Add Claude Opus 5 support

dev-notes/claude-opus-5-model-support.md

@@ -0,0 +1,48 @@
+# Claude Opus 5 model support
+
+## What changed
+
+Tau's direct Anthropic catalog now includes `claude-opus-5` with metadata from
+Anthropic's July 24, 2026 launch documentation:
+
+- 1,000,000-token context window
+- 128,000-token maximum output
+- text and image input
+- $5 / million input tokens and $25 / million output tokens
+- adaptive thinking with `low`, `medium`, `high`, `xhigh`, and `max` effort
+
+Tau retains `claude-sonnet-4-6` as Anthropic's default model. Users opt into
+Opus 5 through `/model` or `--provider anthropic -m claude-opus-5`.
+
+## Thinking compatibility
+
+Tau has six UI levels while Opus 5 has five enabled-thinking effort levels plus
+a disabled mode. `minimal` is unavailable for this model. Tau maps `xhigh` to
+Anthropic's `max` wire value because both represent Tau's top reasoning tier.
+`off` now sends `thinking: {"type": "disabled"}` explicitly; omitting the field
+would not work because Opus 5 enables adaptive thinking by default.
+
+## Architecture
+
+This remains a catalog and provider-adapter change:
+
+- `tau_coding` owns model discovery, metadata, and thinking-level mapping.
+- `tau_ai` serializes the resulting Anthropic Messages API request.
+- `tau_agent` remains provider-independent.
+
+## Verification
+
+Run:
+
+```bash
+uv run pytest tests/test_provider_catalog.py tests/test_provider_config.py tests/test_tau_ai.py
+uv run ruff check .
+uv run ruff format --check .
+uv run mypy
+```
+
+Official sources:
+
+- https://platform.claude.com/docs/en/about-claude/models/whats-new-opus-5
+- https://platform.claude.com/docs/en/about-claude/models/overview
+- https://platform.claude.com/docs/en/release-notes/overview

src/tau_ai/anthropic.py

@@ -362,7 +362,9 @@ def _build_messages_payload(
         ),
         "messages": [_anthropic_message(message) for message in messages],
     }
-    if thinking_mode == "adaptive" and thinking_effort is not None:
+    if thinking_mode == "disabled":
+        payload["thinking"] = {"type": "disabled"}
+    elif thinking_mode == "adaptive" and thinking_effort is not None:
         payload["thinking"] = {"type": "adaptive", "display": "summarized"}
         payload["output_config"] = {"effort": thinking_effort}
     elif thinking_budget_tokens is not None:

src/tau_coding/data/catalog.toml

@@ -518,7 +518,7 @@ base_url = "https://api.anthropic.com"
 api_key_env = "ANTHROPIC_API_KEY"
 credential_name = "anthropic"
 auth_methods = ["api_key", "oauth"]
-models = ["claude-fable-5", "claude-haiku-4-5", "claude-haiku-4-5-20251001", "claude-opus-4-1", "claude-opus-4-1-20250805", "claude-opus-4-5", "claude-opus-4-5-20251101", "claude-opus-4-6", "claude-opus-4-7", "claude-sonnet-4-5", "claude-sonnet-4-5-20250929", "claude-sonnet-4-6", "claude-sonnet-5"]
+models = ["claude-fable-5", "claude-haiku-4-5", "claude-haiku-4-5-20251001", "claude-opus-4-1", "claude-opus-4-1-20250805", "claude-opus-4-5", "claude-opus-4-5-20251101", "claude-opus-4-6", "claude-opus-4-7", "claude-opus-5", "claude-sonnet-4-5", "claude-sonnet-4-5-20250929", "claude-sonnet-4-6", "claude-sonnet-5"]
 default_model = "claude-sonnet-4-6"
 docs_url = "https://docs.anthropic.com"
 api = "anthropic-messages"
@@ -536,6 +536,7 @@ claude-opus-4-5 = 200000
 claude-opus-4-5-20251101 = 200000
 claude-opus-4-6 = 1000000
 claude-opus-4-7 = 1000000
+claude-opus-5 = 1000000
 claude-sonnet-4-5 = 200000
 claude-sonnet-4-5-20250929 = 200000
 claude-sonnet-4-6 = 1000000
@@ -621,6 +622,17 @@ cost = { input = 5, output = 25, cacheRead = 0.5, cacheWrite = 6.25 }
 thinking_level_map = { xhigh = "xhigh" }
 unsupported_thinking_levels = ["minimal"]
 
