Python: Fix user agent prefix

[TaoChenOSU]

Motivation and Context

Automatically add user agent prefix according to the environment the code runs in.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[moonbox3]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/anthropic/agent_framework_anthropic
_bedrock_client.py	31	1	96%	153
_chat_client.py	438	34	92%	446, 449, 530, 623, 625, 768, 795–796, 874, 904–905, 950, 966–967, 974–976, 980–982, 986–989, 1103, 1113, 1165, 1313–1314, 1331, 1344, 1357, 1382–1383
_foundry_client.py	35	1	97%	153
_vertex_client.py	29	1	96%	146
packages/azure-ai-search/agent_framework_azure_ai_search
_context_provider.py	357	10	97%	120–121, 524, 575–576, 701–702, 880–881, 928
packages/azure-cosmos/agent_framework_azure_cosmos
_checkpoint_storage.py	135	1	99%	427
_history_provider.py	126	5	96%	163–165, 262, 269
packages/bedrock/agent_framework_bedrock
_chat_client.py	381	100	73%	298–299, 315–324, 329, 345–351, 354–355, 363, 380, 389, 400, 402, 404, 422–423, 444, 457, 469, 472, 480–481, 484–485, 487–488, 493–495, 497, 507–508, 530, 537, 546–547, 549–550, 552–554, 556, 558–559, 565–567, 570–571, 577–580, 586–596, 599, 618, 623, 665–666, 679, 705, 717, 722, 731, 735, 743–744, 748, 750–757
_embedding_client.py	80	13	83%	129–140, 152
packages/core/agent_framework
_telemetry.py	53	4	92%	78–80, 127
packages/foundry/agent_framework_foundry
_agent.py	147	36	75%	183–184, 188–190, 195–198, 293, 323–324, 336–337, 349–351, 353–354, 356–362, 364–365, 367, 369, 373–374, 561–562, 565, 607
_chat_client.py	152	19	87%	84, 86–88, 92–93, 97, 191, 222, 315, 376, 378, 476, 480–481, 483–486
_memory_provider.py	93	0	100%
packages/foundry_hosting/agent_framework_foundry_hosting
_invocations.py	32	24	25%	31, 33–34, 36–38, 42–43, 45–51, 53, 55, 57–60, 62, 68–69
_responses.py	432	140	67%	128–129, 138–139, 143, 148, 167, 195–197, 212–214, 225–227, 246–247, 249–251, 253–255, 259–262, 265–270, 277, 282, 285, 291–292, 294–295, 297, 299, 301–304, 306–308, 311, 315, 317–324, 327–328, 330–332, 340–345, 417–418, 523–524, 546, 810–812, 814, 832–861, 863, 881, 884, 919–923, 927–933, 940–944, 950–956, 963, 969, 972
packages/gemini/agent_framework_gemini
_chat_client.py	332	1	99%	375
packages/purview/agent_framework_purview
_client.py	128	2	98%	74–75
TOTAL	29087	3466	88%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
5805	30 💤	0 ❌	0 🔥	1m 36s ⏱️

[Copilot]

Pull request overview

Update Python connector/hosting packages to emit a User-Agent that can automatically include an environment-derived prefix (notably for Foundry hosted environments), so telemetry/SDK calls can be attributed correctly.

Changes:

