[Bug]: govern() config.audit_file is documented but never wired to AuditLog - audit is always in-memory only #3915

Package

agent-governance-toolkit-core

Description

GovernanceConfig.audit_file is documented as "Path for file-based audit log. None = in-memory only." but GovernedCallable.__init__ never reads it:

self._audit = AuditLog() if config.audit else None

AuditLog() is always constructed with no sink, regardless of audit_file. Confirmed by grepping the whole package - audit_file appears only in the field declaration and its own docstring in govern.py, nowhere else. Worse, the top-level govern() factory function (the module's own documented 2-line-integration entrypoint) doesn't even expose audit_file as a parameter, so a caller using govern(fn, policy=..., audit_file="...") gets a TypeError before ever reaching the dead config.

This isn't a missing feature - the library already has everything needed to make audit_file work: FileAuditSink (hash-chained, HMAC-signed JSON-lines, in audit_backends.py) and AuditLog(sink=...) both exist and are fully functional in isolation. govern() just never connects them.

Impact: every audit trail produced through govern() is lost on process exit, with no way to opt into persistence short of bypassing govern() entirely and constructing GovernedCallable/AuditLog/FileAuditSink by hand. For any compliance/audit use case (this is exactly what surfaced it - a policy-enforcement PoC that needs the audit trail to survive a restart), the documented audit_file knob looks like the supported way to do this and silently doesn't work.

Repro:

from agentmesh.governance import govern

def read_doc(doc_id): return {"doc_id": doc_id}

safe = govern(read_doc, policy="allow-all.yaml", audit_file="audit.jsonl")
# TypeError: govern() got an unexpected keyword argument 'audit_file'

How does this impact your work?

Found while evaluating AGT for a compliance/audit-trail use case (MAESTRO-7 - evidence sources, reasoning steps must be retained). The audit_file field is exactly what that needs, and it looked supported (documented dataclass field) but does nothing - not degraded, not slow, just silently discards persistence. Not currently blocked: workaround is bypassing govern() and wiring GovernedCallable/AuditLog/FileAuditSink by hand, but that defeats the point of the 2-line govern() integration this library advertises. Opening a PR with the fix (wires audit_file to FileAuditSink, adds audit_secret_key for HMAC signing, exposes both on the govern() factory) alongside this issue.

Timeline

No response

Steps to Reproduce

1. safe = govern(read_doc, policy="allow-all.yaml", audit_file="audit.jsonl") -> TypeError: govern() got an unexpected keyword argument 'audit_file' (not exposed on the factory at all).
2. 2. Working around that by constructing GovernanceConfig(policy=..., audit_file="audit.jsonl") directly and passing it to GovernedCallable: call the governed function a few times, then check for audit.jsonl on disk.
3. 3. No file is ever created - GovernedCallable.__init__ builds AuditLog() with no sink regardless of config.audit_file.

Environment

agent-governance-toolkit-core (agent-mesh package), Python 3.14, Windows 11. Verified against a fresh checkout of main.

Logs / Error Output

Code of Conduct

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