feat(model-routing): add ModelRouter core and candidate resolution

site/src/content/changelog/harness/python-v1.50.0.md

@@ -0,0 +1,32 @@
+---
+sdk: harness
+language: python
+version: "1.50.0"
+tag: python/v1.50.0
+date: 2026-07-24
+releaseUrl: https://github.com/strands-agents/harness-sdk/releases/tag/python/v1.50.0
+packageUrl: https://pypi.org/project/strands-agents/1.50.0/
+entries:
+  - { type: chore, breaking: false, scope: null, areas: [mcp, community], title: "merge strands-agents/mcp-server into monorepo", pr: 3300, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3300", commit: "7acaca8", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/7acaca8", author: zastrowm }
+  - { type: fix, breaking: false, scope: ci, areas: [community], title: "make the release pip-audit step actually run", pr: 3335, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3335", commit: "54124de", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/54124de", author: pgrayy }
+  - { type: docs, breaking: false, scope: site, areas: [], title: "replace duplicated examples guide with reference pointer", pr: 3288, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3288", commit: "41f9f59", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/41f9f59", author: yonib05 }
+  - { type: other, breaking: false, scope: typescript, areas: [community], title: "bump brace-expansion from 5.0.6 to 5.0.7", pr: 3370, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3370", commit: "1b5fddb", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/1b5fddb", author: "dependabot[bot]" }
+  - { type: refactor, breaking: false, scope: memory, areas: [], title: "refactor TestMemoryStore to use the unified storage interface", pr: 3260, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3260", commit: "41ccf5e", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/41ccf5e", author: opieter-aws }
+  - { type: feat, breaking: false, scope: middleware, areas: [hooks, tool], title: "add ExecuteToolStage with middleware-initiated interrupts", pr: 3233, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3233", commit: "50d76c3", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/50d76c3", author: zastrowm }
+  - { type: other, breaking: false, scope: typescript, areas: [community], title: "bump body-parser from 2.2.2 to 2.3.0", pr: 3387, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3387", commit: "8685e1a", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/8685e1a", author: "dependabot[bot]" }
+  - { type: fix, breaking: false, scope: openai, areas: [devx, model], title: "replay assistant text history as valid string-content input in Responses adapters", pr: 3399, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3399", commit: "6d1eda9", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/6d1eda9", author: agent-of-mkmeral }
+  - { type: other, breaking: false, scope: null, areas: [community], title: "bump actions/setup-python from 6 to 7", pr: 3352, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3352", commit: "c6e8b96", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/c6e8b96", author: "dependabot[bot]" }
+  - { type: feat, breaking: false, scope: py, areas: [devx, agent], title: "configurable retry exceptions (#1597)", pr: 3340, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3340", commit: "50d388e", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/50d388e", author: crazybolillo }
+  - { type: fix, breaking: false, scope: graph, areas: [multiagent], title: "keep fan-in node out of resume while a parallel sibling is in-flight", pr: 3390, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3390", commit: "b0ff5ef", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/b0ff5ef", author: opieter-aws }
+  - { type: other, breaking: false, scope: null, areas: [community], title: "bump astral-sh/setup-uv from 8.3.0 to 9.0.0", pr: 3407, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3407", commit: "ba297cf", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/ba297cf", author: "dependabot[bot]" }
+  - { type: feat, breaking: false, scope: bidi, areas: [bidirectional-streaming], title: "propose bidi webrtc design", pr: 3386, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3386", commit: "b7529d2", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/b7529d2", author: mehtarac }
+  - { type: other, breaking: false, scope: null, areas: [community], title: "bump pypa/gh-action-pypi-publish from 1.14.0 to 1.14.1", pr: 3406, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3406", commit: "7b0717c", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/7b0717c", author: "dependabot[bot]" }
+  - { type: fix, breaking: false, scope: null, areas: [persistence], title: "reject keys for s3 storage if not configured", pr: 3411, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3411", commit: "33f5f74", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/33f5f74", author: opieter-aws }
+  - { type: fix, breaking: false, scope: null, areas: [community], title: "verify aws region", pr: 3412, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3412", commit: "81bccd8", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/81bccd8", author: opieter-aws }
+  - { type: feat, breaking: false, scope: vended-tools, areas: [tool], title: "add http_request to strands-py", pr: 3395, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3395", commit: "18484f2", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/18484f2", author: chaynabors }
+  - { type: fix, breaking: false, scope: models/llamacpp, areas: [model], title: "send llama.cpp sampler params at the top level, not under extra_body", pr: 3423, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3423", commit: "9c077c4", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/9c077c4", author: ebarkhordar }
+  - { type: feat, breaking: false, scope: vended-tools, areas: [tool, agent], title: "add stop tool", pr: 3397, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3397", commit: "767b801", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/767b801", author: chaynabors }
+  - { type: fix, breaking: false, scope: multiagent, areas: [context, multiagent], title: "preserve shared context and cumulative accounting across serialize/deserialize", pr: 3396, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3396", commit: "ba37a27", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/ba37a27", author: opieter-aws }
+  - { type: feat, breaking: false, scope: vended-tools, areas: [tool], title: "add sleep tool", pr: 3393, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3393", commit: "d9f9314", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/d9f9314", author: chaynabors }
+  - { type: fix, breaking: false, scope: python, areas: [model], title: "surface Responses stream failures", pr: 3427, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3427", commit: "e03f864", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/e03f864", author: strandly-the-agent }
+---