• Introduce agent_framework._telemetry.get_user_agent() with hosted-environment detection and prefixing logic.
• Replace direct uses of AGENT_FRAMEWORK_USER_AGENT across multiple provider clients/tests with get_user_agent().
• Remove Foundry-hosting-specific user_agent_prefix(...) scoping in hosting servers in favor of automatic environment detection.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
python/packages/core/agent_framework/_telemetry.py	Adds hosted-environment detection and get_user_agent() prefix composition.
python/packages/core/tests/core/test_telemetry.py	Updates tests to cover new prefix registration + hosted detection paths.
python/packages/purview/agent_framework_purview/_client.py	Switches HTTP User-Agent header to get_user_agent().
python/packages/gemini/agent_framework_gemini/_chat_client.py	Switches Google client header to get_user_agent().
python/packages/bedrock/agent_framework_bedrock/_embedding_client.py	Switches boto user_agent_extra to get_user_agent().
python/packages/bedrock/agent_framework_bedrock/_chat_client.py	Switches boto user_agent_extra to get_user_agent().
python/packages/azure-cosmos/agent_framework_azure_cosmos/_history_provider.py	Switches Cosmos user_agent_suffix to get_user_agent().
python/packages/azure-cosmos/agent_framework_azure_cosmos/_checkpoint_storage.py	Switches Cosmos user_agent_suffix to get_user_agent().
python/packages/azure-ai-search/agent_framework_azure_ai_search/_context_provider.py	Switches Azure Search clients’ user_agent to get_user_agent().
python/packages/foundry/agent_framework_foundry/_memory_provider.py	Switches Foundry project client user_agent to get_user_agent().
python/packages/foundry/agent_framework_foundry/_chat_client.py	Switches Foundry project client user_agent to get_user_agent().
python/packages/foundry/agent_framework_foundry/_agent.py	Switches Foundry project client user_agent to get_user_agent().
python/packages/foundry/tests/foundry/test_foundry_memory_provider.py	Updates assertions to expect get_user_agent().
python/packages/foundry/tests/foundry/test_foundry_chat_client.py	Updates assertions to expect get_user_agent().
python/packages/foundry_hosting/agent_framework_foundry_hosting/_invocations.py	Removes per-request UA prefix context usage.
python/packages/foundry_hosting/agent_framework_foundry_hosting/_responses.py	Refactors handler flow and removes per-request UA prefix context usage.
python/packages/anthropic/agent_framework_anthropic/_vertex_client.py	Switches Anthropic client default headers to get_user_agent().
python/packages/anthropic/agent_framework_anthropic/_foundry_client.py	Switches Anthropic client default headers to get_user_agent().
python/packages/anthropic/agent_framework_anthropic/_bedrock_client.py	Switches Anthropic client default headers to get_user_agent().
python/packages/anthropic/agent_framework_anthropic/_chat_client.py	Switches extra headers/default headers to get_user_agent().
python/packages/anthropic/tests/test_anthropic_provider_clients.py	Updates test expectations to get_user_agent().

[github-actions]

Automated Code Review

Reviewers: 4 | Confidence: 89% | Result: All clear

Reviewed: Correctness, Security Reliability, Test Coverage, Design Approach

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Automated review by TaoChenOSU's agents

[Copilot]

Pull request overview

Copilot reviewed 21 out of 21 changed files in this pull request and generated 4 comments.

Comments suppressed due to low confidence (1)

python/packages/core/tests/core/test_telemetry.py:98

• These assertions expect the User-Agent to equal AGENT_FRAMEWORK_USER_AGENT, but get_user_agent() can now prepend a hosted prefix based on process environment (e.g., FOUNDRY_HOSTING_ENVIRONMENT). That makes this test suite environment-dependent. Patch/unset FOUNDRY_HOSTING_ENVIRONMENT (and reset _hosted_env_detected) in these tests before calling prepend_agent_framework_to_user_agent() to keep them deterministic.

def test_prepend_to_empty_headers():
    """Test prepending to headers without User-Agent."""
    headers = {"Content-Type": "application/json"}
    result = prepend_agent_framework_to_user_agent(headers)

    assert "User-Agent" in result
    assert result["User-Agent"] == AGENT_FRAMEWORK_USER_AGENT
    assert "Content-Type" in result


def test_prepend_to_empty_dict():
    """Test prepending to empty headers dict."""
    headers: dict[str, str] = {}
    result = prepend_agent_framework_to_user_agent(headers)

    assert "User-Agent" in result
    assert result["User-Agent"] == AGENT_FRAMEWORK_USER_AGENT

[github-actions]

Automated Code Review

Reviewers: 3 | Confidence: 88%

✓ Correctness

The PR replaces the static AGENT_FRAMEWORK_USER_AGENT constant with a dynamic get_user_agent() function that auto-detects hosted environments. The refactoring is clean and consistent across all client packages. One correctness issue: _detect_hosted_environment() catches ModuleNotFoundError from find_spec but not the broader ImportError that CPython's find_spec can raise when parent packages exist but a sub-package has broken imports. Since get_user_agent() is now called on the critical path (client init), an uncaught ImportError would prevent application startup.

