The Release Decision¶

pharos.disclosure evaluates whether derived outputs may leave an enclave, why, and when an analyst or authority must review the decision.

Decision Evaluation Flowchart¶

flowchart TD
    Start["Input Label + Operating Purpose"] --> CheckLevel{"Sensitivity <= Ceiling?"}
    CheckLevel -- No --> WithholdLevel["🔴 WITHHOLD (LEVEL_ABOVE_CEILING)"]
    CheckLevel -- Yes --> CheckCapacity{"Capacity Declassifiable?"}
    CheckCapacity -- No --> WithholdCap["🔴 WITHHOLD (CAPACITY_NOT_DECLASSIFIABLE)"]
    CheckCapacity -- Yes --> CheckPurpose{"Purpose Prohibited?"}
    CheckPurpose -- Yes --> WithholdPurpose["🔴 WITHHOLD (PURPOSE_PROHIBITED)"]
    CheckPurpose -- No --> CheckComp{"Compartments Held?"}
    CheckComp -- No --> Approval["🟡 APPROVAL (COMPARTMENT_NOT_HELD)"]
    CheckComp -- Yes --> Release["🟢 RELEASE (RELEASABLE)"]

Three Governance Dispositions¶

Unlike binary boolean gates, Pharos enforces three explicit governance dispositions:

Disposition	Meaning	Operational Action
`RELEASE`	Approved for immediate release	Leaves without human intervention
`APPROVAL`	Blocked, but authorizable	Escalates to human authority for compartment clearance
`WITHHOLD`	Strictly blocked	Cannot be released under any authority

Why Approval Matters

A compartment shortfall is an authorizable policy decision. Distinguishing APPROVAL from WITHHOLD prevents permanent blockades on outputs where human authorities have clearance to override compartment restrictions.

Governed Reason Codes¶

Every release decision emits an explicit reason code to support auditing and provenance tracking:

Reason Code	Disposition	Root Cause & Resolution
`RELEASABLE`	`RELEASE`	Passes all lattice dominance and policy checks
`COMPARTMENT_NOT_HELD`	`APPROVAL`	Requires clearance from an authority holding the target compartment
`LEVEL_ABOVE_CEILING`	`WITHHOLD`	Sensitivity level exceeds aggregator ceiling
`CAPACITY_NOT_DECLASSIFIABLE`	`WITHHOLD`	Output format (e.g. `FREETEXT`) is ineligible for release
`PURPOSE_PROHIBITED`	`WITHHOLD`	Use case is prohibited by data owner restrictions

Most-Binding Ordering

Reason evaluation is ordered by severity. A label failing multiple checks reports the most restrictive, non-liftable reason (e.g. LEVEL_ABOVE_CEILING over COMPARTMENT_NOT_HELD).

Purpose Limitation Axis¶

Clearance and sensitivity evaluate who may read data. Purpose limitation evaluates what the reading is used for:

from pharos.disclosure import ProhibitedUse, Purpose, ReleasePolicy, decide

policy = ReleasePolicy(
    declassification=DROP_COMPARTMENTS,
    prohibited=frozenset({ProhibitedUse(Compartment.LEGAL, Purpose.FLEET_TRAINING)}),
)

# Evaluating same label under different operational purposes:
decide(label, ceiling, policy, purpose=Purpose.FLEET_TRAINING).disposition  # WITHHOLD
decide(label, ceiling, policy, purpose=Purpose.INCIDENT_REVIEW).disposition  # RELEASE

Governance Function Distinction¶

Function	Input	Purpose
`decide(...)`	Source Data Label	Applies full declassification policies to original evidence
`admit(...)`	Derived/Released Output	Verifies an already-declassified proposal (prevents double declassification)

Audited Case Verification¶

Pharos maintains a verified suite of disclosure test cases in src/pharos/cases/disclosure.json.

# Run verified disclosure test cases
uv run python -m pytest tests/test_disclosure.py -q