feat: standardize timeout values to floats in seconds

[yugannkt]

Standardize timeout values to floats in seconds

Summary

Standardizes all timeout parameters across the SDK to use float values representing seconds, following Python ecosystem conventions (httpx, starlette, stdlib).

Motivation and Context

• Timeout values were inconsistent, mixing timedelta and float types
• Python ecosystem standards use floats representing seconds for timeouts
• Eliminates unnecessary complexity and improves API consistency
• Aligns with community expectations and reduces cognitive load

Changes Made

• Converted all timeout parameters from timedelta | None to float | None
• Updated StreamableHttpParameters and SseServerParameters to use float values
• Removed timedelta imports and conversion logic
• Updated all examples and tests to use float values
• Added "(in seconds)" clarification to all timeout parameter docstrings

Files Modified: 9 files across core SDK, examples, and tests

How Has This Been Tested?

• All modified Python files compile successfully
• Type consistency verified across all timeout parameters
• Default values aligned across all transport types
• Documentation consistency verified
• Examples validated with new float-based API

Breaking Changes

YES - This is a breaking change for v2

Migration:

# Before
from datetime import timedelta
params = StreamableHttpParameters(timeout=timedelta(seconds=30))

# After
params = StreamableHttpParameters(timeout=30.0)

Replace timedelta(seconds=X) with X.0 and remove unused timedelta imports.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added or updated documentation as needed

Additional context

Default Timeout Values:

• SSE timeout: 5.0 seconds
• SSE read timeout: 300.0 seconds (5 minutes)
• StreamableHTTP timeout: 30.0 seconds
• StreamableHTTP read timeout: 300.0 seconds (5 minutes)

Design: Aligns with Python ecosystem standards, maintains equivalent behavior, uses explicit .0 notation for clarity.

Fixes #1747

[felixweinberger]

Thanks - as you mentioned this is a breaking change but we're starting work on that now, so marking this as draft for now and have added it to our internal tracking, we'll come back to this.