diff --git a/bin/ci_browser_foundation.grease b/bin/ci_browser_foundation.grease
index b37fa92..b8867e6 100755
--- a/bin/ci_browser_foundation.grease
+++ b/bin/ci_browser_foundation.grease
@@ -19,13 +19,13 @@ build_idric() {
   git -C /tmp/Idric checkout --detach -q FETCH_HEAD
   test "$(git -C /tmp/Idric rev-parse HEAD)" = "$idric_ref"
 
-  idric_build_root=/tmp/Idric
-  if [ -f /tmp/Idric/_/Makefile ]; then
-    idric_build_root=/tmp/Idric/_
-  fi
-
-  SCHEME=chezscheme make -C "$idric_build_root" bootstrap PREFIX="$idric_prefix"
-  SCHEME=chezscheme make -C "$idric_build_root" install PREFIX="$idric_prefix"
+  # Current Edric owns its bootstrap/build machinery below _/.  Use the stable
+  # top-level entrypoint rather than depending on the old root Makefile layout.
+  PREFIX="$idric_prefix" sh /tmp/Idric/edric bootstrap
+  make -C /tmp/Idric/_ install \
+    PREFIX="$idric_prefix" \
+    SCHEME=/tmp/Idric/_/.tools/bin/scheme
+  test -x "$idric_prefix/bin/idris2"
 }
 
 verify_pdf_harvester() {
diff --git a/src/CanonicalInformationSmoke.idric b/src/CanonicalInformationSmoke.idric
index e97a82b..15ce11f 100644
--- a/src/CanonicalInformationSmoke.idric
+++ b/src/CanonicalInformationSmoke.idric
@@ -1,35 +1,38 @@
 module CanonicalInformationSmoke
 
-import IB.Information.Model
-import IB.Prepaint.Model
+import IB.Strand
+import IB.Prepaint
 import IB.Prepaint.Version1
 
 %default total
 
 fixture_strand : Maybe Strand
 fixture_strand = do
-  source_reference <- nonempty_text "fixture:strand-1"
-  requested <- requested_address "https://example.test/requested"
-  resolved <- resolved_address "https://example.test/resolved"
-  image <- fetched_image "asset:figure-1"
-  let source = Source source_reference HtmlRepresentation CompleteRepresentation
+  source_reference ← nonempty_text "fixture:strand-1"
+  requested ← requested_address "https://example.test/requested"
+  resolved ← resolved_address "https://example.test/resolved"
+  image ← image_reference "asset:figure-1"
+  next_link ← link_reference "/next"
+  search_form ← form_reference "/search"
+  figure_link ← link_reference "/figure/1"
+  let source = Source source_reference HtmlSource CompleteSource
   pure
     (MakeStrand
       source
       requested
       resolved
       (Just "Example")
-      [ InformationHeading Heading2 "Section"
-      , InformationText "Visible paragraph"
-      , InformationLink "Next" (LinkReference "/next")
-      , InformationTableRow (TableCells "first" ["second"])
-      , InformationForm "Search" (FormReference "/search")
-      , InformationImage image "diagram" "Figure 1" (Just (LinkReference "/figure/1"))
+      [ Heading Heading2 "Section"
+      , Text "Visible paragraph"
+      , Link "Next" next_link
+      , TableRow (table_row "first" ["second"])
+      , Form "Search" search_form
+      , Image image "diagram" "Figure 1" (Just figure_link)
       ])
 
 empty_image_refused : Bool
 empty_image_refused =
-  case fetched_image "" of
+  case image_reference "" of
     Nothing ⇒ True
     Just _ ⇒ False
 
