backends

ACE supports multiple AI coding backends. Set the backend in ace.toml or ace.local.toml with backend = "value". Default: claude.

cli override

Override the configured backend for a single invocation without editing config. Flags are global — they work on any ace subcommand.

$ ace --codex # launch Codex for this session only
$ ace --claude -- --continue # resume with Claude, passing --continue through
$ ace mcp --codex # check MCP against Codex without switching config

custom backends

Schools, users, or projects can register additional backend entries via [[backends]]. A custom backend aliases a built-in (claude, codex) and may override its launch cmd and env. The MCP, instructions file, and linked-folder behavior are inherited from the aliased kind.

# Override env on the built-in claude backend
[[backends]]
name = "claude"
env = { ANTHROPIC_BASE_URL = "https://proxy.example.com" }

# Custom name aliasing claude
[[backends]]
name = "bailer"
kind = "claude"
env = { ANTHROPIC_BASE_URL = "https://bailer.example.com" }

# Wrap the claude binary through a process wrapper
[[backends]]
name = "claude-wrapped"
kind = "claude"
cmd = ["wrapper", "claude"]

Selectable via backend = "bailer" in any config layer or -b bailer on the CLI. Layer order for merging [[backends]] decls is school → user → project → local; later layers may add new entries or partially override earlier ones. A custom backend cannot introduce new behavior beyond its aliased kind — that requires a source change.

linked folders

ACE links school folders into the project's backend directory. skills/ becomes a real directory with per-skill symlinks (driven by skills/include_skills/exclude_skills in ace.toml); the rest are whole-directory symlinks. Not all backends support every folder.

trust modes

Trust modes control backend permission prompts. Set with trust = "auto" or trust = "yolo" in ace.local.toml, or use ace auto / ace yolo.

MCP registration

ACE registers [[mcp]] entries from school.toml into the active backend. All entries are remote HTTP endpoints.

readiness check

ACE verifies the backend is authenticated before launching a session.

quirks