How is Hal different from chatting with an AI coding agent?

How is Hal different from chatting with an AI coding agent?

Hal is different from chatting with an AI coding agent because it provides a PRD-native workflow around the agent. Instead of one open-ended conversation, Hal emphasizes planning, story conversion, validation, implementation, reports, archive state, and developer review before merge.

Direct chat is useful but loose

Direct agent chat can work well for tiny edits, exploration, or quick questions. It becomes harder to manage when scope grows, because requirements, constraints, review notes, and decisions may live only in the conversation.

Hal makes the workflow explicit

A Hal loop can include commands such as:

hal plan "describe the product change"
hal convert
hal validate
hal run

The point is not that commands alone make work correct. The point is that the developer gets checkpoints before and after implementation.

Hal vs direct prompting

Dimension	Hal	Direct agent chat
Source of truth	PRD, stories, standards, workflow state.	Conversation context.
Scope control	Plan and validate before run.	Scope can expand turn by turn.
Engine role	Codex, Claude Code, or Pi can be implementation engines.	The agent interface is both workflow and engine.
Review	Inspect artifacts and diffs before merge.	Review often depends on chat history and final diff.

Verification rule

Before relying on Hal, inspect the source repository, engine support FAQ, and install guide. Do not assume support for engines beyond what current source documents.