site/src/content/changelog/harness/typescript-v1.11.0.md

@@ -0,0 +1,29 @@
+---
+sdk: harness
+language: typescript
+version: "1.11.0"
+tag: typescript/v1.11.0
+date: 2026-07-24
+releaseUrl: https://github.com/strands-agents/harness-sdk/releases/tag/typescript/v1.11.0
+packageUrl: https://www.npmjs.com/package/@strands-agents/sdk/v/1.11.0
+entries:
+  - { type: chore, breaking: false, scope: null, areas: [mcp, community], title: "merge strands-agents/mcp-server into monorepo", pr: 3300, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3300", commit: "7acaca8", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/7acaca8", author: zastrowm }
+  - { type: fix, breaking: false, scope: ci, areas: [community], title: "make the release pip-audit step actually run", pr: 3335, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3335", commit: "54124de", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/54124de", author: pgrayy }
+  - { type: refactor, breaking: false, scope: ts, areas: [devx], title: "extract shared registerNodeDefaults() to prevent src/test drift", pr: 3303, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3303", commit: "961b1b6", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/961b1b6", author: gautamsirdeshmukh }
+  - { type: fix, breaking: false, scope: vercel, areas: [model], title: "detect tool use from streamed content when finish_reason is non-tool", pr: 3206, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3206", commit: "d2fc508", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/d2fc508", author: maxmilian }
+  - { type: docs, breaking: false, scope: site, areas: [], title: "replace duplicated examples guide with reference pointer", pr: 3288, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3288", commit: "41f9f59", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/41f9f59", author: yonib05 }
+  - { type: fix, breaking: false, scope: openai, areas: [model], title: "surface Responses stream failures", pr: 3290, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3290", commit: "3c234b2", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/3c234b2", author: didhd }
+  - { type: other, breaking: false, scope: typescript, areas: [community], title: "bump brace-expansion from 5.0.6 to 5.0.7", pr: 3370, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3370", commit: "1b5fddb", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/1b5fddb", author: "dependabot[bot]" }
+  - { type: refactor, breaking: false, scope: memory, areas: [], title: "refactor TestMemoryStore to use the unified storage interface", pr: 3260, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3260", commit: "41ccf5e", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/41ccf5e", author: opieter-aws }
+  - { type: feat, breaking: false, scope: ts, areas: [language, tool], title: "add ToolExecutor class hierarchy", pr: 3268, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3268", commit: "a3f54c8", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/a3f54c8", author: gautamsirdeshmukh }
+  - { type: other, breaking: false, scope: typescript, areas: [community], title: "bump body-parser from 2.2.2 to 2.3.0", pr: 3387, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3387", commit: "8685e1a", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/8685e1a", author: "dependabot[bot]" }
+  - { type: fix, breaking: false, scope: openai, areas: [devx, model], title: "replay assistant text history as valid string-content input in Responses adapters", pr: 3399, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3399", commit: "6d1eda9", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/6d1eda9", author: agent-of-mkmeral }
+  - { type: other, breaking: false, scope: null, areas: [community], title: "bump actions/setup-python from 6 to 7", pr: 3352, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3352", commit: "c6e8b96", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/c6e8b96", author: "dependabot[bot]" }
+  - { type: other, breaking: false, scope: null, areas: [community], title: "bump astral-sh/setup-uv from 8.3.0 to 9.0.0", pr: 3407, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3407", commit: "ba297cf", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/ba297cf", author: "dependabot[bot]" }
+  - { type: feat, breaking: false, scope: bidi, areas: [bidirectional-streaming], title: "propose bidi webrtc design", pr: 3386, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3386", commit: "b7529d2", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/b7529d2", author: mehtarac }
+  - { type: other, breaking: false, scope: null, areas: [community], title: "bump pypa/gh-action-pypi-publish from 1.14.0 to 1.14.1", pr: 3406, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3406", commit: "7b0717c", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/7b0717c", author: "dependabot[bot]" }
+  - { type: fix, breaking: false, scope: null, areas: [persistence], title: "reject keys for s3 storage if not configured", pr: 3411, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3411", commit: "33f5f74", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/33f5f74", author: opieter-aws }
+  - { type: fix, breaking: false, scope: null, areas: [community], title: "verify aws region", pr: 3412, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3412", commit: "81bccd8", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/81bccd8", author: opieter-aws }
+  - { type: feat, breaking: false, scope: vended-tools, areas: [tool, agent], title: "add stop tool", pr: 3397, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3397", commit: "767b801", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/767b801", author: chaynabors }
+  - { type: feat, breaking: false, scope: vended-tools, areas: [tool], title: "add sleep tool", pr: 3393, prUrl: "https://github.com/strands-agents/harness-sdk/pull/3393", commit: "d9f9314", commitUrl: "https://github.com/strands-agents/harness-sdk/commit/d9f9314", author: chaynabors }
+---

