fix(compaction): scope legacy checkpoint recognition by era

crates/tui/src/compaction.rs

@@ -512,6 +512,36 @@ pub(crate) fn is_compaction_checkpoint_message(message: &Message) -> bool {
         || user_text_of(message).is_some_and(|text| is_legacy_compaction_summary_text(&text))
 }
 
+/// Whether this history already carries a provenance-stamped checkpoint.
+///
+/// A stamped carrier postdates stamping, so within that history only the
+/// stamped form is a checkpoint: a user turn whose text merely starts with a
+/// legacy summary header (a pasted transcript, for example) is content. A
+/// history without one predates the stamp — there the pasted header is
+/// indistinguishable from the saved bare carrier, so the loose form keeps
+/// applying. The signal is the history's content, not the session's age: it
+/// is one-way and destructible (`/edit` or a host rewind can truncate away
+/// the only stamped carrier), and typed input cannot forge the two-block
+/// form.
+#[must_use]
+pub(crate) fn history_is_post_provenance(messages: &[Message]) -> bool {
+    messages.iter().any(is_wire_compaction_checkpoint_message)
+}
+
+/// Era-aware checkpoint recognition for the recompaction family: the loose
+/// legacy fallback applies only in a history with no stamped carrier.
+#[must_use]
+pub(crate) fn is_compaction_checkpoint_message_in_era(
+    message: &Message,
+    post_provenance: bool,
+) -> bool {
+    if post_provenance {
+        is_wire_compaction_checkpoint_message(message)
+    } else {
+        is_compaction_checkpoint_message(message)
+    }
+}
+
 /// Request-time recognition: exactly the header text block plus the
 /// provenance block. User text merely quoting a marker keeps its original
 /// wire position. Checkpoints saved before the handoff note still pass, so
@@ -1540,7 +1570,23 @@ fn is_orphaned_result_block(block: &ContentBlock) -> bool {
     )
 }
 
+/// Test convenience: derive the era from the slice itself. Production
+/// callers pass [`retained_user_messages_in_era`] the era of the history the
+/// slice belongs to — retention runs on the pre-round prefix, whose carrier
+/// may sit inside the round.
+#[cfg(test)]
 pub(crate) fn retained_user_messages(messages: &[Message], max_tokens: usize) -> Vec<Message> {
+    retained_user_messages_in_era(history_is_post_provenance(messages), messages, max_tokens)
+}
+
+/// `post_provenance` must be derived from the history the slice belongs to,
+/// not from the slice itself: retention runs on the pre-round prefix, whose
+/// carrier may sit inside the round.
+pub(crate) fn retained_user_messages_in_era(
+    post_provenance: bool,
+    messages: &[Message],
+    max_tokens: usize,
+) -> Vec<Message> {
     let mut selected: Vec<Message> = Vec::new();
     let mut remaining = max_tokens;
     for msg in messages.iter().rev() {
@@ -1557,7 +1603,7 @@ pub(crate) fn retained_user_messages(messages: &[Message], max_tokens: usize) ->
         {
             continue;
         }
-        if is_compaction_checkpoint_message(msg) {
+        if is_compaction_checkpoint_message_in_era(msg, post_provenance) {
             continue;
         }
         let tokens: usize = msg

crates/tui/src/compaction/SURVIVAL_CONTRACT.md

@@ -87,6 +87,17 @@ Rust now:
 - `validate_survival_contract` also refuses a missing checkpoint receipt,
   duplicated prior summaries, dropped `/anchor` text, or a placeholder-only
   checkpoint.
+- Checkpoint recognition in the recompaction family is era-scoped. A history
+  that already carries a provenance-stamped carrier (header block plus the
+  provenance block) recognizes only stamped carriers as checkpoints, so a
+  user turn that pastes a bare legacy summary header stays content: it
+  anchors the round, is retained verbatim, and does not count as a duplicated
+  summary. A history without a stamped carrier predates stamping — there the
+  pasted header is indistinguishable from the saved bare carrier, so the
+  loose legacy matching keeps applying. The receipt count reads the
+  replacement in its own era, except that a post-provenance original raises
+  the bar to a stamped carrier: the engine stamps every replacement it
+  builds, and the stamp is the only form request rewriting relocates.
 - `compact_messages_safe` never mutates the caller's live history; the host
   commits only after `Ok`.
 

