elitecoder · Oct 19, 2026 · Oct 1, 2026 · Oct 1, 2026 · Oct 19, 2026 · Oct 19, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -56,6 +56,16 @@ The version is carried in `pyproject.toml` and `src/assistant/__init__.py`
 - Add an attention overview with compact task cards, expandable return notes,
   and reminders to finish older pending work before starting another task.
 
+### Changed
+- Move the `balanced` model tier from Sonnet 4.6 to Sonnet 5.5 on Bedrock, the
+  Anthropic API, and Vertex. The warm Slack session, the Observer, the brief
+  narrator, and the strategist use this tier. Restart
+  `com.assistant.assistant-comms` to pick it up; the restarted daemon replaces
+  a warm session on the old model before its next Slack message. The Observer
+  and fleet evals now default to this tier's model, and their qualification
+  hashes include `model_tiers.py`. Cost estimates price Sonnet 5 models at $2
+  and $10 per million input and output tokens.
+
 ### Fixed
 - Bring the warm Slack session up again on Claude Code 2.1.303 and cmux 0.65.
   Claude Code now writes several hundred KB of records right after each prompt,

diff --git a/bin/metering.py b/bin/metering.py
@@ -64,6 +64,7 @@
 _PRICE_PER_MTOK = (
     ("opus", (5.0, 25.0)),
     ("haiku", (1.0, 5.0)),
+    ("sonnet-5", (2.0, 10.0)),
     ("sonnet", (3.0, 15.0)),
     ("glm-5.2", (1.40, 4.40)),
 )

diff --git a/docs/assistant-comms-onboarding.md b/docs/assistant-comms-onboarding.md
@@ -79,7 +79,7 @@ To stop: `launchctl bootout gui/$UID/com.assistant.assistant-comms`.
 |---|---|---|
 | `SLACK_BOT_TOKEN` | ✅ | `xoxb-` bot token (from `~/.zprofile`). Never stored in config.json. |
 | `SLACK_PING_TARGET` | optional | `C…` private channel (recommended) or `U…` user (DMed); overrides `config.slack.target`. |
-| `COMMS_MODEL` | optional | warm-session model (default Sonnet 4.6 1M). |
+| `COMMS_MODEL` | optional | warm-session model (default Sonnet 5.5 1M). |
 | `COMMS_SLACK_POLL_SEC` | optional | inbound poll interval (default 3s). |
 | `COMMS_SUBMIT_ATTEMPTS` / `COMMS_SUBMIT_WAIT_SEC` | optional | Enter presses to try when a typed prompt doesn't reach the transcript, and seconds to wait after each (default 3 and 15s). |
 | `COMMS_LIVENESS_ATTEMPTS` / `COMMS_LIVENESS_RETRY_SEC` | optional | looks at a workspace cmux didn't answer about before calling it unknown, and seconds between them (default 3 and 3s). |

diff --git a/evals/fleet/run.py b/evals/fleet/run.py
@@ -16,16 +16,19 @@
 EVAL_DIR = Path(__file__).resolve().parent
 REPO = EVAL_DIR.parents[1]
 BIN = REPO / "bin"
-if str(BIN) not in sys.path:
-    sys.path.insert(0, str(BIN))
+SRC = REPO / "src"
+for path in (BIN, SRC):
+    if str(path) not in sys.path:
+        sys.path.insert(0, str(path))
 import llm_runner
+from assistant import model_tiers
 
 CLAUDE_BIN = os.environ.get(
     "CLAUDE_BIN", str(Path.home() / ".local/bin/claude"))
 DROID_BIN = os.environ.get(
     "DROID_BIN", str(Path.home() / ".local/bin/droid"))
 CLAUDE_MODEL = os.environ.get(
-    "EVAL_CLAUDE_MODEL", "us.anthropic.claude-sonnet-4-6[1m]")
+    "EVAL_CLAUDE_MODEL", model_tiers.model_for("balanced", long_context=True))
 DROID_MODEL = os.environ.get("EVAL_DROID_MODEL", "glm-5.2")
 TIMEOUT = int(os.environ.get("EVAL_TIMEOUT_SEC", "240"))
 REPORT = EVAL_DIR / "last-run.json"
@@ -35,6 +38,7 @@ def qualification_input_hashes() -> dict[str, str]:
     paths = [
         Path(__file__),
         BIN / "llm_runner.py",
+        SRC / "assistant/model_tiers.py",
         REPO / "prompts/triage-batch-prompt.md",
         REPO / "prompts/strategist-draft-prompt.md",
         REPO / "prompts/brief-narrator-prompt.md",

