fix: budget gate and loop-breaker refusals exit without a traceback (Gitea #147)

Files changed:
- CHANGES.md
- VERSION
- tools/chemenu/cli.py
- tools/chemenu/commands/run_budget.py
- tools/chemenu/tests/test_run_budget.py

tools/chemenu/cli.py

@@ -266,13 +266,13 @@ _typer_click_core.Command.format_help = _contract_format_help
 
 
 def main() -> None:
-    # Iteration Budget Gate / Loop-Breaker (see the tooling contract's
-    # "Iteration and Cost Limits"): recorded and enforced here, once per
-    # process, before Typer dispatches to any subcommand - so it covers every
-    # command uniformly and cannot be bypassed by the calling agent skipping a
-    # step. Help output is never counted: discovering a command's options is
-    # not iteration on the wiki, and charging for it would discourage exactly
-    # the behavior the skills ask for.
+    # Iteration Budget Gate / Loop-Breaker (see instructions/gates.md
+    # "Iteration Budget Gate and loop-breaker"): recorded and enforced here,
+    # once per process, before Typer dispatches to any subcommand - so it
+    # covers every command uniformly and cannot be bypassed by the calling
+    # agent skipping a step. Help output is never counted: discovering a
+    # command's options is not iteration on the wiki, and charging for it
+    # would discourage exactly the behavior the skills ask for.
     #
     # Tracing sits at the same point for the same reason - one place that no
     # command can route around. It is not the same set, though: the budget
@@ -284,7 +284,19 @@ def main() -> None:
         override = "--override-budget" in argv
         filtered = [a for a in argv if a != "--override-budget"]
         command = filtered[0] if filtered else ""
-        charged = run_budget.record_and_check(command, filtered[1:], override)
+        # A gate refusal leaves `record_and_check` through `_util.fail()`,
+        # which raises `typer.Exit` (Gitea #147). That is fine inside Typer's
+        # own dispatch - Click catches it - but this call runs *before*
+        # `app()` ever starts, so nothing catches it here: left alone, the
+        # process would exit 1 correctly but print a Python traceback right
+        # after the `ERROR` line, which AGENTS.md § Gates asks a session to
+        # show a human and stop on. A traceback reads as a crash, not a gate,
+        # and invites exactly the retry the message forbids (see #52).
+        try:
+            charged = run_budget.record_and_check(command, filtered[1:], override)
+        except typer.Exit as exc:
+            code = exc.exit_code
+            sys.exit(code if isinstance(code, int) else (0 if code is None else 1))
         sys.argv = [sys.argv[0], *filtered]
         _run_traced(command, filtered[1:], charged)
         return

tools/chemenu/commands/run_budget.py

@@ -33,7 +33,7 @@ from chemenu.session import session_id as _shared_session_id
 from chemenu.session import session_id_source as _shared_session_id_source
 from chemenu.telemetry import emit
 
-app = typer.Typer(help="Session iteration/cost budget gate (see the tooling contract's 'Iteration and Cost Limits').")
+app = typer.Typer(help="Session iteration/cost budget gate (see instructions/gates.md 'Iteration Budget Gate and loop-breaker').")
 
 STATE_DIR = config.ROOT / "tools" / ".wikitool_session"
 STATE_FILE = STATE_DIR / "budget.json"
@@ -206,8 +206,8 @@ def loop_breaker_message(call_signature: str, loop_window: int) -> str:
     return (
         f"Loop-Breaker: the last {loop_window} wikitool calls in this session were "
         f"identical ('{call_signature}'). This usually means the agent is stuck retrying "
-        "the same failing operation instead of changing approach - per the tooling contract's "
-        "Tool Error Contracts, that is exactly the case for stopping and escalating rather than "
+        "the same failing operation instead of changing approach - per AGENTS.md's "
+        "Tool error contract, that is exactly the case for stopping and escalating rather than "
         "retrying again. Stop, explain the situation to the user, and get explicit direction "
         "before continuing. Only re-run with --override-budget once the user has confirmed "
         "the repeat is intentional - never add it on the agent's own initiative."
@@ -217,7 +217,8 @@ def loop_breaker_message(call_signature: str, loop_window: int) -> str:
 def call_limit_message(count: int, call_limit: int) -> str:
     return (
         f"Iteration Budget Gate: this session has made {count} wikitool calls, exceeding the "
-        f"limit of {call_limit}. Per the tooling contract's 'Iteration and Cost Limits' section, a "
+        f"limit of {call_limit}. Per instructions/gates.md's 'Iteration Budget Gate and "
+        "loop-breaker' section, a "
         "single task should typically need roughly 5-15 calls (simple) or 20-35 (complex multi-tool "
         "workflow like wiki-ingest/wiki-lint). This far past that band is a documented sign of poor "
         "task decomposition or a stuck loop. Stop, summarize progress and the blocker to the "
@@ -304,8 +305,8 @@ def refund() -> None:
     """Give the current session its last charged slot back.
 
