CCARF Practice Question

Paper 2 · Question 8

D1 Agentic Architecture & Orchestration · Paper 2

During the monolith-to-microservices refactoring, each extracted service must follow a consistent Java package naming convention (com.company.service.<service-name>). The team notices that subagents sometimes use inconsistent package names like com.company.app.<service-name> or com.company.<service-name>. A team member proposes adding stronger instructions to the system prompt. What is the correct approach?

• A.Add the naming convention to the system prompt with three concrete examples showing the correct pattern
• B.Implement a PostToolUse hook that inspects written files and normalises any package declarations to the correct com.company.service.<service-name> format
• C.Create a separate validation subagent that reviews all written files for naming compliance after each refactoring batch
• D.Use tool_choice to restrict the agent to a custom write_java_file tool that enforces the naming convention in its implementation

Show answer & explanations

Correct answer: B

A: Prompt instructions with examples improve consistency but still have a non-zero failure rate. Package naming is a deterministic rule that must be enforced 100% of the time to avoid broken imports across services.

B: A PostToolUse hook on file write operations can inspect the output and normalise package names deterministically. This provides a 100% enforcement guarantee regardless of what the model generates, which is the correct approach for structural consistency rules.

C: A validation subagent is still probabilistic — it may miss violations. PostToolUse hooks provide deterministic, inline enforcement that catches every violation at the point of file creation.

D: Creating a custom tool wrapper adds unnecessary complexity. PostToolUse hooks on the existing file write tool achieve the same deterministic enforcement without modifying the tool interface.

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