+[providers.model_metadata.claude-opus-5]
+name = "Claude Opus 5"
+reasoning = true
+input = ["text", "image"]
+context_window = 1000000
+max_tokens = 128000
+compat = { forceAdaptiveThinking = true }
+cost = { input = 5, output = 25, cacheRead = 0.5, cacheWrite = 6.25 }
+thinking_level_map = { xhigh = "max" }
+unsupported_thinking_levels = ["minimal"]
+
 [providers.model_metadata.claude-sonnet-4-5]
 name = "Claude Sonnet 4.5 (latest)"
 reasoning = true

src/tau_coding/provider_config.py

@@ -1528,7 +1528,9 @@ def anthropic_config_from_provider(
             model=selected_model,
             thinking_level=thinking_level,
         ),
-        thinking_mode=_anthropic_thinking_mode(provider, selected_model),
+        thinking_mode=_anthropic_thinking_mode(
+            provider, selected_model, thinking_level=thinking_level
+        ),
     )
 
 
@@ -1688,9 +1690,16 @@ def _reasoning_effort_from_anthropic_provider(
     return mapped or normalized
 
 
-def _anthropic_thinking_mode(provider: AnthropicProviderConfig, model: str) -> str:
+def _anthropic_thinking_mode(
+    provider: AnthropicProviderConfig,
+    model: str,
+    *,
+    thinking_level: ThinkingLevel | None = None,
+) -> str:
     compat = _model_compat(provider, model)
     if compat.get("forceAdaptiveThinking") is True:
+        if thinking_level is not None and normalize_thinking_level(thinking_level) == "off":
+            return "disabled"
         return "adaptive"
     return "budget"
 

tests/test_provider_catalog.py

@@ -102,6 +102,7 @@ def test_builtin_catalog_golden_anthropic_entry() -> None:
         "claude-opus-4-5-20251101",
         "claude-opus-4-6",
         "claude-opus-4-7",
+        "claude-opus-5",
         "claude-sonnet-4-5",
         "claude-sonnet-4-5-20250929",
         "claude-sonnet-4-6",
@@ -119,11 +120,21 @@ def test_builtin_catalog_golden_anthropic_entry() -> None:
         "claude-opus-4-5-20251101": 200_000,
         "claude-opus-4-6": 1_000_000,
         "claude-opus-4-7": 1_000_000,
+        "claude-opus-5": 1_000_000,
         "claude-sonnet-4-5": 200_000,
         "claude-sonnet-4-5-20250929": 200_000,
         "claude-sonnet-4-6": 1_000_000,
         "claude-sonnet-5": 1_000_000,
     }
+    opus_5 = entry.model_metadata["claude-opus-5"]
+    assert opus_5.context_window == 1_000_000
+    assert opus_5.max_tokens == 128_000
+    assert opus_5.input == ("text", "image")
+    assert opus_5.cost is not None
+    assert opus_5.cost["input"] == 5
+    assert opus_5.cost["output"] == 25
+    assert opus_5.compat == {"forceAdaptiveThinking": True}
+    assert opus_5.thinking_level_map == {"minimal": None, "xhigh": "max"}
     assert entry.thinking_levels == ("off", "minimal", "low", "medium", "high", "xhigh")
     assert entry.thinking_models == ()
     assert entry.thinking_default == "medium"

tests/test_provider_config.py

@@ -150,6 +150,13 @@ def test_builtin_openai_declares_model_scoped_thinking_capabilities() -> None:
         "medium",
         "high",
     )
+    assert provider_thinking_levels(anthropic, model="claude-opus-5") == (
+        "off",
+        "low",
+        "medium",
+        "high",
+        "xhigh",
+    )
 
 
 def test_load_provider_settings_accepts_provider_preferences_with_user_catalog(
@@ -931,6 +938,31 @@ def test_anthropic_config_from_provider_sets_thinking_budget(
     assert high_config.thinking_budget_tokens == 8192
 