@@ -41,8 +44,8 @@ seventh_heading_refused =
 
 nonincreasing_revision_refused : Strand → Bool
 nonincreasing_revision_refused strand =
-  let first = revision_from_strand (Revision 1) PartialRevision strand in
-  let second = revision_from_strand (Revision 1) CompleteRevision strand in
+  let first = prepaint_from_strand first_revision PartialRevision strand in
+  let second = prepaint_from_strand first_revision CompleteRevision strand in
   case serialize_version1 [first, second] of
     Nothing ⇒ True
     Just _ ⇒ False
@@ -55,12 +58,12 @@ version1_result (Just version1_text) =
 
 strand_report : Strand → String
 strand_report strand =
-  let partial = revision_from_strand (Revision 0) PartialRevision strand in
-  let complete = revision_from_strand (Revision 1) CompleteRevision strand in
+  let partial = prepaint_from_strand first_revision PartialRevision strand in
+  let complete = prepaint_from_strand (next_revision first_revision) CompleteRevision strand in
   unlines
     [ "canonical-information=constructed"
     , "canonical-blocks=" ++ show (length strand.blocks)
-    , "canonical-row-cells=" ++ show (length (table_row_cells (TableCells "first" ["second"])))
+    , "canonical-row-cells=" ++ show (length (table_row_cells (table_row "first" ["second"])))
     , "empty-image-refused=" ++ show empty_image_refused
     , "seventh-heading-refused=" ++ show seventh_heading_refused
     , "revision-zero=" ++ show (revision_sequence_value partial.sequence)
diff --git a/src/IB/Information/Model.idric b/src/IB/Information/Model.idric
deleted file mode 100644
index 383cd2b..0000000
--- a/src/IB/Information/Model.idric
+++ /dev/null
@@ -1,137 +0,0 @@
-module IB.Information.Model
-
-%default total
-
-public export
-data NonemptyText = TextBeginning Char (List Char)
-
-public export
-nonempty_text : String → Maybe NonemptyText
-nonempty_text value =
-  case unpack value of
-    [] => Nothing
-    first :: rest => Just (TextBeginning first rest)
-
-public export
-nonempty_text_value : NonemptyText → String
-nonempty_text_value (TextBeginning first rest) = pack (first :: rest)
-
-public export
-data RepresentationOrigin
-  = HtmlRepresentation
-  | PdfRepresentation
-  | PlainTextRepresentation
-  | DerivedRepresentation
-  | OtherRepresentation
-
-public export
-data RepresentationCompleteness
-  = PartialRepresentation
-  | CompleteRepresentation
-
-public export
-record SourceRepresentation where
-  constructor Source
-  reference : NonemptyText
-  origin : RepresentationOrigin
-  completeness : RepresentationCompleteness
-
-public export
-data RequestedAddressText = RequestedAddress NonemptyText
-
-public export
-data ResolvedAddressText = ResolvedAddress NonemptyText
-
-public export
-data LinkReferenceText = LinkReference String
-
-public export
-data FormReferenceText = FormReference String
-
-public export
-data FetchedImageReference = FetchedImage NonemptyText
-
-public export
-requested_address : String → Maybe RequestedAddressText
-requested_address value = map RequestedAddress (nonempty_text value)
-
-public export
-resolved_address : String → Maybe ResolvedAddressText
-resolved_address value = map ResolvedAddress (nonempty_text value)
-
-public export
-fetched_image : String → Maybe FetchedImageReference
-fetched_image value = map FetchedImage (nonempty_text value)
-
-public export
-requested_address_value : RequestedAddressText → String
-requested_address_value (RequestedAddress value) = nonempty_text_value value
-
-public export
-resolved_address_value : ResolvedAddressText → String
-resolved_address_value (ResolvedAddress value) = nonempty_text_value value
-
-public export
-link_reference_value : LinkReferenceText → String
-link_reference_value (LinkReference value) = value
-
-public export
-form_reference_value : FormReferenceText → String
-form_reference_value (FormReference value) = value
-
-public export
-fetched_image_value : FetchedImageReference → String
-fetched_image_value (FetchedImage value) = nonempty_text_value value
-
-public export
-data HeadingLevel
-  = Heading1
-  | Heading2