diff --git a/evals/observer/README.md b/evals/observer/README.md
@@ -9,7 +9,7 @@ workspace states. Each fixture is one test case.
 ./run.py                       # all fixtures
 ./run.py 01-ws97-trap-no-pr-mid-audit
 ./run.py --list                # list fixture names
-EVAL_MODEL=us.anthropic.claude-sonnet-4-6[1m] ./run.py
+EVAL_CLAUDE_MODEL='claude-sonnet-5-5[1m]' ./run.py --provider claude
 ```
 
 `run.py` spawns a one-shot headless `claude --print` per fixture, feeding

diff --git a/evals/observer/run.py b/evals/observer/run.py
@@ -14,7 +14,7 @@
 Usage:
   ./run.py                       # all fixtures
   ./run.py ws97-trap             # one fixture
-  EVAL_MODEL=us.anthropic.claude-sonnet-4-6[1m] ./run.py
+  EVAL_CLAUDE_MODEL='claude-sonnet-5-5[1m]' ./run.py --provider claude
 """
 from __future__ import annotations
 
@@ -33,14 +33,17 @@
 REPO = EVAL_DIR.parents[1]
 OBSERVER_PROMPT = REPO / "prompts/observer-batch-prompt.md"
 BIN = REPO / "bin"
-if str(BIN) not in sys.path:
-    sys.path.insert(0, str(BIN))
+SRC = REPO / "src"
+for path in (BIN, SRC):
+    if str(path) not in sys.path:
+        sys.path.insert(0, str(path))
 import llm_runner
+from assistant import model_tiers
 
 CLAUDE_BIN = os.environ.get("CLAUDE_BIN", str(Path.home() / ".local/bin/claude"))
 DROID_BIN = os.environ.get("DROID_BIN", str(Path.home() / ".local/bin/droid"))
 CLAUDE_MODEL = os.environ.get(
-    "EVAL_CLAUDE_MODEL", "us.anthropic.claude-sonnet-4-6[1m]")
+    "EVAL_CLAUDE_MODEL", model_tiers.model_for("balanced", long_context=True))
 DROID_MODEL = os.environ.get("EVAL_DROID_MODEL", "glm-5.2")
 TIMEOUT_SEC = int(os.environ.get("EVAL_TIMEOUT_SEC", "180"))
 REPORT_PATH = EVAL_DIR / "last-run.json"
@@ -76,6 +79,7 @@ def qualification_input_hashes() -> dict[str, str]:
         Path(__file__),
         BIN / "llm_runner.py",
         BIN / "pulse.py",
+        SRC / "assistant/model_tiers.py",
         *sorted(path for path in FIXTURES_DIR.rglob("*") if path.is_file()),
     ]
     return {

diff --git a/src/assistant/model_tiers.py b/src/assistant/model_tiers.py
@@ -41,17 +41,17 @@
 _DEFAULTS = {
     "bedrock": {
         "frontier": "us.anthropic.claude-opus-4-8",
-        "balanced": "us.anthropic.claude-sonnet-4-6",
+        "balanced": "us.anthropic.claude-sonnet-5-5",
         "cheap":    "us.anthropic.claude-haiku-4-5",
     },
     "anthropic": {
         "frontier": "claude-opus-4-8",
-        "balanced": "claude-sonnet-4-6",
+        "balanced": "claude-sonnet-5-5",
         "cheap":    "claude-haiku-4-5",
     },
     "vertex": {
         "frontier": "claude-opus-4-8",
-        "balanced": "claude-sonnet-4-6",
+        "balanced": "claude-sonnet-5-5",
         "cheap":    "claude-haiku-4-5",
     },
 }

diff --git a/tests/test_comms_session.py b/tests/test_comms_session.py
@@ -68,7 +68,7 @@ def test_warm_launch_declares_bedrock_backend_and_keeps_1m_context(monkeypatch):
     monkeypatch.setenv("CLAUDE_CODE_USE_BEDROCK", "1")
     cmd = cs._warm_launch(ag.CLAUDE)
     assert cmd.startswith("CLAUDE_CODE_USE_BEDROCK=1 ")
-    assert "us.anthropic.claude-sonnet-4-6[1m]" in cmd
+    assert "us.anthropic.claude-sonnet-5-5[1m]" in cmd
 
 
 def test_warm_launch_declares_non_bedrock_backend_and_still_gets_1m_context(monkeypatch):