✗ Security Reliability

The refactoring from ContextVar-based user_agent_prefix to global _user_agent_prefixes with lazy hosted-environment detection is generally sound. One reliability gap: importlib.util.find_spec can raise a bare ImportError (not just ModuleNotFoundError) when a parent package exists but fails to import (e.g., broken native extension). The current except clause only catches ModuleNotFoundError, so an ImportError would propagate through get_user_agent() and crash client initialization at every call site in this diff.

✗ Design Approach

I found two design-level problems. First, the telemetry change moves Foundry-hosting detection into the core agent_framework layer by probing hosting-specific environment and SDK state, which is a leaky abstraction and changes semantics from an explicit hosting-layer tag to an inferred process-wide tag. Second, _responses.py regresses cancellation handling: the new dispatcher returns inner streams without honoring cancellation_signal, so disconnected clients can still drive long-running agent/workflow work to completion.

Flagged Issues

• Response streaming in _handle_response no longer honors the provided cancellation_signal, so client disconnect or shutdown will continue consuming the underlying agent/workflow stream until completion, wasting resources.

Suggestions

• Widen the find_spec exception handler from ModuleNotFoundError to ImportError (its parent class, so both are caught): except (ImportError, ValueError):.
• Wrap the selected response stream with cancellation checks (or pass the signal through to the inner handlers) so hosting can stop work promptly when the request is cancelled.

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Automated review by TaoChenOSU's agents

[moonbox3]

Automated Code Review

Reviewers: 3 | Confidence: 85%

✓ Correctness

This PR replaces the per-request ContextVar-based user_agent_prefix context manager with a process-global set and lazy _detect_hosted_environment() detection, and updates all user-agent construction sites to call get_user_agent() instead of reading a static constant. The _handle_response change in _responses.py (from async generator to sync method returning AsyncIterable) is compatible with the framework's CreateHandlerFn type and _normalize_handler_result dispatch logic — the returned AsyncGenerator from _handle_workflow_agent/_handle_regular_agent correctly passes through the isinstance/iscoroutine/hasattr checks and is consumed as an AsyncIterator. The unresolved review comment about cancellation_signal being silently dropped remains active — both _handle_regular_agent and _handle_workflow_agent have had the parameter removed in this diff and the framework's orchestrator still passes the signal to the registered handler, but the handler no longer threads it through. No new correctness bugs were found beyond that pre-existing concern.

✗ Security Reliability

This PR replaces the per-request ContextVar-based user_agent_prefix mechanism with a process-global mutable set detected lazily at startup, and removes the user_agent_prefix context-manager from the hosting layers. Two reliability issues warrant attention: (1) the unresolved carry-over concern that cancellation_signal is silently dropped in _handle_response — it is accepted in the signature but never forwarded to either inner handler — meaning client disconnects and server shutdowns will not stop the agent stream; (2) the new global _user_agent_prefixes: set[str] is mutated via _add_user_agent_prefix while concurrently iterated by sorted(_user_agent_prefixes) in get_user_agent(), which can raise RuntimeError: Set changed size during iteration in multi-threaded server scenarios (this was the subject of a previously-resolved review comment that is reintroduced by this diff).

✗ Test Coverage

The new _detect_hosted_environment tests are well-structured and cover the main paths, but test_detect_hosted_fallback_import_error is environment-dependent: it patches builtins.__import__ without also mocking importlib.util.find_spec, so in environments without azure.ai.agentserver.core installed the function exits early and the except (ImportError, AttributeError) branch is never reached. Additionally, the foundry-package assertions use get_user_agent() on both sides of the equality check, which means they cannot catch a regression to the static AGENT_FRAMEWORK_USER_AGENT constant in non-hosted environments.

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Automated review by moonbox3's agents