     Called when the command declined instead of acting: a rejected argument,
-    or a read-only check reporting findings (`_util.fail`, exit 1). The
-    tooling contract answers a rejected argument with "fix it and retry once",
+    or a read-only check reporting findings (`_util.fail`, exit 1). AGENTS.md's
+    Tool error contract answers a rejected argument with "fix it and retry once",
     so charging for the rejection makes the prescribed response cost two slots
     for one operation - and the budget exists to bound iteration on the wiki,
     which a call that changed nothing did not do.

tools/chemenu/tests/test_run_budget.py

@@ -47,11 +47,23 @@ def test_call_limit_trips_past_threshold():
 
 def test_call_limit_message_mentions_contract_and_override():
     message = run_budget.call_limit_message(61, 60)
-    assert "Iteration and Cost Limits" in message
+    assert "Iteration Budget Gate and loop-breaker" in message
     assert "--override-budget" in message
     assert "61" in message and "60" in message
 
 
+def test_message_sections_exist_in_the_documents_they_cite():
+    """Both refusal messages point a reader at a section by name (Gitea
+    #147: they used to point at "the tooling contract's 'Iteration and Cost
+    Limits'" and "...Tool Error Contracts", neither of which exists). Pin
+    that the cited headings are real, so the two drift apart again only if
+    this test is touched too."""
+    agents_md = (config._PACKAGE_ROOT / "AGENTS.md").read_text(encoding="utf-8")
+    gates_md = (config._PACKAGE_ROOT / "instructions" / "gates.md").read_text(encoding="utf-8")
+    assert "## Tool error contract" in agents_md
+    assert "## Iteration Budget Gate and loop-breaker" in gates_md
+
+
 def test_record_and_check_reports_whether_it_charged():
     assert run_budget.record_and_check("new", ["entity"], override=False) is True
     assert run_budget.record_and_check("search", ["anything"], override=False) is False
@@ -348,3 +360,76 @@ def test_the_loop_breaker_trips_across_separate_shells(tmp_path, monkeypatch):
     result = _spawn_call(tmp_path, monkeypatch, command="xref", args=args)
     assert result.returncode != 0
     assert "Loop-Breaker" in result.stdout
+
+
+# --- a refusal exits without a traceback (Gitea #147) ---
+#
+# The two tests above call `run_budget.record_and_check` directly, so they
+# never exercise `cli.main()` - the place `_util.fail()`'s `typer.Exit` used
+# to go uncaught, since it is raised *before* `app()` starts and nothing
+# outside `app()` catches it. These drive the real entry point
+# (`python -m chemenu.cli`, not a `-c` snippet) so the whole `main()` codepath
+# runs, and check the property the fix promises: exit 1, no traceback on
+# either stream, `gate.refused` recorded, no `wikitool.call` for the refused
+# invocation, and the budget counter left exactly where it was.
+
+def _spawn_cli_call(tmp_path, trace_dir, monkeypatch, *, session_id, args):
+    monkeypatch.setenv("CHEMENU_ROOT", str(tmp_path))
+    monkeypatch.setenv("WIKI_TRACE_DIR", str(trace_dir))
+    monkeypatch.setenv("WIKITOOL_SESSION_ID", session_id)
+    monkeypatch.delenv("CLAUDE_CODE_SESSION_ID", raising=False)
+    return subprocess.run(
+        [sys.executable, "-m", "chemenu.cli", *args],
+        cwd=config._PACKAGE_ROOT / "tools",
+        capture_output=True, text=True,
+    )
+
+
+def _trace_events(trace_dir, session_id):
+    path = trace_dir / session_id / "trace.jsonl"
+    return [json.loads(line) for line in path.read_text(encoding="utf-8").splitlines() if line]
+
+
+def test_loop_breaker_refusal_has_no_traceback(tmp_path, monkeypatch):
+    session_id = "test-147-loop"
+    trace_dir = tmp_path / "trace"
+    args = ["xref", "add", "--a", "X", "--b", "Y"]
+    for _ in range(run_budget.DEFAULT_LOOP_WINDOW):
+        _spawn_cli_call(tmp_path, trace_dir, monkeypatch, session_id=session_id, args=args)
+
+    result = _spawn_cli_call(tmp_path, trace_dir, monkeypatch, session_id=session_id, args=args)
+    assert result.returncode == 1
+    assert result.stdout.startswith("ERROR Loop-Breaker")
+    assert "Traceback" not in result.stdout
+    assert "Traceback" not in result.stderr
+
+    events = _trace_events(trace_dir, session_id)
+    assert [e["event"] for e in events[-1:]] == ["gate.refused"]
+    assert events[-1]["attrs"]["gate"] == "loop-breaker"
+    assert sum(e["event"] == "wikitool.call" for e in events) == run_budget.DEFAULT_LOOP_WINDOW
+
+    state = json.loads((tmp_path / "tools" / ".wikitool_session" / "budget.json").read_text())
+    assert state[session_id]["count"] == run_budget.DEFAULT_LOOP_WINDOW
+
+
+def test_iteration_budget_refusal_has_no_traceback(tmp_path, monkeypatch):
+    session_id = "test-147-limit"
+    trace_dir = tmp_path / "trace"
+    for i in range(run_budget.DEFAULT_CALL_LIMIT):
+        _spawn_cli_call(tmp_path, trace_dir, monkeypatch, session_id=session_id, args=["lint", f"--pass-{i}"])
+
+    result = _spawn_cli_call(
+        tmp_path, trace_dir, monkeypatch, session_id=session_id, args=["lint", "--one-too-many"]
+    )
+    assert result.returncode == 1
+    assert result.stdout.startswith("ERROR Iteration Budget Gate")
+    assert "Traceback" not in result.stdout
+    assert "Traceback" not in result.stderr
+
+    events = _trace_events(trace_dir, session_id)
+    assert [e["event"] for e in events[-1:]] == ["gate.refused"]
+    assert events[-1]["attrs"]["gate"] == "iteration-budget"
+    assert sum(e["event"] == "wikitool.call" for e in events) == run_budget.DEFAULT_CALL_LIMIT
+
+    state = json.loads((tmp_path / "tools" / ".wikitool_session" / "budget.json").read_text())
+    assert state[session_id]["count"] == run_budget.DEFAULT_CALL_LIMIT