@@ -120,13 +120,13 @@ def test_resolve_warm_model_and_backend_respects_env(monkeypatch):
     monkeypatch.setenv("CLAUDE_CODE_USE_BEDROCK", "1")
     model, backend, pinned = cs._resolve_warm_model_and_backend()
     assert backend == "bedrock"
-    assert model == "us.anthropic.claude-sonnet-4-6[1m]"
+    assert model == "us.anthropic.claude-sonnet-5-5[1m]"
     assert pinned is False
 
     monkeypatch.setenv("CLAUDE_CODE_USE_BEDROCK", "0")
     model, backend, pinned = cs._resolve_warm_model_and_backend()
     assert backend == "anthropic"
-    assert model == "claude-sonnet-4-6[1m]"
+    assert model == "claude-sonnet-5-5[1m]"
     assert pinned is False
 
     monkeypatch.setenv("COMMS_MODEL", "my-pinned-id")

diff --git a/tests/test_metering.py b/tests/test_metering.py
@@ -218,6 +218,11 @@ def test_observer_usage_falls_back_to_estimate(self):
         # 1000 in @ $3/M + tokens_out @ $15/M — sonnet rates
         self.assertGreater(u["cost_usd"], 0)
 
+    def test_sonnet_5_is_priced_below_sonnet_4(self):
+        self.assertEqual(self.mod.price_per_mtok("claude-sonnet-5-5[1m]"), (2.0, 10.0))
+        self.assertEqual(self.mod.price_per_mtok("us.anthropic.claude-sonnet-5-5"), (2.0, 10.0))
+        self.assertEqual(self.mod.price_per_mtok("us.anthropic.claude-sonnet-4-6[1m]"), (3.0, 15.0))
+
     def test_sum_usage_source_mixing(self):
         cli = {"tokens_in": 10, "tokens_out": 1, "cost_usd": 0.1, "source": "cli"}
         est = {"tokens_in": 20, "tokens_out": 2, "cost_usd": 0.2, "source": "estimated"}

diff --git a/tests/test_model_tiers.py b/tests/test_model_tiers.py
@@ -92,7 +92,7 @@ def test_bedrock_ids(self):
         os.environ["CLAUDE_CODE_USE_BEDROCK"] = "1"
         # frontier is a CURRENT Opus (not the deprecated 4-1 the review flagged)
         self.assertEqual(mt.model_for("frontier"), "us.anthropic.claude-opus-4-8")
-        self.assertEqual(mt.model_for("balanced"), "us.anthropic.claude-sonnet-4-6")
+        self.assertEqual(mt.model_for("balanced"), "us.anthropic.claude-sonnet-5-5")
         self.assertEqual(mt.model_for("cheap"), "us.anthropic.claude-haiku-4-5")
 
     def test_anthropic_ids_are_bare(self):
@@ -113,15 +113,15 @@ def test_provider_hint_pins_id_format_independent_of_detection(self):
     def test_long_context_suffix_is_opt_in_on_bedrock_and_anthropic(self):
         os.environ["CLAUDE_CODE_USE_BEDROCK"] = "1"
         self.assertEqual(mt.model_for("balanced", long_context=True),
-                         "us.anthropic.claude-sonnet-4-6[1m]")
+                         "us.anthropic.claude-sonnet-5-5[1m]")
         # not requested → no suffix (the mem0 path stays clean)
         self.assertNotIn("[1m]", mt.model_for("cheap"))
         # direct Anthropic ALSO gets it when requested — verified live: the
         # operator's non-Bedrock ~/.zprofile alias runs `[1m]` on a bare id
         # (2026-09-05 — an earlier version wrongly called this Bedrock-only).
         os.environ["MODEL_PROVIDER"] = "anthropic"
         self.assertEqual(mt.model_for("balanced", long_context=True),
-                         "claude-sonnet-4-6[1m]")
+                         "claude-sonnet-5-5[1m]")
 
     def test_per_tier_override_is_verbatim(self):
         os.environ["CLAUDE_CODE_USE_BEDROCK"] = "1"