-  | Heading3
-  | Heading4
-  | Heading5
-  | Heading6
-
-public export
-heading_level_number : HeadingLevel → Nat
-heading_level_number Heading1 = 1
-heading_level_number Heading2 = 2
-heading_level_number Heading3 = 3
-heading_level_number Heading4 = 4
-heading_level_number Heading5 = 5
-heading_level_number Heading6 = 6
-
-public export
-heading_level : Nat → Maybe HeadingLevel
-heading_level 1 = Just Heading1
-heading_level 2 = Just Heading2
-heading_level 3 = Just Heading3
-heading_level 4 = Just Heading4
-heading_level 5 = Just Heading5
-heading_level 6 = Just Heading6
-heading_level _ = Nothing
-
-public export
-data NonemptyTableRow = TableCells String (List String)
-
-public export
-table_row_cells : NonemptyTableRow → List String
-table_row_cells (TableCells first rest) = first :: rest
-
-public export
-data InformationBlock
-  = InformationHeading HeadingLevel String
-  | InformationText String
-  | InformationLink String LinkReferenceText
-  | InformationTableRow NonemptyTableRow
-  | InformationForm String FormReferenceText
-  | InformationImage FetchedImageReference String String (Maybe LinkReferenceText)
-
-public export
-record Strand where
-  constructor MakeStrand
-  source : SourceRepresentation
-  requested : RequestedAddressText
-  resolved : ResolvedAddressText
-  title : Maybe String
-  blocks : List InformationBlock
diff --git a/src/IB/Prepaint.idric b/src/IB/Prepaint.idric
new file mode 100644
index 0000000..b3d124f
--- /dev/null
+++ b/src/IB/Prepaint.idric
@@ -0,0 +1,51 @@
+module IB.Prepaint
+
+import IB.Strand
+
+%default total
+
+-- Revision numbers are generated here rather than exposed as an unrestricted
+-- machine count.  Zero is the first valid revision and next_revision is the
+-- only public way to advance it.
+export
+data RevisionSequence = Revision Integer
+
+export
+first_revision : RevisionSequence
+first_revision = Revision 0
+
+export
+next_revision : RevisionSequence → RevisionSequence
+next_revision (Revision value) = Revision (value + 1)
+
+export
+revision_sequence_value : RevisionSequence → Integer
+revision_sequence_value (Revision value) = value
+
+public export
+data RevisionState
+  = PartialRevision
+  | CompleteRevision
+
+public export
+record PrepaintRevision where
+  constructor Prepaint
+  sequence : RevisionSequence
+  state : RevisionState
+  source : SourceRepresentation
+  requested : RequestedAddress
+  resolved : ResolvedAddress
+  title : Maybe String
+  blocks : List InformationBlock
+
+export
+prepaint_from_strand : RevisionSequence → RevisionState → Strand → PrepaintRevision
+prepaint_from_strand sequence state strand =
+  Prepaint
+    sequence
+    state
+    strand.source
+    strand.requested
+    strand.resolved
+    strand.title
+    strand.blocks
diff --git a/src/IB/Prepaint/Model.idric b/src/IB/Prepaint/Model.idric
deleted file mode 100644
index d94f0f2..0000000
--- a/src/IB/Prepaint/Model.idric
+++ /dev/null
@@ -1,40 +0,0 @@
-module IB.Prepaint.Model
-
-import IB.Information.Model
-
-%default total
-
-public export
-data RevisionSequence = Revision Nat
-
-public export
-revision_sequence_value : RevisionSequence → Nat
-revision_sequence_value (Revision value) = value
-
-public export
-data RevisionState
-  = PartialRevision
-  | CompleteRevision
-
-public export
-record PrepaintRevision where
-  constructor Prepaint
-  sequence : RevisionSequence
-  state : RevisionState
-  source : SourceRepresentation
-  requested : RequestedAddressText
-  resolved : ResolvedAddressText
-  title : Maybe String
-  blocks : List InformationBlock
-
-public export
-revision_from_strand : RevisionSequence → RevisionState → Strand → PrepaintRevision
-revision_from_strand sequence state strand =
-  Prepaint
-    sequence
-    state
-    strand.source
-    strand.requested
-    strand.resolved
-    strand.title
-    strand.blocks
diff --git a/src/IB/Prepaint/Version1.idric b/src/IB/Prepaint/Version1.idric
index 90fc839..91bf801 100644
--- a/src/IB/Prepaint/Version1.idric
+++ b/src/IB/Prepaint/Version1.idric
@@ -1,7 +1,7 @@
 module IB.Prepaint.Version1
 
