Providers And Agents

DiffPal separates provider selection from CI and code host setup.

Provider Versus Agent

A provider is the configured runtime entry under runtime.providers. It tells DiffPal which review runtime to use and which provider-specific settings belong to that runtime.

An agent is the actual process that performs model-backed review work. For ACP-based providers, the agent is a CLI process that starts an ACP stdio server. For hosted provider types, the runtime talks to the hosted API described by the provider config.

DiffPal sends the review task and validates the response. The provider or agent owns model behavior, account access, provider tools, sandbox behavior, and credentials.

Built-In Provider Type Versus Generic ACP

Built-in provider types encode the known config shape for supported runtimes, such as Codex ACP, Copilot ACP, and OpenCode ACP. They keep common setup predictable and let generated configs use stable provider IDs.

generic_acp is the escape hatch for any CLI that can start an ACP stdio server. DiffPal does not need provider-specific behavior for that path; it only needs the command that starts the ACP-compatible agent.

Use Providers for setup pages and Configuration for the exhaustive config contract.

Authentication Ownership

DiffPal does not create, license, or manage third-party provider accounts. Provider authentication belongs to the provider and to your CI secret management. Install and authenticate the selected provider before the DiffPal review step, keep provider credentials out of untrusted fork jobs, and avoid committing secrets to .config/diffpal/config.yaml.

Platform publishing credentials are separate from provider credentials. A CI job may need both: one credential lets the provider perform review reasoning, and another lets DiffPal publish feedback to GitHub, GitLab, or Azure DevOps.