[ML-59256] Add MCP approval/response classes by kevin-wangg · Pull Request #18815 · mlflow/mlflow

kevin-wangg · 2025-11-12T21:52:25Z

🛠 DevTools 🛠

Install mlflow from this PR

# mlflow
pip install git+https://github.com/mlflow/mlflow.git@refs/pull/18815/merge
# mlflow-skinny
pip install git+https://github.com/mlflow/mlflow.git@refs/pull/18815/merge#subdirectory=libs/skinny

For Databricks, use the following command:

%sh curl -LsSf https://raw.githubusercontent.com/mlflow/mlflow/HEAD/dev/install-skinny.sh | sh -s pull/18815/merge

Related Issues/PRs

#xxx

What changes are proposed in this pull request?

This PR adds MCP approval and response classes to MLflow

How is this PR tested?

Existing unit/integration tests
New unit/integration tests
Manual tests

Manually tested with a MAS agent:
Sent the following request that should trigger a tool call

curl --location 'https://eng-ml-agent-bricks-us-east-1.staging.cloud.databricks.com/serving-endpoints/mas-d477f72c-endpoint/invocations' \
--header 'x-databricks-traffic-id: testenv://liteswap/kevin-mas' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer dapi4d06921b973e659b423567eb349e39ff' \
--data '{
    "input": [
        {
            "role": "user",
            "content": "what'\''s 123 x 100"
        },
        {
            "type": "message",
            "id": "run--db6f9559-40e1-4f26-b5c8-3b824d025827",
            "content": [
                {
                    "type": "output_text",
                    "text": "I'\''ll calculate 123 x 100 for you using Python.",
                    "annotations": []
                }
            ],
            "role": "assistant"
        }
    ],
    "databricks_options": {
        "return_trace": true
    },
    "stream": true
}'

Received the following

{
    "type": "response.output_item.done",
    "custom_outputs": null,
    "item": {
        "type": "mcp_approval_request",
        "id": "1da9fbd1-1db2-4b32-a464-e09b613975b5",
        "arguments":"{\"code\": \"result = 123 * 100\\nprint(f\\\"123 \× 100 = {result}\\\")\"}",
        "name": "system__ai__python_exec",
        "server_label": "server_label"
    }
}

Appended the mcp approval request and mcp approval response to the messages, and then sent it back

curl --location 'https://eng-ml-agent-bricks-us-east-1.staging.cloud.databricks.com/serving-endpoints/mas-d477f72c-endpoint/invocations' \
--header 'x-databricks-traffic-id: testenv://liteswap/kevin-mas' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer dapi4d06921b973e659b423567eb349e39ff' \
--data '{
    "input": [
        {
            "role": "user",
            "content": "what'\''s 123 x 100"
        },
        {
            "type": "message",
            "id": "run--db6f9559-40e1-4f26-b5c8-3b824d025827",
            "content": [
                {
                    "type": "output_text",
                    "text": "I'\''ll calculate 123 x 100 for you using Python.",
                    "annotations": []
                }
            ],
            "role": "assistant"
        },
        {
            "type": "mcp_approval_request",
            "id": "1234",
            "name": "system__ai__python_exec",
            "arguments": "{\"code\": \"result = 123 * 100\\nprint(f\\\"123 x 100 = {result}\\\")\"}",
            "server_label": "server_label"
        },
        {
            "type": "mcp_approval_response",
            "id": "5678",
            "approval_request_id": "1234",
            "approve": true,
            "reason": "approved"
        } 
    ],
    "databricks_options": {
        "return_trace": true
    },
    "stream": true
}'

Received the following stream back

If the MCP approval was denied, then nothing comes back.

