feat(ledger): write-path stamping — a pulled canon the session then instantiates lands as a hook instance row (#2791, milestone 294 step 5)

The prior-art hook now names the shapes being written (shapes=kind:name —
every definition in the payload, or the one enclosing an Edit found by
walking the file upward) and the server stamps them as instance rows when
the session PULLED a snippet inside PULL_WINDOW that the payload references
by symbol or that the semantic arm scored for this very payload.
classified_by=hook, evidence in reason; never overrides a judgment or a
canonical row, overridable by classify_shapes. Offered-but-unopened stamps
nothing. Pulled-and-already-seen snippets stay in the semantic query as
evidence without re-entering the deduped menu. A brand-new shape gets a
provisional row the next sync confirms or vanishes. Read-scoped keys get
the hint, never the stamp. Plugin 0.1.34.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

plugin/hooks/scribe_prior_art.sh

@@ -14,6 +14,12 @@
 # on an instance with no forge connection (decision #2707). Everything else is
 # the REUSE menu. The two dedup separately (see the state files below).
 #
+# It is also the shape ledger's write-path feed (#2791): it names the
+# definitions being written (`shapes=`), and the server — only when the
+# session has PULLED a snippet this code references or resembles — records
+# them as instance rows, classified_by=hook. Evidence, not judgment; the
+# context line says what landed so a wrong stamp is corrected in the moment.
+#
 # NEVER BLOCKS. It returns `additionalContext` with no `permissionDecision`, so
 # the write proceeds untouched and Claude sees the note beside the tool result.
 # Any failure — unconfigured, unreachable, malformed — exits 0 in silence. A
@@ -96,10 +102,14 @@ fi
 # `ReturnType name(...)`) needs a real parser, and `impl` blocks are excluded
 # because several per type is normal Rust, not duplication.
 # ---------------------------------------------------------------------------
-local_lines=""
-if [ -n "$repo_root" ] && [ -n "$code" ]; then
-  # kind<TAB>name for each thing this payload DEFINES.
-  names=$(printf '%s' "$code" | awk '
+# kind<TAB>name for each thing a piece of code DEFINES, in source order. One
+# program, two consumers: the local duplicate arm (every definition in the
+# payload) and the ledger feed (#2791, below: the definitions being written,
+# or the one enclosing an Edit). Rule-for-rule mirrored by the server's
+# services/coverage.py extract_shapes — ledger rows are keyed by what THAT
+# sees, so the two must agree on what counts as a definition.
+scribe_defs() {
+  awk '
     {
       # CSS class definition: .name { or .name,
       if (match($0, /^[[:space:]]*\.[A-Za-z][A-Za-z0-9_-]*[[:space:]]*[,{]/)) {
@@ -132,8 +142,16 @@ if [ -n "$repo_root" ] && [ -n "$code" ]; then
         if (t != "") print "sym\t" t; next
       }
     }
-  ' 2>/dev/null | sort -u | head -12) || names=""
+  ' 2>/dev/null
+}
 
+names=""
+if [ -n "$code" ]; then
+  names=$(printf '%s' "$code" | scribe_defs | sort -u | head -12) || names=""
+fi
+
+local_lines=""
+if [ -n "$repo_root" ] && [ -n "$names" ]; then
   while IFS=$'\t' read -r kind name; do
     [ -n "${name:-}" ] || continue
     case "$kind" in
@@ -156,6 +174,38 @@ if [ -n "$local_lines" ]; then
   local_context="> Already defined elsewhere in this repo — check before adding another copy (\`git grep\` shown; this is a nudge, not a gate):"$'\n'"${local_lines}"
 fi
 
+# ---------------------------------------------------------------------------
+# THE LEDGER FEED (#2791). The server keeps a shape ledger — every definition
+# in the bound repo, classified against recorded canon — and this hook is the
+# one place that sees a shape AT THE MOMENT IT IS WRITTEN. So it names the
+# shapes in play: every definition in the payload, or — for an Edit that
+# changes the inside of a function rather than its signature — the definition
+# enclosing the edit, found by walking the target file upward from the edited
+# lines. The server decides whether evidence exists (the session pulled a
+# snippet this code references or resembles) and stamps instance rows; with
+# no pulled canon in play, nothing is recorded. Titles only still — this sends
+# names, not bodies.
+# ---------------------------------------------------------------------------
+shapes="$names"
+if [ -z "$shapes" ] && [ -f "$file_path" ] && command -v tac >/dev/null 2>&1; then
+  old_first=$(printf '%s' "$event" \
+    | jq -r '.tool_input.old_string // .tool_input.old_str // empty' 2>/dev/null \
+    | grep -m1 -v '^[[:space:]]*$') || old_first=""
+  if [ -n "$old_first" ]; then
+    ln=$(grep -nF -m1 -- "$old_first" "$file_path" 2>/dev/null | cut -d: -f1) || ln=""
+    if [ -n "$ln" ]; then
+      shapes=$(head -n "$ln" "$file_path" | tac | scribe_defs | head -1) || shapes=""
+    fi
+  fi
+fi
+shapes_q=""
+if [ -n "$shapes" ]; then
+  enc=$(printf '%s\n' "$shapes" \
+    | awk -F'\t' 'NF>=2 {printf "%s%s:%s", (n++?",":""), $1, $2}' \
+    | jq -sRr '@uri' 2>/dev/null) || enc=""
+  [ -n "$enc" ] && shapes_q="&shapes=${enc}"
+fi
+
 url=${SCRIBE_URL:-${CLAUDE_PLUGIN_OPTION_API_ENDPOINT:-}}
 token=${SCRIBE_TOKEN:-${CLAUDE_PLUGIN_OPTION_API_TOKEN:-}}
 # Guard against an unexpanded ${...} placeholder arriving as a literal.
@@ -230,7 +280,7 @@ fi
 # finding that needed no instance to produce.
 body=$(curl -fsS --max-time 5 \
   -H "Authorization: Bearer ${token}" \
-  "${url%/}/api/plugin/prior-art?path=${path_enc}&code=${code_enc}${repo_q}${exclude_q}${sync_exclude_q}" 2>/dev/null) || body=""
+  "${url%/}/api/plugin/prior-art?path=${path_enc}&code=${code_enc}${repo_q}${exclude_q}${sync_exclude_q}${shapes_q}" 2>/dev/null) || body=""
 
 context=""
 if [ -n "$body" ]; then