llm-ingestion-pipeline-security/src/llm_ingestion_guard/__init__.py

"""llm-ingestion-guard — a write-time defensive layer for LLM ingestion pipelines.

Query-time guardrails guard the answer; this library guards the *artifact*. It
packages the ingestion-side security contract — sanitize -> fence -> tool-less
quarantined transform -> per-stage capability isolation -> scan output before
persist -> fail-secure — as composable, stdlib-first, framework-agnostic code.

The library never makes the model call itself (no SDK is imported by the core),
so the public surface is a **toolkit plus two bookends** around the caller's
tool-less transform (BRIEF §6):

    prepared = prepare_input(untrusted_content)   # §6 steps 1-2: sanitize + fence
    output   = your_model(prepared.fenced)        # §6 step 3: tool-less, caller's job
    decision = screen_output(output, policy)      # §6 steps 6-7: scan + dispose

    if decision.disposition is Disposition.FAIL_SECURE:
        raise SystemExit  # halt + alert; never persist (§6 steps 7-8)

The individual detectors (:func:`sanitize`, :func:`scan_lexicon`,
:func:`scan_output`, ...), the contract asserters (:func:`assert_tool_less`,
:func:`scoped_env`, ...) and the disposition machinery are all exported for
pipelines that compose the checklist themselves. See ``docs/PLAN.md`` for the
build order and ``docs/BRIEF.md`` §6 for the contract this wiring encodes.
"""
from __future__ import annotations

from dataclasses import dataclass

from .report import Finding, Report, Severity, Source, severity_rank
from .sanitize import sanitize, SanitizeResult
from .entropy import scan_entropy, EntropyResult, DecodedBlob
from .lexicon import scan_lexicon, load_lexicon, LexiconPattern
from .fence import fence, FenceResult
from .neutralize import neutralize, NeutralizeResult
from .active_content import scan_active_content
from .output import scan_output, scan_secret_egress
from .disposition import (
    decide,
    guard,
    Policy,
    Trust,
    Provenance,
    Risk,
    Disposition,
    DispositionResult,
    DEFAULT_ACTION_MAP,
    PRESET_TRUSTED_SOURCE,
    PRESET_USER_UPLOAD,
)
from .contract import (
    assert_tool_less,
    assert_credential_allowlist,
    assert_within_input_cap,
    credential_env_names,
    scoped_env,
    ContractViolation,
    OversizeInputError,
)
from .grounding import (
    SourceGroundingCheck,
    no_grounding_check,
    DEFAULT_GROUNDING_CHECK,
)
from . import okf

__version__ = "1.4.1"


# --- §6 bookends: the two library-side halves around the transform ---------


@dataclass(frozen=True)
class PreparedInput:
    """Untrusted content made ready for a tool-less transform (§6 steps 1-2).

    ``fenced`` is the sanitized, spotlight-fenced text to hand the model.
    ``nonce`` is the per-call fence delimiter — a caller may check for it in the
    output to detect a fence breakout. ``report`` merges the sanitize and fence
    findings so the caller can gate on the *input* too, not only the output.
    """

    fenced: str
    nonce: str
    report: Report


def prepare_input(text: str, source: Source = Source.INPUT) -> PreparedInput:
    """Sanitize then fence untrusted ``text`` (BRIEF §6 steps 1-2).

    Strips carrier classes first (:func:`sanitize`), then spotlight-fences the
    cleaned payload in a randomized per-call delimiter (:func:`fence`) — sanitize
    *before* fence so a carrier can never smuggle a forged delimiter. The merged
    report carries both steps' findings; ``prepare_input`` itself renders no
    disposition (design principle 4 — the caller decides).
    """
    sanitized = sanitize(text, source)
    fenced = fence(sanitized.text, source)
    report = Report()
    report.extend(sanitized.report.findings)
    report.extend(fenced.report.findings)
    return PreparedInput(fenced=fenced.text, nonce=fenced.nonce, report=report)


def screen_output(
    text: str,
    policy: Policy,
    *,
    provenance: Provenance = Provenance.PROSE,
    transform_failed: bool = False,
) -> DispositionResult:
    """Scan the emitted ``text`` and dispose it, failing *closed* (§6 steps 6-7).

    Runs :func:`scan_output` (lexicon + entropy + decode-and-rescan + secret
    egress) under :func:`guard`, so a scanner that errors on crafted input yields
    ``FAIL_SECURE`` rather than an auto-persist — an un-scannable artifact is
    never committed. ``transform_failed=True`` (the caller's model call raised or
    fell back) plus any finding is treated as a probable forced-fallback attack
    and also halts, regardless of trust tier.
    """
    return guard(
        lambda: scan_output(text, source=Source.OUTPUT),
        policy,
        provenance=provenance,
        transform_failed=transform_failed,
    )


__all__ = [
    "__version__",
    # shared types
    "Finding", "Report", "Severity", "Source", "severity_rank",
    # input-side detectors + result types
    "sanitize", "SanitizeResult",
    "scan_entropy", "EntropyResult", "DecodedBlob",
    "scan_lexicon", "load_lexicon", "LexiconPattern",
    "fence", "FenceResult",
    "neutralize", "NeutralizeResult",
    # output-side
    "scan_output", "scan_secret_egress", "scan_active_content",
    # disposition — `Risk` is the assessment axis, `Disposition` the action
    "decide", "guard", "Policy", "Trust", "Provenance",
    "Risk", "Disposition", "DispositionResult", "DEFAULT_ACTION_MAP",
    "PRESET_TRUSTED_SOURCE", "PRESET_USER_UPLOAD",
    # contract asserters
    "assert_tool_less", "assert_credential_allowlist",
    "credential_env_names", "scoped_env", "ContractViolation",
    "assert_within_input_cap", "OversizeInputError",
    # grounding seam
    "SourceGroundingCheck", "no_grounding_check", "DEFAULT_GROUNDING_CHECK",
    # §6 bookends
    "prepare_input", "screen_output", "PreparedInput",
    # OKF adapter (v0.2) — the format-specific layer, as its own namespace
    "okf",
]