CCARF Practice Question

Paper 2 · Question 3

D1 Agentic Architecture & Orchestration · Paper 2

The team's refactoring pipeline uses a PreToolUse hook to enforce that every new microservice includes a Dockerfile. However, the hook only checks for Dockerfile existence at the moment the create_service tool is called. A developer points out that some services have their Dockerfiles added in a later commit by a different subagent. What is the flaw in this approach?

• A.The hook should use PostToolUse instead of PreToolUse, checking after service creation whether a Dockerfile was added
• B.Gate the deployment or merge tool rather than create_service, checking Dockerfile existence when the service is considered complete.
• C.Run the hook on every single file write and continuously re-check whether a Dockerfile has appeared yet, failing the build until one does.
• D.The PreToolUse hook is correct but needs a timeout to wait for the Dockerfile to appear within a configurable window

Show answer & explanations

Correct answer: B

A: PostToolUse checks after the tool executes but still only at that single point in time. If the Dockerfile is added in a later commit by a different subagent, PostToolUse on create_service will still miss it.

B: Compliance checks should be enforced at the boundary where the precondition must hold — in this case, before deployment or merge. Checking at service creation time is too early when the workflow allows Dockerfiles to be added in subsequent steps. Moving the gate to the deployment or merge boundary ensures all required artefacts are present regardless of which subagent adds them.

C: Running a Dockerfile check on every file write is wasteful and creates unnecessary overhead. The check should happen once at the right boundary (deployment or merge), not continuously during development.

D: Adding a timeout introduces non-deterministic behaviour and race conditions. The correct fix is to move the enforcement gate to the right point in the workflow, not to add polling delays.

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