MGS1001: no ci target defined

magus ci (or magus affected ci, magus affected --plan, magus x ci) was asked to run the ci target, but no project in the selected scope declares one.

[MGS1001] no "ci" target defined in the selected project(s); it is the anchor
"magus affected ci" and "magus affected --plan" key off, so this run would do nothing
  see: .../MGS1001.md

Why

ci is an ordinary magusfile target. Magus does not hardcode a CI chain. You compose the gate yourself with magus\needs, ordering the stages your workspace needs (build, test, lint, ...).

It is the one target magus treats as the CI anchor: magus affected ci and magus affected --plan key off it to decide what the affected set should build and gate. Every other target fans out and silently skips projects that don't declare it. That default suits build/test/lint, but for ci it means a workspace with no ci target anywhere would let magus ci exit 0 having run nothing, reporting a green check that checked nothing.

Magus fails fast instead. Both paths enforce the same rule:

• Run time. Magus.RunCI returns this diagnostic before executing anything when the scope has projects but none declare ci. (An empty scope, such as magus affected ci with no changes, stays a legitimate no-op and is left alone.)
• magus doctor. The ci target check fails when no project in the workspace declares ci, surfacing the gap before CI ever runs it.

Resolution

Define a ci target in your magusfile and compose the stages with magus\needs:

export fun ci(ctx: magus\Context, _a: [str]) > void {
    ctx.needs(build, test, lint);
}

Run magus describe targets to see the stages available to compose. The name matches case- and delimiter-insensitively (magus normalizes CI/Ci to ci), so any casing of the declaration is detected.

In a multi-project workspace the target only needs to exist in one project for the anchor to resolve. Declare it wherever you compose the workspace gate.

What this is NOT

• Not a missing-spell error. ci is never a spell op; it lives in the magusfile and composes spell-backed targets via magus\needs. Adding a spell will not satisfy this check.
• Not triggered by an empty affected set. magus affected ci with no changed projects is a real no-op and does not raise MGS1001. The diagnostic fires only when the scope has projects yet none declare ci.

See also

• targets: the anatomy of a magus target.
• spells § Spells vs Targets: why ci is a target, not a spell.
• magus describe targets: lists the stages you can compose into ci.