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capture-filter

A deny rule by default: it refuses a filter over a run capture or log, which cuts the failure block apart, and names what to run instead.

What it catches

A filter over a run capture or log, which cuts the failure block apart.

Why

A failure prints five lines together: the target, the cause, an output ref, the command that reads that ref, and the command to reproduce it. A filter keeps the one line it matched and drops the rest, so grep 'cause:' keeps the symptom and discards the ref that reads the whole log two lines below it. A range print (sed -n '1,200p') is a filter too: it cuts by POSITION, and the block sits wherever the run left it. The better route is an output contract up front, -o jsonl --tee <file>, queried with jq. It denies by default and names magus query output <ref>, which reads the whole log the filter was cutting. A workspace whose readers need such searches sets it to advise. It fires only on a file a filter READS: a host task capture (tasks/<id>.output) or a run log (.magus/logs/<hex>.log). A pattern shaped like one, such as grep 'global\.output' cmd/, is not a capture.

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({"capture-filter": "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 [capture-filter]: ...

A workspace that sets this rule to advise sees advise [capture-filter]: ... instead.

magus describe rule capture-filter prints the same entry at a terminal, and magus describe rules lists every rule this workspace enforces.

See also

guardrulescapture-filterdeny
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Glossary

Workspace

The magus root directory that owns a set of projects and shared config; the unit magus operates over. Workspace in full.

Magusfile

The magusfile.buzz that declares a project's targets (as export funs) and binds its spells. Magusfile in full.

Target

A named operation (build, test, ...) you invoke with magus run <target>; it may compose a spell's tool-native operations and depend on other targets. Target in full.

Op

A single tool-native command a target composes (long form: operation); the middle of the work hierarchy (Spell to Op to Target). Op in full.

Buzz

The language magusfiles are written in (the .buzz engine). Buzz in full.

CI

An ordinary target you compose yourself with ctx.needs; magus does not hardcode its stages. It is the anchor magus affected ci keys off, and ci strips the rw charm. CI in full.

Agent

A model working through an agent host such as Claude Code, Codex, Cursor or OpenCode. magus treats an agent as one more caller of its CLI, MCP tools and console, held to the same checks as a person. Agent in full.

Run

One target executing under one magus invocation, such as magus run test web or magus affected ci. A run keeps its captured output behind an output reference. Every magus run is a run whether or not any job asked for it; see Job for how the two relate. Run in full.

Conventions

Placeholders

Angle brackets mark a value you replace with your own; never type the brackets:

magus run <target>
magus completion <shell>    # e.g. bash, zsh, fish

<target>, <path>, <shell>, <name> and the like are stand-ins, not literal text.