0005: Agent roster is global, not per-repo

• Status: Accepted — shipped
• Date: 2026-08-28 (recorded); shipped OR-132

Context

The agent roster — name, model and effort per actor (implementer, QA, devops engineer, PR describer, ...) — originally lived as an agents block inside each repository's own orion.json, meaning it had to be re-declared every time Orion was adopted into a new repo, and could drift between repos for no reason tied to the repo itself.

Decision

The roster moved to a single global file, ~/.orion/agents.json, shared by every project. orion config agents writes this file directly; per-project agents blocks in orion.json are no longer read.

Consequences

• Who the implementer is and what model/effort it runs on is an operator preference, not a per-checkout one — adopting Orion into a new repo does not require restating the roster.
• Existing per-project agents blocks in orion.json can be deleted; they are inert.
• Any future actor-level setting (model, effort, or similar) defaults to living in this global file unless there is a specific reason the setting must vary per repository.