[BUG] MUT-021: Second project load can reuse the first project's agent module #69

Problem

Loading project B after project A in one process: from agent import VALUE in B’s adapter still resolved to A’s agent.py (sys.modules cache). Confirmed in audit: B factory returned "A". Sample AGENT_REF = "agent:support_agent" makes this the default module name.

Why it matters

Low for one-shot CLI. High for tests, notebooks, or any in-process multi-project runner. Wrong agent silently under test.

Evidence

• Audit ID: MUT-021 (MEDIUM, confirmed).
• packages/mutiny_openai_agents/src/mutiny_openai_agents/loader.py ensure_project_on_path + importlib.import_module.
• Audit: two temp projects loaded sequentially; second factory returned the first project’s value.

Reproduction

Audit in-process sequential load. Not independently re-run in this filing pass; loader still uses bare import_module(module_name) on current main.

Expected behavior

Each project root loads its own agent module (or uniquely named modules). Loading B after A returns B’s factory.

Suggested implementation direction

Unique module names per project root, or isolate/pop sys.modules entries you loaded. Avoid breaking AGENT_REF = "agent:support_agent" for one-shot CLI.

Acceptance criteria

• Sequential load of two temp projects with agent.py returning different markers yields the second project’s marker.
• Sample mutiny run / mutiny test still work.
• Unit test in adapter loader tests.
• No change to Hosted observe-only (does not load customer adapters).

Scope

mutiny_openai_agents/loader.py (+ tests). Out of scope: demo_agent process globals (MUT-046, skipped — Hosted concurrency=1).

Related audit findings

MUT-021. Related skipped: MUT-046.

Contributor notes

Generated from the Mutiny deep audit.

help wanted.