Bring your coding agent into the Hal loop

What are pluggable agent engines in Hal?

Pluggable agent engines mean Hal treats the coding agent as the implementation engine rather than the whole workflow. This site mentions Codex, Claude Code, and Pi as supported engines, while Hal keeps planning, validation, running, reporting, archiving, and review checkpoints consistent.

What breaks when the agent is the workflow

If your process lives inside one agent tool, switching tools means rebuilding habits: prompts, conventions, review expectations, and handoff steps. The workflow becomes coupled to the model or interface.

Hal separates the loop from the engine. The PRD-driven process stays stable while the configured coding agent does the implementation work.

How Hal handles it

Configure the engine, then run the same planning and execution flow.

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

The developer keeps the same checkpoints: plan, validate, run, inspect.

What the developer gets

• One workflow across supported engines.
• A stable PRD and story format.
• Reviewable output regardless of which agent runs.
• Less process churn when experimenting with tools.

How to review the setup

Check the current Hal configuration, confirm the selected engine is documented in the repo, and run a small loop before handing over a larger feature. Treat engine changes like any other workflow change: test them before trusting them.

What Hal does and does not do

Hal does	Hal does not do
Structures PRD-native coding loops around planning, validation, implementation, reporting, and reviewable state.	Guarantee code quality, passing tests, delivery speed, revenue, rankings, or production readiness.
Helps supported engines work against smaller, reviewable units of work.	Replace developer review, QA, security review, or merge judgment.

Sources and verification

Before adopting this workflow, verify the current Hal source repository, install docs, pricing status, and machine-readable pricing. Check release notes and engine support before relying on Hal in production work.