-import IB.Information.Model
-import IB.Prepaint.Model
+import IB.Strand
+import IB.Prepaint
 
 %default total
 
@@ -25,12 +25,7 @@ join_fields [value] = value
 join_fields (value :: rest) = value ++ "\t" ++ join_fields rest
 
 heading_level_text : HeadingLevel → String
-heading_level_text Heading1 = "1"
-heading_level_text Heading2 = "2"
-heading_level_text Heading3 = "3"
-heading_level_text Heading4 = "4"
-heading_level_text Heading5 = "5"
-heading_level_text Heading6 = "6"
+heading_level_text level = show (heading_level_number level)
 
 revision_state_text : RevisionState → String
 revision_state_text PartialRevision = "partial"
@@ -41,33 +36,33 @@ maybe_text Nothing = ""
 maybe_text (Just value) = value
 
 serialize_block : InformationBlock → String
-serialize_block (InformationHeading level text) =
+serialize_block (Heading level text) =
   join_fields ["heading", heading_level_text level, escape_field text]
-serialize_block (InformationText text) =
+serialize_block (Text text) =
   join_fields ["text", escape_field text]
-serialize_block (InformationLink text reference) =
+serialize_block (Link text reference) =
   join_fields ["link", escape_field text, escape_field (link_reference_value reference)]
-serialize_block (InformationTableRow row) =
+serialize_block (TableRow row) =
   join_fields ("row" :: map escape_field (table_row_cells row))
-serialize_block (InformationForm text reference) =
+serialize_block (Form text reference) =
   join_fields ["form", escape_field text, escape_field (form_reference_value reference)]
-serialize_block (InformationImage source alternate caption Nothing) =
+serialize_block (Image source alternate caption Nothing) =
   join_fields
     [ "image"
-    , escape_field (fetched_image_value source)
+    , escape_field (image_reference_value source)
     , escape_field alternate
     , escape_field caption
     ]
-serialize_block (InformationImage source alternate caption (Just reference)) =
+serialize_block (Image source alternate caption (Just reference)) =
   join_fields
     [ "image"
-    , escape_field (fetched_image_value source)
+    , escape_field (image_reference_value source)
     , escape_field alternate
     , escape_field caption
     , escape_field (link_reference_value reference)
     ]
 
-public export
+export
 serialize_revision : PrepaintRevision → List String
 serialize_revision revision =
   join_fields
@@ -80,18 +75,19 @@ serialize_revision revision =
   join_fields ["title", escape_field (maybe_text revision.title)] ::
   map serialize_block revision.blocks ++ ["end"]
 
-strictly_after : Nat → PrepaintRevision → Bool
-strictly_after previous revision = previous < revision_sequence_value revision.sequence
+strictly_after : RevisionSequence → PrepaintRevision → Bool
+strictly_after previous revision =
+  revision_sequence_value previous < revision_sequence_value revision.sequence
 
-serialize_revisions : Maybe Nat → List PrepaintRevision → Maybe (List String)
+serialize_revisions : Maybe RevisionSequence → List PrepaintRevision → Maybe (List String)
 serialize_revisions previous [] = Just []
 serialize_revisions Nothing (revision :: rest) = do
-  remaining <- serialize_revisions (Just (revision_sequence_value revision.sequence)) rest
+  remaining ← serialize_revisions (Just revision.sequence) rest
   pure (serialize_revision revision ++ remaining)
 serialize_revisions (Just previous) (revision :: rest) =
   if strictly_after previous revision
     then do
-      remaining <- serialize_revisions (Just (revision_sequence_value revision.sequence)) rest
+      remaining ← serialize_revisions (Just revision.sequence) rest
       pure (serialize_revision revision ++ remaining)
     else Nothing
 
@@ -99,8 +95,8 @@ join_lines : List String → String
 join_lines [] = ""
 join_lines (line :: rest) = line ++ "\n" ++ join_lines rest
 