crates/tui/src/compaction/fixtures/matrix.json

@@ -163,6 +163,9 @@
     {"id":"continuous-round-must-keep-post-checkpoint-results","expect":"fail","original":[{"role":"user","content":[{"type":"text","text":"Continue this task without publishing."}]},{"role":"assistant","content":[{"type":"tool_use","id":"old","name":"File","input":{"path":"old"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"old","content":"evidence old"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem. Old step completed; latest checks remain."}]},{"role":"assistant","content":[{"type":"tool_use","id":"new-a","name":"File","input":{"path":"new-a"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"new-a","content":"evidence new-a"}]},{"role":"assistant","content":[{"type":"tool_use","id":"new-b","name":"File","input":{"path":"new-b"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"new-b","content":"evidence new-b"}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Continue this task without publishing."}]},{"role":"assistant","content":[{"type":"tool_use","id":"old","name":"File","input":{"path":"old"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"old","content":"evidence old"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem. Old step completed; latest checks remain."}]}]},
     {"id":"continuous-round-must-keep-tool-pairs","expect":"fail","original":[{"role":"user","content":[{"type":"text","text":"Continue this task without publishing."}]},{"role":"assistant","content":[{"type":"tool_use","id":"old","name":"File","input":{"path":"old"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"old","content":"evidence old"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem. Old step completed; latest checks remain."}]},{"role":"assistant","content":[{"type":"tool_use","id":"new-a","name":"File","input":{"path":"new-a"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"new-a","content":"evidence new-a"}]},{"role":"assistant","content":[{"type":"tool_use","id":"new-b","name":"File","input":{"path":"new-b"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"new-b","content":"evidence new-b"}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Continue this task without publishing."}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"new-a","content":"evidence new-a"}]},{"role":"assistant","content":[{"type":"tool_use","id":"new-b","name":"File","input":{"path":"new-b"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"new-b","content":"evidence new-b"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem. Old step completed; latest checks remain."}]}]},
     {"id":"legacy-v2-checkpoint-replaced-by-handoff-note","expect":"pass","last_round_start":0,"original":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"test session_store::roundtrip ... FAILED"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem and produced a summary.\n\nfirst pass"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"test session_store::roundtrip ... FAILED"}]},{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nfix the failing test"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]}]},
-    {"id":"quoted-handoff-marker-is-user-text","expect":"fail","last_round_start":0,"original":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"test session_store::roundtrip ... FAILED"}]},{"role":"user","content":[{"type":"text","text":"What is in the Codewhale handoff note?"}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"test session_store::roundtrip ... FAILED"}]},{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nfix the failing test"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]}]}
+    {"id":"quoted-handoff-marker-is-user-text","expect":"fail","last_round_start":0,"original":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"test session_store::roundtrip ... FAILED"}]},{"role":"user","content":[{"type":"text","text":"What is in the Codewhale handoff note?"}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"test session_store::roundtrip ... FAILED"}]},{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nfix the failing test"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]}]},
+    {"id":"pasted-legacy-header-survives-post-provenance","expect":"pass","last_round_start":0,"original":[{"role":"user","content":[{"type":"text","text":"Run the suite now."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"ok"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem and produced a summary.\n\nsuite finished"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]},{"role":"assistant","content":[{"type":"text","text":"done"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem\n\nEarlier turns of another session, pasted verbatim."}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nrun the suite"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]},{"role":"user","content":[{"type":"text","text":"Run the suite now."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"ok"}]},{"role":"assistant","content":[{"type":"text","text":"done"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem\n\nEarlier turns of another session, pasted verbatim."}]}]},
+    {"id":"pasted-legacy-header-dropped-post-provenance","expect":"fail","last_round_start":0,"original":[{"role":"user","content":[{"type":"text","text":"Run the suite now."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"ok"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem and produced a summary.\n\nsuite finished"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]},{"role":"assistant","content":[{"type":"text","text":"done"}]},{"role":"user","content":[{"type":"text","text":"Another language model started to solve this problem\n\nEarlier turns of another session, pasted verbatim."}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nrun the suite"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]},{"role":"user","content":[{"type":"text","text":"Run the suite now."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"ok"}]},{"role":"assistant","content":[{"type":"text","text":"done"}]}]},
+    {"id":"pasted-modern-header-dropped-post-provenance","expect":"fail","last_round_start":0,"original":[{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"ok"}]},{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nfix the failing test"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]},{"role":"assistant","content":[{"type":"text","text":"done"}]},{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nfix the failing test"}]}],"replacement":[{"role":"user","content":[{"type":"text","text":"Codewhale handoff note. Earlier turns of this session were condensed to make room.\n\n## Objective\nfix the failing test"},{"type":"text","text":"<!-- codewhale.compaction-checkpoint.v1 -->"}]},{"role":"user","content":[{"type":"text","text":"Run the failing test."}]},{"role":"assistant","content":[{"type":"tool_use","id":"live","name":"Bash","input":{"command":"cargo test"}}]},{"role":"user","content":[{"type":"tool_result","tool_use_id":"live","content":"ok"}]},{"role":"assistant","content":[{"type":"text","text":"done"}]}]}
   ]
 }