curl --location 'https://eng-ml-agent-bricks-us-east-1.staging.cloud.databricks.com/serving-endpoints/mas-d477f72c-endpoint/invocations' \
--header 'x-databricks-traffic-id: testenv://liteswap/kevin-mas' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer dapi4d06921b973e659b423567eb349e39ff' \
--data '{
    "input": [
        {
            "role": "user",
            "content": "what'\''s 123 x 100"
        },
        {
            "type": "message",
            "id": "run--db6f9559-40e1-4f26-b5c8-3b824d025827",
            "content": [
                {
                    "type": "output_text",
                    "text": "I'\''ll calculate 123 x 100 for you using Python.",
                    "annotations": []
                }
            ],
            "role": "assistant"
        },
        {
            "type": "mcp_approval_request",
            "id": "1234",
            "name": "system__ai__python_exec",
            "arguments": "{\"code\": \"result = 123 * 100\\nprint(f\\\"123 x 100 = {result}\\\")\"}",
            "server_label": "server_label"
        },
        {
            "type": "mcp_approval_response",
            "id": "5678",
            "approval_request_id": "1234",
            "approve": false,
            "reason": "disapproved"
        }  
    ],
    "databricks_options": {
        "return_trace": true
    },
    "stream": true
}'

Receive back

Does this PR require documentation update?

Release Notes

Is this a user-facing change?

No. You can skip the rest of this section.
Yes. Give a description of this change to be included in the release notes for MLflow users.

What component(s), interfaces, languages, and integrations does this PR affect?

Components

How should the PR be classified in the release notes? Choose one:

rn/none - No description will be included. The PR will be mentioned only by the PR number in the "Small Bugfixes and Documentation Updates" section
rn/breaking-change - The PR will be mentioned in the "Breaking Changes" section
rn/feature - A new user-facing feature worth mentioning in the release notes
rn/bug-fix - A user-facing bug fix worth mentioning in the release notes
rn/documentation - A user-facing documentation change worth mentioning in the release notes

Should this PR be included in the next patch release?

Yes should be selected for bug fixes, documentation updates, and other small changes. No should be selected for new features and larger changes. If you're unsure about the release classification of this PR, leave this unchecked to let the maintainers decide.

What is a minor/patch release?

Minor release: a release that increments the second part of the version number (e.g., 1.2.0 -> 1.3.0).
Bug fixes, doc updates and new features usually go into minor releases.
Patch release: a release that increments the third part of the version number (e.g., 1.2.0 -> 1.2.1).
Bug fixes and doc updates usually go into patch releases.

Yes (this PR will be cherry-picked and included in the next patch release)
No (this PR will be included in the next minor release)

github-actions · 2025-11-12T21:52:39Z

@kevin-wangg Thank you for the contribution! Could you fix the following issue(s)?

⚠ DCO check

The DCO check failed. Please sign off your commit(s) by following the instructions here. See https://github.com/mlflow/mlflow/blob/master/CONTRIBUTING.md#sign-your-work for more details.

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

mlflow/types/responses_helpers.py

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

…mlflow into add-tool-confirmation-types

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

…mlflow into add-tool-confirmation-types

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

…cessing (mlflow#18898) Signed-off-by: Avesh Singh <aveshcsingh@gmail.com> Co-authored-by: Xiang Shen <xshen.shc@gmail.com> Co-authored-by: Claude <noreply@anthropic.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

…18937) Signed-off-by: Kevin Lin <kevin.lin@databricks.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Signed-off-by: joelrobin18 <joelrobin1818@gmail.com> Co-authored-by: Yuki Watanabe <31463517+B-Step62@users.noreply.github.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

…8948) Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: harupy <17039389+harupy@users.noreply.github.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

mlflow/pyfunc/model.py

docs/api_reference/api_inventory.txt

bbqiu

changes LGTM - please wait on merging until you have had a chance to test it w/ an agent manually?

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

mlflow/pyfunc/model.py

docs/docs/genai/flavors/responses-agent-intro.mdx

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

…mlflow into add-tool-confirmation-types

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

serena-ruan

LGTM! @bbqiu could we file a follow-up PR to clean up the static methods in ResponsesAgent?