site/src/content/docs/user-guide/concepts/tools/vended-tools-imports.ts

@@ -48,5 +48,5 @@ import { makeSleep } from '@strands-agents/sdk/vended-tools/sleep'
 
 // --8<-- [start:stop_import]
 import { Agent } from '@strands-agents/sdk'
-import { stop } from '@strands-agents/sdk/vended-tools/stop'
+import { stop } from '@strands-agents/sdk/experimental/vended-tools/stop'
 // --8<-- [end:stop_import]

site/src/content/docs/user-guide/concepts/tools/vended-tools.mdx

@@ -11,10 +11,10 @@ sourceLinks:
   - path: strands-ts/src/vended-tools/http-request/http-request.ts
   - path: strands-ts/src/vended-tools/notebook/notebook.ts
   - path: strands-ts/src/vended-tools/sleep/sleep.ts
-  - path: strands-ts/src/vended-tools/stop/stop.ts
+  - path: strands-ts/src/experimental/vended-tools/stop/stop.ts
   - path: strands-py/src/strands/vended_tools/http_request/http_request.py
   - path: strands-py/src/strands/vended_tools/sleep/sleep.py
-  - path: strands-py/src/strands/vended_tools/stop/stop.py
+  - path: strands-py/src/strands/experimental/tools/stop/stop.py
 ---
 
 Vended tools are pre-built tools included directly in the Strands SDK for common agent tasks like file operations, shell commands, HTTP requests, and persistent notes. 
@@ -40,7 +40,7 @@ Each tool is imported from its own subpath under `@strands-agents/sdk/vended-too
 | [Notebook](#notebook) | Manage persistent text notebooks | TypeScript (Node.js, browsers) |
 | [Bash](#bash) | Execute shell commands with persistent sessions | Python, TypeScript (Node.js, Unix/Linux/macOS) |
 | [Sleep](#sleep) | Pause execution for a bounded, cancellable duration | Python, TypeScript (Node.js, browsers) |
-| [Stop](#stop) | Gracefully end the agent loop when the task is complete | Python, TypeScript (Node.js, browsers) |
+| [Stop](#stop-experimental) | Gracefully end the agent loop when the task is complete | Python, TypeScript (Node.js, browsers) |
 
 ### File Editor
 
@@ -269,7 +269,10 @@ agent = Agent(tools=[short_sleep])
 
 ---
 
-### Stop
+### Stop (Experimental)
+
+> This tool is experimental and subject to change in future
+> revisions without notice.
 
