feat: support Ultra Fast Create for Aurora Postgres cluster (i.e. expression cluster)

[kennthhz]

Fixes

Summary

Support Ultra Fast Create for Aurora Postgres cluster (i.e. expression cluster)

Changes

1. Add new API support to create express cluster (UFC)
2. Add E2E test case
3. Improve psycopg connection pool

User experience

Support Ultra Fast Create for Aurora Postgres cluster

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• [ x] I have reviewed the contributing guidelines
• [ x] I have performed a self-review of this change
• [ x] Changes have been tested
• [ x] Changes are documented

Is this a breaking change? (Y/N)

N

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.

[codecov]

Codecov Report

❌ Patch coverage is 92.16867% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.35%. Comparing base (8ef8460) to head (09c75de).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ostgres_mcp_server/connection/cp_api_connection.py	91.52%	5 Missing and 5 partials ⚠️
...s_mcp_server/connection/psycopg_pool_connection.py	88.88%	2 Missing ⚠️
...s-mcp-server/awslabs/postgres_mcp_server/server.py	96.15%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #2801    +/-   ##
========================================
  Coverage   91.35%   91.35%            
========================================
  Files        1011     1011            
  Lines       74361    74478   +117     
  Branches    11959    11979    +20     
========================================
+ Hits        67934    68041   +107     
- Misses       3973     3978     +5     
- Partials     2454     2459     +5     

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[Copilot]

Pull request overview

Adds Ultra Fast Create (Aurora PostgreSQL “Express” clusters) support to the postgres MCP server, along with connection/pool robustness improvements and expanded test coverage around the new flows.

Changes:

• Add express-cluster creation path (with_express_configuration=True) and related AWS control-plane helpers (create + delete).
• Make connect_to_database async and eagerly initialize psycopg pools (with cleanup on pool init failure).
• Add/extend unit tests and introduce an end-to-end integration test script for real cluster creation.

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
src/postgres-mcp-server/uv.lock	Updates locked AWS SDK dependency versions.
src/postgres-mcp-server/pyproject.toml	Bumps boto3/botocore minimum versions.
src/postgres-mcp-server/awslabs/postgres_mcp_server/server.py	Implements express cluster creation option; renames internal connection helper; makes connect tool async; adjusts error handling and pool init behavior.
src/postgres-mcp-server/awslabs/postgres_mcp_server/connection/cp_api_connection.py	Adds express cluster create helper and cluster deletion helper; improves exception logging.
src/postgres-mcp-server/awslabs/postgres_mcp_server/connection/psycopg_pool_connection.py	Hardens pool initialization and adds richer logging + expiry diagnostics.
src/postgres-mcp-server/awslabs/postgres_mcp_server/connection/rds_api_connection.py	Improves transaction rollback logging and exception propagation style.
src/postgres-mcp-server/tests/test_server.py	Updates tests for new behaviors and adds express create_cluster coverage.
src/postgres-mcp-server/tests/test_server_internal_functions.py	Updates tests to new internal connection function name.
src/postgres-mcp-server/tests/test_server_error_handling.py	Updates for async connect tool + adds pool init success/failure tests.
src/postgres-mcp-server/tests/test_psycopg_connector.py	Adds test ensuring pool is cleared on open failure.
src/postgres-mcp-server/tests/test_cp_api_simple_functions.py	Updates expected error message for instance lookup failure.
src/postgres-mcp-server/tests/test_cp_api_connection.py	Adds tests for express cluster creation and cluster deletion.
src/postgres-mcp-server/tests/e2e_integration_test.py	Adds a live AWS E2E integration script for express + serverless clusters and cleanup.
src/postgres-mcp-server/kiro_power/steering/aurora-postgres-mcp.md	Documents when/how to use express vs regular clusters.
src/postgres-mcp-server/kiro_power/POWER.md	Updates operational guidance for express vs regular clusters and connection methods.

Comments suppressed due to low confidence (1)

src/postgres-mcp-server/awslabs/postgres_mcp_server/server.py:573

• Port is hard-coded to 5432 when creating the cached connection after serverless cluster creation. If the cluster port ever differs (or becomes configurable), this will cache a connection under the wrong port; use cluster_result['Port'] (or fetch from cluster properties) instead of a constant.

        internal_create_connection(
            region=region,
            database_type=database_type,
            connection_method=connection_method,
            cluster_identifier=cluster_identifier,
            db_endpoint=cluster_result['Endpoint'],
            port=5432,
            database=database,
        )

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[MichaelWalker-git]

LGTM