Add support for Python 3.15

[Kludex]

Add Python 3.15 to the Linux and Windows test matrix and the mcp and mcp-types classifiers. Update CI's test-job uv and the lockfile, require compatible dependency versions only on Python 3.15, and adapt the BlockBuster fixture to its available checks.

Validation: full tests, 100% branch coverage, and strict-no-cover on Python 3.15.0rc3 with locked and lowest-direct dependencies, plus Python 3.10 with locked dependencies. Ruff and pyright with the Linux target pass; Windows runs in CI.

AI Disclaimer

This PR was developed with the assistance of either Claude or Codex. I've reviewed and verified the changes.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-12T11:42:50.930200Z	830b55e	PR opened

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[github-actions]

📚 Documentation preview

Preview	https://pr-3688.mcp-python-docs.pages.dev
Deployment	https://dc693db6.mcp-python-docs.pages.dev
Commit	64ce058
Triggered by	@Kludex
Updated	2026-10-12 11:45:59 UTC

[cubic-dev-ai]

1 issue found and verified against the latest diff

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="pyproject.toml">

<violation number="1" location="pyproject.toml:139">
P2: The frozen lock routes Python 3.15.0rc3 through the `<3.15` branch and installs Pydantic 2.12.5, despite this marker requiring 2.14.0. Use a prerelease-aware full-version cutoff in the conditional requirements and regenerate the lock.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>

[cubic-dev-ai]

P2: The frozen lock routes Python 3.15.0rc3 through the <3.15 branch and installs Pydantic 2.12.5, despite this marker requiring 2.14.0. Use a prerelease-aware full-version cutoff in the conditional requirements and regenerate the lock.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. At pyproject.toml, line 139:

<comment>The frozen lock routes Python 3.15.0rc3 through the `<3.15` branch and installs Pydantic 2.12.5, despite this marker requiring 2.14.0. Use a prerelease-aware full-version cutoff in the conditional requirements and regenerate the lock.</comment>

<file context>
@@ -133,14 +136,16 @@ dependencies = [
     "httpx2>=2.10.0",
     "mcp-types=={{ version }}",
-    "pydantic>=2.12.0",
+    "pydantic>=2.14.0; python_version >= '3.15'",
+    "pydantic>=2.12.0; python_version < '3.15'",
     "starlette>=0.48.0; python_version >= '3.14'",
</file context>

[cubic-dev-ai]

1 issue found across 5 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name=".github/workflows/shared.yml">

<violation number="1" location=".github/workflows/shared.yml:75">
P1: The lockfile now uses revision 5, but the other jobs in this workflow still install uv 0.9.5 and run frozen syncs; those jobs will fail to read it. Upgrade the remaining lockfile-consuming jobs to a uv version that supports this revision.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

Turn on auto-fix | Re-trigger cubic</sub>

[cubic-dev-ai]

P1: The lockfile now uses revision 5, but the other jobs in this workflow still install uv 0.9.5 and run frozen syncs; those jobs will fail to read it. Upgrade the remaining lockfile-consuming jobs to a uv version that supports this revision.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. At .github/workflows/shared.yml, line 75:

<comment>The lockfile now uses revision 5, but the other jobs in this workflow still install uv 0.9.5 and run frozen syncs; those jobs will fail to read it. Upgrade the remaining lockfile-consuming jobs to a uv version that supports this revision.</comment>

<file context>
@@ -72,7 +72,7 @@ jobs:
         with:
           enable-cache: true
-          version: 0.9.5
+          version: 0.12.24
 
       - name: Install the project
</file context>

[claude]

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.