= Cutdown Capability Policy

== Principle

Capabilities are deny-by-default.

No extension may assume access to file system, network, process execution, or similar external resources unless explicitly declared and explicitly allowed by the host environment.

== Capability Manifest

Every extension must define a capability manifest entry:

- ``capabilities``: list of required capability IDs
- ``capability_reason``: short justification per capability

If no external access is needed, use ``capabilities: []``.

== Standard Capability IDs

- ``fs.read``
- ``fs.write``
- ``network.fetch``
- ``process.exec``

Additional IDs may be introduced only with Language owner approval.

== Enforcement Rules

- Extension behavior requiring a capability must be gated by explicit allowlist.
- If a required capability is not granted, behavior must degrade deterministically to documented fallback.
- Capability denial must emit a structured diagnostic code and recovery mode.

== Observability

Consumers should expose effective capability grants in parse/runtime metadata for reproducibility and auditability.

At minimum include:

- extension ID,
- requested capabilities,
- granted capabilities.

== Governance Integration

Any new extension proposal must include:

- capability manifest,
- denied-capability fallback behavior,
- conformance vectors for granted and denied capability states.

== Related

- [``./parser-profile-policy.md``](/latest/policies/parser-profile-policy)