Python: support current FastAPI releases

[Eduard van Valkenburg (eavanvalkenburg)]

Motivation & Context

Current FastAPI releases cannot be installed with agent-framework-ag-ui because its upper bound excludes FastAPI 0.140 and 0.141. Related package and sample constraints retain an even older ceiling, which can also force consumers onto outdated FastAPI releases.

Description & Review Guide

• What are the major changes? Raise the FastAPI upper bound to <0.142.0 in AG-UI, DevUI, hosting-responses, and the affected hosting samples. Refresh uv.lock with uv lock --upgrade-package fastapi, updating only FastAPI from 0.138.0 to 0.141.1.
• What is the impact of these changes? Consumers can resolve the current FastAPI release while existing supported lower bounds remain unchanged.
• What do you want reviewers to focus on? Confirm the FastAPI range is consistent across package metadata, sample metadata, and the lockfile.

Related Issue

Fixes #8042

Contribution Checklist

• The code builds clean without any errors or warnings
• All unit tests pass, and I have added new tests where possible
• The PR follows the Contribution Guidelines
• This PR is linked to an issue and there is no other open PR for this issue (see Related Issue above).
• This is not a breaking change. If it is breaking, add the breaking change label or put [BREAKING] in the title prefix.

[Copilot]

🟢 Approval recommended

The dependency updates are consistent, and no unresolved issues were identified.

Pull request overview

Updates Python dependencies to support FastAPI 0.141.x while preserving existing lower bounds.

Changes:

• Raises FastAPI upper bounds to <0.142.0.
• Updates the lockfile to FastAPI 0.141.1.
• Aligns package and sample constraints.

File summaries

File	Description
python/uv.lock	Locks FastAPI 0.141.1 and updates constraints.
python/samples/04-hosting/af-hosting/local_telegram/pyproject.toml	Updates the sample dependency range.
python/samples/04-hosting/af-hosting/local_telegram/app.py	Synchronizes inline dependency metadata.
python/samples/04-hosting/af-hosting/local_responses/pyproject.toml	Updates the sample dependency range.
python/samples/04-hosting/af-hosting/local_responses_workflow/pyproject.toml	Updates the workflow sample dependency range.
python/samples/04-hosting/af-hosting/local_responses_harness/pyproject.toml	Updates the harness sample dependency range.
python/packages/hosting-responses/pyproject.toml	Expands FastAPI test compatibility.
python/packages/devui/pyproject.toml	Expands FastAPI compatibility.
python/packages/ag-ui/pyproject.toml	Expands FastAPI compatibility.

Review details

• Files reviewed: 8/9 changed files
• Comments generated: 0
• Review effort level: Balanced

---

💡 Add a code-review agent skill for context-aware, tailored reviews. Learn more in the docs.

[github-actions]

MAF Automated Review — Iteration 1

Result: No findings
Scope: full PR (1 commit(s)): e819438eedfd
Model: gpt-5.6-sol-fast

Overview

The PR consistently raises the FastAPI upper bound to exclude 0.142 while permitting validated 0.140 and 0.141 releases, and refreshes the generated lockfile to FastAPI 0.141.1 without changing runtime code. Matching manifest and lock metadata, successful lock validation, affected-package compatibility coverage, and unchanged state-management behavior provide strong guardrails. No publishable Critical, High, or Medium risk was established.

Reviewed the supplied pull-request change set across correctness, security/reliability, architecture, and failure behavior.
No publishable findings remained after source verification for this scope.