feat: upgrade default Python runtime to PYTHON_3_14

[jesseturner21]

Description

Upgrade the default Python runtime version from PYTHON_3_13 to PYTHON_3_14 for new agents and MCP tools.

Changes:

• Add PYTHON_3_14 to the PythonRuntimeSchema Zod enum and all related type definitions
• Update all default constants (DEFAULT_PYTHON_VERSION) to PYTHON_3_14
• Add PYTHON_3_14 as "Latest" in the MCP Python version UI picker, demote 3.13
• Update packaging fallback, import constants mapping, and vended AGENTS.md template
• Update tests: schema validation, version extraction, schema-mapper expectations, and snapshots

Note: The JSON schema (schemas/agentcore.schema.v1.json) is auto-regenerated during the release workflow and is not modified in this PR. The Zod enum change will flow into the JSON schema at release time.

Related Issue

Merge order: The companion CDK constructs PR must be merged and released first, otherwise CDK synth will reject PYTHON_3_14 as an unknown runtime version.

• Companion CDK PR: https://github.com/aws/agentcore-l3-cdk-constructs/pull/146

Documentation PR

N/A

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

End-to-end verification:

• Created a new project with agentcore create --defaults — confirmed runtimeVersion: "PYTHON_3_14" in generated agentcore.json
• Deployed to AWS using a bundled distribution (CLI + CDK constructs) — CloudFormation template confirmed "Runtime": "PYTHON_3_14" on the AWS::BedrockAgentCore::Runtime resource
• Invoked the deployed runtime — received successful response (HTTP 200)

E2E CI note: The e2e (main) and e2e (npm) jobs will fail until the CDK constructs PR (https://github.com/aws/agentcore-l3-cdk-constructs/pull/146) is merged and released. The E2E tests install CDK constructs separately from npm or the CDK main branch, which don't yet include PYTHON_3_14 support.

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

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terms of your choice.

[github-actions]

Package Tarball

aws-agentcore-0.8.0.tgz

How to install

npm install https://github.com/aws/agentcore-cli/releases/download/pr-837-tarball/aws-agentcore-0.8.0.tgz

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	44.57%	7060 / 15840
🔵	Statements	44.04%	7491 / 17007
🔵	Functions	41.98%	1262 / 3006
🔵	Branches	43.59%	4752 / 10900

Generated in workflow #1790 for commit 3acc99d by the Vitest Coverage Report Action

[aidandaly24]

1. Missed defaults/fallbacks

Three files still hardcode PYTHON_3_13 as a default and need to be updated to PYTHON_3_14:

• src/lib/packaging/index.ts:81 — packCodeZipSync fallback: config.runtimeVersion ?? 'PYTHON_3_13'. The same pattern in python.ts:158 was updated but this one was missed.
• src/schema/llm-compacted/mcp.ts:180 — PythonRuntime type is missing 'PYTHON_3_14'. The CDK PR updated its copy of this file, and llm-compacted/agentcore.ts was updated in this PR, but this one was missed.
• src/cli/primitives/AgentPrimitive.tsx:529 — Hardcoded runtimeVersion: 'PYTHON_3_13' used when creating agents via the primitive.

2. Tests that should include PYTHON_3_14

• src/schema/schemas/__tests__/agent-env.test.ts:212 — The schema acceptance test iterates over ['PYTHON_3_10', ..., 'PYTHON_3_13'] to validate AgentEnvSpecSchema. PYTHON_3_14 should be added to this list.
• src/tui-harness/helpers.ts:106 — The TUI test harness fixture uses runtimeVersion: 'PYTHON_3_13' as its default. Should be updated so TUI integration tests run against the current default.

3. Docs still showing PYTHON_3_13

• docs/configuration.md:34,169 — Example configs show "runtimeVersion": "PYTHON_3_13".
• docs/configuration.md:203 — The "Runtime Versions" list doesn't include PYTHON_3_14.
• docs/container-builds.md:61 — Example config shows "runtimeVersion": "PYTHON_3_13".

[jesseturner21]

Thanks for the thorough review! All three categories addressed in 604f025:

1. Missed defaults/fallbacks — Fixed all three:

• src/lib/packaging/index.ts:81 — fallback updated to PYTHON_3_14
• src/schema/llm-compacted/mcp.ts:180 — added PYTHON_3_14 to PythonRuntime type
• src/cli/primitives/AgentPrimitive.tsx:529 — hardcoded runtimeVersion updated

2. Tests — Both updated:

• src/schema/schemas/__tests__/agent-env.test.ts:212 — PYTHON_3_14 added to the runtime version iteration list
• src/tui-harness/helpers.ts:106 — fixture default updated

3. Docs — All examples and the runtime versions list updated:

• docs/configuration.md — both example configs updated, PYTHON_3_14 added to the Runtime Versions list
• docs/container-builds.md — example config updated

All 3297 unit tests pass, pre-commit hooks (lint, prettier, typecheck) clean.