-public export
+export
 serialize_version1 : List PrepaintRevision → Maybe String
 serialize_version1 revisions = do
-  body <- serialize_revisions Nothing revisions
+  body ← serialize_revisions Nothing revisions
   pure (join_lines (join_fields ["ib-prepaint", "1"] :: body))
diff --git a/src/IB/Strand.idric b/src/IB/Strand.idric
new file mode 100644
index 0000000..2fe7617
--- /dev/null
+++ b/src/IB/Strand.idric
@@ -0,0 +1,151 @@
+module IB.Strand
+
+%default total
+
+-- These wrappers keep empty filesystem, source, address, and resource names out
+-- of the semantic strand.  Their representations stay private to this module.
+export
+data NonemptyText = TextBeginning Char (List Char)
+
+export
+nonempty_text : String → Maybe NonemptyText
+nonempty_text value =
+  case unpack value of
+    [] ⇒ Nothing
+    first :: rest ⇒ Just (TextBeginning first rest)
+
+export
+nonempty_text_value : NonemptyText → String
+nonempty_text_value (TextBeginning first rest) = pack (first :: rest)
+
+public export
+data RepresentationOrigin
+  = HtmlSource
+  | PdfSource
+  | PlainTextSource
+  | DerivedSource
+  | OtherSource
+
+public export
+data RepresentationCompleteness
+  = PartialSource
+  | CompleteSource
+
+public export
+record SourceRepresentation where
+  constructor Source
+  reference : NonemptyText
+  origin : RepresentationOrigin
+  completeness : RepresentationCompleteness
+
+export
+data RequestedAddress = Requested NonemptyText
+
+export
+data ResolvedAddress = Resolved NonemptyText
+
+export
+data LinkReference = LinkTo NonemptyText
+
+export
+data FormReference = SubmitTo NonemptyText
+
+export
+data ImageReference = ImageAt NonemptyText
+
+export
+requested_address : String → Maybe RequestedAddress
+requested_address value = map Requested (nonempty_text value)
+
+export
+resolved_address : String → Maybe ResolvedAddress
+resolved_address value = map Resolved (nonempty_text value)
+
+export
+link_reference : String → Maybe LinkReference
+link_reference value = map LinkTo (nonempty_text value)
+
+export
+form_reference : String → Maybe FormReference
+form_reference value = map SubmitTo (nonempty_text value)
+
+export
+image_reference : String → Maybe ImageReference
+image_reference value = map ImageAt (nonempty_text value)
+
+export
+requested_address_value : RequestedAddress → String
+requested_address_value (Requested value) = nonempty_text_value value
+
+export
+resolved_address_value : ResolvedAddress → String
+resolved_address_value (Resolved value) = nonempty_text_value value
+
+export
+link_reference_value : LinkReference → String
+link_reference_value (LinkTo value) = nonempty_text_value value
+
+export
+form_reference_value : FormReference → String
+form_reference_value (SubmitTo value) = nonempty_text_value value
+
+export
+image_reference_value : ImageReference → String
+image_reference_value (ImageAt value) = nonempty_text_value value
+
+public export
+data HeadingLevel
+  = Heading1
+  | Heading2
+  | Heading3
+  | Heading4
+  | Heading5
+  | Heading6
+
+export
+heading_level_number : HeadingLevel → Integer
+heading_level_number Heading1 = 1
+heading_level_number Heading2 = 2
+heading_level_number Heading3 = 3
+heading_level_number Heading4 = 4
+heading_level_number Heading5 = 5
+heading_level_number Heading6 = 6
+
+export
+heading_level : Integer → Maybe HeadingLevel
+heading_level 1 = Just Heading1
+heading_level 2 = Just Heading2
+heading_level 3 = Just Heading3
+heading_level 4 = Just Heading4
+heading_level 5 = Just Heading5
+heading_level 6 = Just Heading6
+heading_level _ = Nothing
+
+export
+data NonemptyTableRow = TableCells String (List String)
+
+export
+table_row : String → List String → NonemptyTableRow
+table_row first remaining = TableCells first remaining
+
+export
+table_row_cells : NonemptyTableRow → List String
+table_row_cells (TableCells first remaining) = first :: remaining
+
+public export
+data InformationBlock
+  = Heading HeadingLevel String
+  | Text String
+  | Link String LinkReference
+  | TableRow NonemptyTableRow
+  | Form String FormReference
+  | Image ImageReference String String (Maybe LinkReference)
+
+public export
+record Strand where
+  constructor MakeStrand
+  source : SourceRepresentation
+  requested : RequestedAddress
+  resolved : ResolvedAddress
+  title : Maybe String
+  blocks : List InformationBlock