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

github-actions · 2025-11-26T01:18:00Z

Documentation preview for 3793317 is available at:

https://pr-18815--mlflow-docs-preview.netlify.app/docs/latest/

Changed Pages (1)

genai/flavors/responses-agent-intro (modified)

More info

Ignore this comment if this PR does not change the documentation.
The preview is updated when a new commit is pushed to this PR.
This comment was created by this workflow run.
The documentation was built by this workflow run.

kevin-wangg added 4 commits November 12, 2025 14:18

Add MCP approval/response classes

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Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Formatting

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Formatting

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Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Formatting

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kevin-wangg force-pushed the add-tool-confirmation-types branch from 40b3d2e to 09095f2 Compare November 12, 2025 22:18

Merge branch 'mlflow:master' into add-tool-confirmation-types

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bbqiu reviewed Nov 13, 2025

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kevin-wangg added 2 commits November 13, 2025 12:12

Add helpers for new types

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Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Merge branch 'add-tool-confirmation-types' of github.com:kevin-wangg/…

750a91a

…mlflow into add-tool-confirmation-types

kevin-wangg changed the title ~~Add MCP approval/response classes~~ [ML-59256] Add MCP approval/response classes Nov 13, 2025

kevin-wangg added 6 commits November 13, 2025 13:59

Add cases in response_to_cc

cf7e6c2

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Update test cases

c2f936f

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Merge branch 'mlflow:master' into add-tool-confirmation-types

e740ee9

Merge branch 'master' into add-tool-confirmation-types

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Merge branch 'add-tool-confirmation-types' of github.com:kevin-wangg/…

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…mlflow into add-tool-confirmation-types

Formatting

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Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

kevin-wangg force-pushed the add-tool-confirmation-types branch from a471b9b to 66a7267 Compare November 20, 2025 22:40

github-actions bot added v3.6.1 rn/none List under Small Changes in Changelogs. area/models MLmodel format, model serialization/deserialization, flavors labels Nov 20, 2025

kevin-wangg and others added 7 commits November 21, 2025 01:30

Update tests

74ce083

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

[Doc] Improve readablity by adjusting sidebar layout & style (mlflow#…

53d2ce3

…18937) Signed-off-by: Kevin Lin <kevin.lin@databricks.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Migrate Python job in master.yml workflow to uv (mlflow#18934)

2bd906a

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Pydantic AI Chat UI (mlflow#18777)

12d27ed

Signed-off-by: joelrobin18 <joelrobin1818@gmail.com> Co-authored-by: Yuki Watanabe <31463517+B-Step62@users.noreply.github.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Sort documentation pages alphabetically in preview comments (mlflow#1…

24b30c6

…8948) Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: harupy <17039389+harupy@users.noreply.github.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Improve docs clear command to remove ignored files (mlflow#18949)

b4c4562

Signed-off-by: harupy <17039389+harupy@users.noreply.github.com> Co-authored-by: Claude <noreply@anthropic.com> Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

kevin-wangg force-pushed the add-tool-confirmation-types branch from 1ed3fa7 to b4c4562 Compare November 21, 2025 09:30

Merge branch 'master' into add-tool-confirmation-types

afb31b7

kevin-wangg added 8 commits November 21, 2025 13:29

Update docs

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Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Update docs

95fd2d8

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Merge branch 'master' into add-tool-confirmation-types

265223e

Add static methods

d6623ea

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Merge branch 'mlflow:master' into add-tool-confirmation-types

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Add to api inventory

9765cbe

Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Update role

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Update unit tests

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bbqiu reviewed Nov 24, 2025

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kevin-wangg added 3 commits November 24, 2025 15:56

Update roles

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Signed-off-by: Kevin Wang <kevinwang2040@gmail.com>

Update roles

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Update api inventory

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kevin-wangg added 4 commits November 25, 2025 10:27

Remove static methods

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Reorder imports

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Rename paths

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Merge branch 'mlflow:master' into add-tool-confirmation-types

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kevin-wangg requested a review from serena-ruan November 25, 2025 18:33

kevin-wangg added 3 commits November 25, 2025 15:52

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Merge branch 'add-tool-confirmation-types' of github.com:kevin-wangg/…

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serena-ruan approved these changes Nov 26, 2025

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kevin-wangg added 2 commits November 25, 2025 17:07

Update docs

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Merge branch 'master' into add-tool-confirmation-types

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Merge branch 'master' into add-tool-confirmation-types

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serena-ruan merged commit 78fb007 into mlflow:master Nov 26, 2025
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[ML-59256] Add MCP approval/response classes#18815

[ML-59256] Add MCP approval/response classes#18815
serena-ruan merged 43 commits intomlflow:masterfrom
kevin-wangg:add-tool-confirmation-types

kevin-wangg commented Nov 12, 2025 •

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Related Issues/PRs

What changes are proposed in this pull request?

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