monitor-duplicate
A deny rule by default: it refuses a second live watcher on one subject, or one on work the agent backgrounded itself, and names what to run instead.
What it catches
A second live watcher on one subject, or one on work the agent backgrounded itself.
Why
A watcher is a host tool that runs a command in the background and wakes the agent on each line it prints, and again when it expires. Its subject is what its command reads: a process pattern, a pid, a file, a job, the project lock, a CI run; a command naming none is its own subject. A second watcher while the first is live wakes the agent twice per event; one on a host task capture, or on the process of a command this agent backgrounded, repeats the notice the host already gives. A backgrounded call that watches without end (magus status --watch, tail -f, watch) is judged the same way, and a leased worker is refused one outright, since its waits are its own runs. Re-arming a watcher that expired passes. It cannot tell a process pattern that also matches someone else's run from one matching only the agent's own.
Default and override
By default this rule takes the decision deny. A workspace sets it by name, in its root
magusfile, to deny, advise or off:
magus\guard.builtins({"monitor-duplicate": "advise"})
A loosening takes effect once it is committed; a tightening applies at once.
Seeing it
A verdict names its rule in brackets, which is how you got here:
deny [monitor-duplicate]: ...
A workspace that sets this rule to advise sees advise [monitor-duplicate]: ... instead.
magus describe rule monitor-duplicate prints the same entry at a terminal, and
magus describe rules lists every rule this workspace enforces.
See also
- All rules - what this workspace enforces, deny first
- The guard - how a verdict is reached and wired
- Setting a built-in rule - how a workspace changes this default