 Lets the model gracefully end the agent loop with an optional final message. The default loop already terminates when the model returns without any tool call; the stop tool is useful when you want an explicit "I am done" affordance, when a workflow enforces that termination is a deliberate model decision, or when a sub-agent needs to signal completion back to a coordinator via the loop's last assistant message.
 
@@ -295,7 +298,7 @@ The two SDKs shim onto different loop-termination primitives, which produces a s
 
 ```python
 from strands import Agent
-from strands.vended_tools import stop
+from strands.experimental.tools import stop
 
 agent = Agent(
     tools=[stop],
@@ -307,7 +310,7 @@ result = agent("Summarize the changes in ./CHANGELOG.md")
 </Tab>
 </Tabs>
 
-📖 [Full API Reference](https://github.com/strands-agents/harness-sdk/blob/main/strands-ts/src/vended-tools/stop/README.md)
+📖 [Full API Reference](https://github.com/strands-agents/harness-sdk/blob/main/strands-ts/src/experimental/vended-tools/stop/README.md)
 
 ---
 

site/src/content/docs/user-guide/concepts/tools/vended-tools.ts

@@ -7,7 +7,7 @@ import { notebook } from '@strands-agents/sdk/vended-tools/notebook'
 // --8<-- [end:basic_import]
 import { SessionManager, FileStorage } from '@strands-agents/sdk'
 import { sleep, makeSleep } from '@strands-agents/sdk/vended-tools/sleep'
-import { stop } from '@strands-agents/sdk/vended-tools/stop'
+import { stop } from '@strands-agents/sdk/experimental/vended-tools/stop'
 
 // Agent with vended tools example
 async function agentWithVendedToolsExample() {

strands-py/src/strands/_context_manager/modes/agentic/agentic_context.py

@@ -8,7 +8,7 @@
 
 import logging
 from dataclasses import replace
-from typing import TYPE_CHECKING, Literal
+from typing import Literal
 
 from ...._middleware.stages import InvokeModelContext
 from ...._middleware.types import MiddlewareInputHandler
@@ -26,9 +26,6 @@
 from ....types.exceptions import ContextWindowOverflowException
 from ....types.tools import ToolContext
 
-if TYPE_CHECKING:
-    from ....models.model import Model
-
 logger = logging.getLogger(__name__)
 
 # Default number of recent messages to preserve verbatim during summarization or truncation.
@@ -286,15 +283,13 @@ def _matches_pin_filter(message: Message, filter: Literal["user", "assistant", "
     return True  # type: ignore[unreachable]
 
 
-def create_token_usage_middleware(model: "Model") -> MiddlewareInputHandler:
+def create_token_usage_middleware() -> MiddlewareInputHandler:
     """Create middleware that appends a ``<context-status>`` block to the last message.
 
-    The block reports projected input-token usage against the model's context window limit so the
-    model can decide when to compress. The original messages are not mutated; the last message is
-    copied and the status text appended to the copy.
-
-    Args:
-        model: The model whose context window limit is reported.
+    The block reports projected input-token usage against the context window limit of the
+    model that will actually handle the call (``context.model``), so guidance stays correct
+    even when middleware has redirected the call to a different model. The original messages
+    are not mutated; the last message is copied and the status text appended to the copy.
 
     Returns:
         An async ``MiddlewareInputHandler`` for the ``InvokeModelStage.Input`` phase.
@@ -305,7 +300,7 @@ async def middleware(context: InvokeModelContext) -> InvokeModelContext:
         if projected_input_tokens is None:
             return context
 
-        context_window_limit = model.context_window_limit or DEFAULT_CONTEXT_WINDOW_LIMIT
+        context_window_limit = context.model.context_window_limit or DEFAULT_CONTEXT_WINDOW_LIMIT
         remaining = max(0, context_window_limit - projected_input_tokens)
         percent_used = (projected_input_tokens / context_window_limit) * 100