feat(models): update the capable-tier Sonnet to Claude Sonnet 5 (#1198)

Swaps the default "capable" model from claude-sonnet-4-6 to the newly
released claude-sonnet-5 (GA 2026-06-09) across the registry, adaptive
routing, providers, telemetry, token estimation, and the literal
model_id defaults scattered through the codebase. Verified the ID
against the live Anthropic models doc before changing anything.

Pricing is unchanged: $3/$15 per MTok standard (introductory $2/$10
through 2026-08-31). 1M context, 128K max output, adaptive thinking,
effort defaults to high. Sonnet 4.6 is now a legacy model.

- Full claude-sonnet-4-6 -> claude-sonnet-5 swap across src/ + tests/
  (65 files); matching test expectations updated so CI stays green.
- Registry CAPABLE ModelInfo + TIER_PRICING comment refreshed.
- Stale "Sonnet 4.6" prose comments updated to "Sonnet 5".
- Left claude-sonnet-4-5 (legacy 4.5) references untouched.
- CHANGELOG Unreleased "Changed" entry added.

962 model/routing/pricing/telemetry/provider tests pass. The only
failures are the live-API integration tests in
tests/models/test_sonnet_opus_fallback.py (skipif HAS_API_KEY) — a
local creditless-key 400, skipped in CI; the new ID is accepted (no
404), confirming the swap.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: silversurfer562

CHANGELOG.md

@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- **Default "capable" model is now Claude Sonnet 5
+  (`claude-sonnet-5`).** Replaces `claude-sonnet-4-6` across the model
+  registry, adaptive routing, providers, telemetry, and token
+  estimation. Pricing is unchanged ($3/$15 per MTok standard;
+  introductory $2/$10 through 2026-08-31). 1M context, 128K max output,
+  adaptive thinking; `effort` defaults to `high`.
+
 ## [9.3.0] — 2026-06-30
 
 **Dynamic communication to improve the human/AI exchange.** Attune now

src/attune/agent_factory/base.py

@@ -307,11 +307,11 @@ def get_model_for_tier(self, tier: str, provider: str = "anthropic") -> str:
             defaults = {
                 "anthropic": {
                     "cheap": "claude-haiku-4-5",
-                    "capable": "claude-sonnet-4-6",
+                    "capable": "claude-sonnet-5",
                     "premium": "claude-opus-4-8",
                 },
             }
             return defaults.get(provider, defaults["anthropic"]).get(
                 tier,
-                "claude-sonnet-4-6",
+                "claude-sonnet-5",
             )

src/attune/agents/release/release_models.py

@@ -46,7 +46,7 @@
 
 MODEL_CONFIG = {
     "cheap": "claude-haiku-4-5",
-    "capable": "claude-sonnet-4-6",
+    "capable": "claude-sonnet-5",
     "premium": "claude-opus-4-8",
 }
 

src/attune/cli_commands/memory_agent.py

@@ -25,7 +25,7 @@
 
 # CAPABLE-tier stable alias — tracks the latest Sonnet minor, never retires
 # (avoids pinning a dated snapshot that EOLs).
-_DEFAULT_MODEL = "claude-sonnet-4-6"
+_DEFAULT_MODEL = "claude-sonnet-5"
 # Required beta header for the memory_20250818 tool + context management.
 _MEMORY_BETA = "context-management-2025-06-27"
 _DEFAULT_MAX_TOKENS = 4096

src/attune/cli_minimal.py

@@ -455,7 +455,7 @@ def _add_misc_subparsers(subparsers: argparse._SubParsersAction) -> None:
         "--path", help="Memory namespace root the agent addresses (default /memories)"
     )
     memory_agent_parser.add_argument(
-        "--model", help="Model id (default: claude-sonnet-4-6, the CAPABLE tier)"
+        "--model", help="Model id (default: claude-sonnet-5, the CAPABLE tier)"
     )
     memory_agent_parser.add_argument("--user-id", dest="user_id", help="Namespace memory per user")
     memory_agent_parser.add_argument(

src/attune/config/agent_config.py

@@ -149,14 +149,14 @@ def get_model_id(self) -> str:
         models = {
             Provider.ANTHROPIC: {
                 ModelTier.CHEAP: "claude-haiku-4-5",
-                ModelTier.CAPABLE: "claude-sonnet-4-6",
+                ModelTier.CAPABLE: "claude-sonnet-5",
                 ModelTier.PREMIUM: "claude-opus-4-8",
             },
         }
 
         return models.get(self.provider, {}).get(
             self.model_tier,
-            "claude-sonnet-4-6",  # Fallback
+            "claude-sonnet-5",  # Fallback
         )
 
     def for_book_production(self) -> "BookProductionConfig":

src/attune/config/sections/routing.py

@@ -33,7 +33,7 @@ class RoutingConfig:
 
     default_tier: Literal["cheap", "capable", "premium"] = "capable"
     cheap_model: str = "claude-haiku-4-5"
-    capable_model: str = "claude-sonnet-4-6"
+    capable_model: str = "claude-sonnet-5"
     premium_model: str = "claude-opus-4-8"
     auto_tier_selection: bool = True
     cost_optimization: bool = True
@@ -67,7 +67,7 @@ def from_dict(cls, data: dict) -> "RoutingConfig":
         return cls(
             default_tier=data.get("default_tier", "capable"),
             cheap_model=data.get("cheap_model", "claude-haiku-4-5"),
-            capable_model=data.get("capable_model", "claude-sonnet-4-6"),
+            capable_model=data.get("capable_model", "claude-sonnet-5"),
             premium_model=data.get("premium_model", "claude-opus-4-8"),
             auto_tier_selection=data.get("auto_tier_selection", True),
             cost_optimization=data.get("cost_optimization", True),

src/attune/config/xml_config.py

@@ -56,8 +56,8 @@ class AdaptiveConfig:
     model_tier_mapping: dict[str, str] = field(
         default_factory=lambda: {
             "simple": "claude-haiku-4-5",
-            "moderate": "claude-sonnet-4-6",
-            "complex": "claude-sonnet-4-6",
+            "moderate": "claude-sonnet-5",
+            "complex": "claude-sonnet-5",
             "very_complex": "claude-opus-4-8",
         },
     )

src/attune/help/polish.py

@@ -113,7 +113,7 @@ def _call_llm(
         # Stable alias — claude-sonnet-4-20250514 retires 2026-06-15.
         # The stable alias routes to the same checkpoint and stays
         # valid across model upgrades.
-        model="claude-sonnet-4-6",
+        model="claude-sonnet-5",
         max_tokens=4096,
         system=_SYSTEM_PROMPT,
         messages=[{"role": "user", "content": user_message}],

src/attune/llm/core.py

@@ -231,7 +231,7 @@ def _create_provider(
         if provider == "anthropic":
             return AnthropicProvider(
                 api_key=api_key,
-                model=model or "claude-sonnet-4-6",
+                model=model or "claude-sonnet-5",
                 **kwargs,
             )
         raise ValueError(f"Unknown provider: {provider}")