feat(sdk): Python SDK — Extract from JarvisCore, Publish to PyPI

[sangalo20]

Overview

The current Go SDK (nexus-sdk) is solid infrastructure but the majority of AI agent developers work in Python. A standalone, pip-installable Python SDK is critical for adoption.

Problem

• A Python SDK exists inside jarviscore as jarviscore.nexus.NexusClient but is not standalone
• Every Python agent developer must write their own HTTP client against the Gateway REST API
• No PyPI package exists, so usage is limited to teams with direct access to JarvisCore

Proposed Solution

Extract, extend, and publish the Python SDK to PyPI as nexus-sdk.

Target interface

from nexus import NexusClient

nexus = NexusClient(gateway_url="https://nexus-gateway.acme.com")

# Standard agent session
session = nexus.request_agent_session(
    agent_id="crm-agent",
    provider="salesforce",
    scopes=["crm:contacts:read"],
    ttl=900
)
# session.access_token  → ready to use
# session.expires_at    → datetime
# session.scopes_granted → list

# OBO session
obo = nexus.request_obo_session(
    agent_id="ops-agent",
    provider="internal-ops",
    scopes=["acme:gliding"],
    user_context_token=request.headers["X-User-Token"]
)
# obo.acting_for, obo.tenant_id, obo.clearance_level

# Close when done
nexus.close_agent_session(session.session_id)

Installation

pip install nexus-sdk

Tasks

• Create nexus-sdk-python/ directory in the monorepo (or separate repo)
• Extract core HTTP client from JarvisCore
• Add request_agent_session(), request_obo_session(), close_agent_session(), get_agent_session() methods
• Add retry + backoff logic matching Go SDK behavior
• Add WaitForActive() polling helper
• Publish to PyPI as nexus-sdk
• Add README and usage examples

Priority

P3 — Small effort (core extraction; session methods depend on P1/P2)

Reference

AGENT_AUTH_PROPOSAL.md — Proposal 5 (Python)