and generates an output in one step. An agent with a reasoning loop can handle tasks like: analyze this loan application, pull bureau data, compare against our credit policy, calculate the eligible loan amount, and draft a sanction recommendation. Each of these is a separate step, and the agent reasons through them sequentially, using the output of each step to inform the next.

For financial use cases, the quality of the reasoning loop determines whether the agent produces reliable, auditable outputs. A well-designed loop includes explicit reasoning traces - the agent thinks through why it is taking each step - which creates an audit trail that compliance teams can review. This is critical for meeting RBI's expectations around explainability in automated credit decisions.

Q8

Learning point 3

What tools and integrations does an AI agent need to function in a lending institution?

An AI agent in a lending institution is only as powerful as the tools it can access. At minimum, a credit underwriting agent needs: document parsing (to read bank statements, tax returns, and financials), bureau API access (Schufa, Experian (UK/Ireland), CRIF (Italy/Austria/CE), Banque de France FIBEN, and pan-European data sources via PSD2 open banking APIs), core banking system read access (to pull existing customer relationships and payment history), and a policy knowledge base (to check eligibility and calculate limits).

Beyond the basics, mature lending agents also need: VAT verification via national tax authority APIs, account information services (AIS) via PSD2-licensed providers (Tink, TrueLayer, Yapily), and employer verification via national social security databases where permitted, OCR and document intelligence layers (for unstructured documents like rental agreements or salary slips), an internal CRM connection (to understand the customer's full relationship with the lender), and a case management or ticketing system to route outputs to human reviewers when needed.

Tool access must be governed carefully in a regulated institution. Each tool call should be logged, permissioned, and auditable. The agent should operate on a principle of least privilege - it should only have access to the data it needs for its specific function, not to the entire banking database.

Integration layerPurposeExamples
Bureau APIsCredit history, fraud checkSchufa, Experian UK/Ireland, CRIF, Banque de France FIBEN, PSD2 data sources
Core banking systemCustomer relationship, payment historyTemenos, Avaloq, Finastra, Mambu, Thought Machine
Document parsingBank statements, tax returns, financialsOCR + LLM extraction layer
VAT / AIS verificationBusiness income and account information verificationNational tax APIs, Tink, TrueLayer, Yapily, social security databases where permitted
Policy knowledge baseEligibility rules, limit calculationRAG over internal policy docs
Case managementHuman-in-the-loop routingLOS, ticketing system
Q9

Learning point 4

What is multi-agent orchestration and when does a bank need it?

Multi-agent orchestration is the coordination of multiple specialized AI agents working together on a complex task - where one agent hands off work to another, they share context, and an orchestrator agent manages the overall workflow. It is the AI equivalent of a cross-functional team: just as a loan sanction involves credit, legal, operations, and risk teams, an AI-powered sanction process involves multiple specialized agents.

A bank needs multi-agent orchestration when a single end-to-end process involves distinct domains of expertise that are too broad for one agent to handle reliably. For example, a home loan sanction involves: a Document Verification Agent, a Credit Analysis Agent, a Legal Vetting Agent, a Valuation Intelligence Agent, and a Sanctioning Agent. Each has specialized knowledge; no single agent can do all five jobs well.

Orchestration can be designed in two ways: pipeline (sequential - Agent A's output becomes Agent B's input) or parallel with aggregation (multiple agents work simultaneously and an orchestrator combines results). For time-sensitive retail lending, parallel orchestration dramatically reduces TAT. For complex corporate lending, sequential orchestration with review gates is often more appropriate.

Q10

Learning point 5

What is the difference between fine-tuning an LLM and using it off-the-shelf?

An off-the-shelf LLM is a pre-trained model used exactly as released by its creator - you write a prompt, the model responds based on its general training. Fine-tuning involves taking that base model and training it further on your own domain-specific data, so it develops a deeper understanding of your terminology, formats, and decision patterns. Both approaches are valid, but for most lending institution use cases, off-the-shelf models with strong prompt engineering and RAG outperform fine-tuned models while being far cheaper and faster to deploy.

Fine-tuning makes sense when you have a very specific, high-volume, narrow task where the base model consistently makes errors that prompt engineering cannot fix, and where you have thousands of labeled examples to train on. For instance, an EU lender processing applications in multiple regional languages (e.g., a pan-European consumer lender handling French, Spanish, Polish, and Italian documents) might fine-tune for European language document understanding.

The risks of fine-tuning in a regulated environment are significant: fine-tuned models can forget general capabilities, they are harder to update when regulations change, they require substantial data governance controls, and they need periodic retraining as your products and policies evolve. The compliance and data management overhead is non-trivial.

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