A few notes on how the GUI apps should use the Inform command line.

§1. How the application should install extensions. When the Inform 7 application looks at a file chosen by the user to be installed, it should look at the first line. (Note that this might have any of 0a, 0d, 0a0d, 0d0a, or Unicode line division as its line ending: and that the file might, or might not, begin with a Unicode BOM, "byte order marker", code. Characters within the line will be encoded as UTF-8, though — except possibly for some exotic forms of space — they will all be found in the ISO Latin-1 set.) The first line is required to have one of the following forms, possibly with white space before or after, but definitely without line breaks before:

Locksmith Extra by Emily Short begins here.

Version 2 of Locksmith Extra by Emily Short begins here.

Version 2.7 of Locksmith Extra by Emily Short begins here.

Version 2.1.32 of Locksmith Extra by Emily Short begins here.

Version 2/081121 of Locksmith Extra by Emily Short begins here.

If the name of the extension finishes with a bracketed clause, that should be disregarded. Such clauses are used to specify virtual machine requirements, at present, and could conceivably be used for other purposes later, so let's reserve them now.

Version 2 of Glulx Text Effects (for Glulx only) by Emily Short begins here.

The application should reject (that is, politely refuse to install) any purported extension file whose first line does not conform to the above.

(Note that the inbuild command-line tool can be used to verify that an extension is properly formatted, and extract its identity and version. See the inbuild manual.)

§2. Ignoring any version number given, the Inform application should then store the file in the external extensions area. For instance, 

~/Library/Inform/Extensions/Emily Short/Glulx Text Effects
 (OS X)My Documents\Inform\Extensions\Emily Short\Glulx Text Effects
 (Windows)Note that the file will probably not have the right name initially, and
will need to be renamed as well as moved. (Note the lack of a file
extension.) The subfolders Inform, Extensions and Emily Short must be
created if not already present.
If to install such an extension would result in over-writing an extension
already present at that filename, the user should be given a warning and
asked if he wants to proceed.
However, note that it is not an error to install an extension with
the same name and author as one in the built-in extensions folder. This
does not result in overwriting, since the newly installed version will live
in the external area, not the built-in area.
An extension may be uninstalled simply by deleting the file: but the
application must not allow the user to uninstall any extension from
the built-in area. We must assume that the latter could be on a read-only
disc, or could be part of a cryptographically signed application bundle.

§3. The extension census. The Inform application should run Inform in "census mode" in order to keep extension documentation up to date. Inform should be run in census mode on three occasions:

When inform7 is run in "census mode", it should be run with the command -census. All output from Inform should be ignored, including its return code: ideally, not even a fatal error should provoke a reaction from the application. If the census doesn't work for some file-system reason, never mind — it's not mission-critical.

§4. What happens in census mode. The census has two purposes: first, to create provisional documentation where needed for new and unused extensions; and second, to create the following index files in the external documentation area (not in the external extension area): 

    .../Extensions.html
    .../ExtIndex.html

Documentation for any individual extension is stored at, e.g., 

    .../Extensions/Victoria Saxe-Coburg-Gotha/Werewolves.html

Inform can generate such a file, for an individual extension, in two ways: (a) provisionally, with much less detail, and (b) fully. Whenever it successfully compiles a work using extension X, it rewrites the documentation for X fully, and updates both the two indexing pages.

When Inform runs in -census mode, what it does is to scan for all extensions. If Inform finds a valid extension with no documentation page, it writes a provisional one; and again, it updates both the two indexing pages.

(Inform in fact runs a census on every compilation, as well, so -census runs do nothing "extra" that a normal run of Inform does not also do. On every census, Inform automatically checks for misfiled or broken extensions, and places a descriptive report of what's wrong on the Extensions.html index page — if people move around or edit extensions by hand, they may run into these errors.)