 
+def test_anthropic_config_from_provider_maps_opus_5_adaptive_thinking(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv("ANTHROPIC_API_KEY", "test-key")
+    provider = ProviderSettings().get_provider("anthropic")
+    assert isinstance(provider, AnthropicProviderConfig)
+
+    off_config = anthropic_config_from_provider(
+        provider, model="claude-opus-5", thinking_level="off"
+    )
+    medium_config = anthropic_config_from_provider(
+        provider, model="claude-opus-5", thinking_level="medium"
+    )
+    xhigh_config = anthropic_config_from_provider(
+        provider, model="claude-opus-5", thinking_level="xhigh"
+    )
+
+    assert off_config.thinking_mode == "disabled"
+    assert off_config.thinking_effort is None
+    assert medium_config.thinking_mode == "adaptive"
+    assert medium_config.thinking_effort == "medium"
+    assert xhigh_config.thinking_mode == "adaptive"
+    assert xhigh_config.thinking_effort == "max"
+
+
 @pytest.mark.parametrize(
     ("parameter", "expected"),
     [

tests/test_tau_ai.py

@@ -1599,6 +1599,42 @@ def handler(request: httpx.Request) -> httpx.Response:
     assert payload["thinking"] == {"type": "enabled", "budget_tokens": 8192}
 
 
+@pytest.mark.anyio
+async def test_anthropic_provider_explicitly_disables_default_adaptive_thinking() -> None:
+    requests: list[httpx.Request] = []
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        requests.append(request)
+        return httpx.Response(
+            200,
+            text='data: {"type":"message_stop"}\n\n',
+            headers={"content-type": "text/event-stream"},
+        )
+
+    async with httpx.AsyncClient(transport=httpx.MockTransport(handler)) as client:
+        provider = AnthropicProvider(
+            AnthropicConfig(
+                api_key="test-key",
+                base_url="https://api.anthropic.test/v1",
+                thinking_mode="disabled",
+            ),
+            client=client,
+        )
+
+        await _collect(
+            provider.stream_response(
+                model="claude-opus-5",
+                system="You are Tau.",
+                messages=[UserMessage(content="Say hello")],
+                tools=[],
+            )
+        )
+
+    payload = loads(requests[0].content)
+    assert payload["thinking"] == {"type": "disabled"}
+    assert "output_config" not in payload
+
+
 @pytest.mark.anyio
 async def test_anthropic_provider_streams_thinking_deltas() -> None:
     def handler(_request: httpx.Request) -> httpx.Response:

website/content/guides/providers-and-models.md

@@ -181,6 +181,20 @@ list before creating or refreshing a runtime provider. This prevents accidental
 provider/model mismatches, such as trying to send an API-only OpenAI model to the
 separate `openai-codex` subscription provider.
 
+### Claude Opus 5
+
+Tau supports Anthropic's `claude-opus-5` through the direct `anthropic`
+provider. The model has a 1M-token context window, accepts text and images,
+generates up to 128k tokens, and costs $5 / $25 per million input/output tokens.
+Anthropic enables adaptive thinking by default. Tau maps its `low` through
+`high` modes directly, maps `xhigh` to Anthropic's maximum effort, and sends an
+explicit disabled-thinking request for `off`.
+
+Use `/login anthropic-api` or `/login anthropic-subscription`, then select
+**Claude Opus 5** in `/model`. See Anthropic's
+[Claude Opus 5 guide](https://platform.claude.com/docs/en/about-claude/models/whats-new-opus-5)
+for current behavior and availability.
+
 ## Adding a custom / local provider
 
 Any OpenAI-compatible endpoint works — including local servers like llama.cpp or