diff --git a/.gitignore b/.gitignore
index b959e80..7556fab 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@
 *.2mg 
 *.po
 # merlin assembly listings
-*_output.txt
\ No newline at end of file
+*_output.txt
+*.exe
\ No newline at end of file
diff --git a/README.md b/README.md
index e0a6a94..a001067 100644
--- a/README.md
+++ b/README.md
@@ -27,10 +27,13 @@ Appy abstracts the tools away from a script mindset, and into a project mindset.
 
 ## The project file
 
-Currently it uses an `appy.yaml` file in the current project directory. The format is as follows:
+Appy uses an `appy.yaml` file in the current project directory. The basic format is as follows:
 ```
 assemble: [main.s, grafix.s, snd.s, a.s, b.s]   # <--- list of files to assemble with Merlin   
-indent: [c.s]                                   # <--- additional files to indent when running `appy fmt`               
+assembleflags: "-V"                             # <--- optional flags to Merlin, including macro directory
+indent: [c.s]                                   # <--- optional additional files to indent when running `appy fmt` 
+formatflags: "mc:10 oc:14 cc:30 ms:1 bs:2"      # <--- optional flags to indent 
+
 disks:                                          # <--- define disks, can be more than one, handy for 140K + 800K
 - name: mydiskimage                             #   <---- each disk has a name (ProDOS volume name)
   file: mydiskimage800.2mg                      #   <---- each disk has a filename for the image it creates
@@ -78,6 +81,34 @@ $ appy fmt          # format/indent your assembly file in appy.yaml
                     # you can also pass in filename(s) to format
 ```
 
+### About the built-in code formatter
+
+Appy uses the [MerlinGo](https://github.com/digarok/merlingo) formatter to indent source code.  You can override the default indentation with the various options documented here.
+
+- `mc`: mnemonic column, where instructions start
+- `oc`: opcode column
+- `cc`: comment column
+- `ms`: min space, the minimum amount of space it will allow between two columns
+
+You can define these in your `appy.yaml` project file like so:
+```
+formatflags: "mc:10 oc:14 cc:30 ms:1" 
+```
+
+You can also set it in files directly by adding it as a comment marked `ed:` on any line of the file like:
+``` 
+*  ed: mc=40 oc=26 cc=48 ms=5   <-  indentation modeline
+```
+ OR
+```
+        org $2000
+                ;  ed: mc=40 oc=26 cc=48 ms=5   <-  indentation modeline
+        lda ...         
+```
+Again either comment style works on any line of the file, but don't add more than one modeline per file. 
+
+Also, if you set format options at the project AND file level, then Appy will use the project defaults except when a file specifies its own settings, then it will respect the file settings instead. 
+
 ### Version Notes
 This is an early experimental version not intended for public use.
 
diff --git a/appy.yaml b/appy.yaml
index f3f8f6c..51f16ee 100644
--- a/appy.yaml
+++ b/appy.yaml
@@ -1,5 +1,6 @@
 assemble: [testsrc/sp.s, testsrc/pc.s, testsrc/fmt.s]
 assembleflags: "-V"
+formatflags: "mc:10 oc:14 cc:30 ms:1 bs:2"
 indent: [testsrc/fmt2.s]
 disks:
 - name: mydiskimage
diff --git a/core/formatter.go b/core/formatter.go
index bc18ee9..93af187 100644
--- a/core/formatter.go
+++ b/core/formatter.go
@@ -8,6 +8,10 @@ import (
 )
 
 func Format(args []string) {
+	// merlingo.Status()
+	if project.AppyProj.FormatFlags != "" {
+		merlingo.ParseModeline(project.AppyProj.FormatFlags)
+	}
 	if len(args) == 0 {
 		// format all assembly files in appy.yaml
 		for _, filename := range project.AppyProj.Assemble {
@@ -26,4 +30,5 @@ func Format(args []string) {
 			merlingo.FmtFile(filename)
 		}
 	}
+	// merlingo.Status()
 }
diff --git a/core/project/project.go b/core/project/project.go
index fab1ebf..2921fb6 100644
--- a/core/project/project.go
+++ b/core/project/project.go
@@ -15,6 +15,7 @@ type Project struct {
 	Assemble      []string
 	Indent        []string
 	AssembleFlags string
+	FormatFlags   string
 }
 
 type Disk struct {
diff --git a/go.mod b/go.mod
index cd4fe97..a642e57 100644
--- a/go.mod
+++ b/go.mod
@@ -3,7 +3,7 @@ module github.com/digarok/appy
 go 1.16
 
 require (
-	github.com/digarok/merlingo v1.0.3
+	github.com/digarok/merlingo v1.0.4
 	github.com/fatih/color v1.13.0
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/spf13/cobra v1.1.3
diff --git a/go.sum b/go.sum
index 93f5dbd..d17eb0f 100644
--- a/go.sum
+++ b/go.sum
@@ -39,6 +39,8 @@ github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZm
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
 github.com/digarok/merlingo v1.0.3 h1:W0jtn8PZQsBlkpvfODFO38GSFx91uV4LXDhN1dkK62A=
 github.com/digarok/merlingo v1.0.3/go.mod h1:rdReR6enl/63dfkssdM4xwg0gXw3j4QprK9e+e8mX9U=
+github.com/digarok/merlingo v1.0.4 h1:9OMF44OFas04cKGh9qql56IvOGrWjjbgri+n8LqLd88=
+github.com/digarok/merlingo v1.0.4/go.mod h1:rdReR6enl/63dfkssdM4xwg0gXw3j4QprK9e+e8mX9U=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/color v1.13.0 h1:8LOYc1KYPPmyKMuN8QV2DNRWNbLo6LZ0iLs8+mlH53w=
 github.com/fatih/color v1.13.0/go.mod h1:kLAiJbzzSOZDVNGyDpeOxJ47H46qBXwg5ILebYFFOfk=
diff --git a/testsrc/fmt2.s b/testsrc/fmt2.s
index 70a02af..f7d68cb 100644
--- a/testsrc/fmt2.s
+++ b/testsrc/fmt2.s
@@ -25,3 +25,4 @@ ReallyThisisaLoooooongLabelwith stal $e12000,y  ; look at this long line
 
 * TABS....
 * $D5	$0008	 sequence [Application Specific]
+                                                ;  ed: mc=40 oc=26 cc=48 ms=5 bs=2   <-  indentation modeline