Policy Context

Native policies share one context across CEL, Starlark, OPA, and JSON Schema. Atmos collects runtime facts outside the evaluators and supplies the same snapshot to each rule within an evaluation. This capability requires the release containing these changes; it is not available in 1.233.0.

Available facts

Context	Contents
env	Process environment variables, including CLAUDECODE and CODEX_THREAD_ID
atmos	version and active fips mode
runtime	os, arch, effective user.uid, user.gid, user.username
runtime.memory	available_bytes, total_bytes, and scope (host or container)
runtime.disk	path, available_bytes, and total_bytes for the current working directory's filesystem
time	UTC now timestamp, date, weekday, and timezone
ci	Native metadata/event/facts plus labels and verified approvers
checks	Named results from shared version, date, and schedule checks

An unavailable measurement is null, not zero. Numeric UID/GID are unavailable on Windows. Memory uses readable conventional Linux cgroup limits when detected; check scope when container-specific capacity is required. Disk space describes the stated path, which may differ from a component or temporary directory. Capacity is a snapshot, not a reservation.

The CLI pins environment variables before configuration evaluation. Treat environment-based agent detection as an accidental-operation guardrail: callers can alter their environment. Clock and resource facts are sampled again at subsequent gates, so an apply after a long plan uses the current deployment window and capacity measurements. Context can contain secrets; never include environment values in policy diagnostics.

Language bindings

Engine	Access
CEL	env.CLAUDECODE, atmos.fips, runtime.user.uid, checks.window
Starlark	ctx.env.get("CLAUDECODE", ""), ctx.atmos["fips"], ctx.checks["window"]
OPA	data.atmos_context.env.CLAUDECODE, data.atmos_context.checks.window
JSON Schema	Set schema.target: context, then validate properties.env, properties.checks, etc.

OPA retains the original document as input. JSON Schema defaults to schema.target: input, so existing schemas continue to validate the original document. The context target includes input, params, request, and the shared fields above.

An unset environment variable is absent; an explicitly empty value remains "". For optional variables, CEL uses has(env.CLAUDECODE) && env.CLAUDECODE == '1', Starlark can use ctx.env.get("CLAUDECODE", ""), and OPA can use object.get(data.atmos_context.env, "CLAUDECODE", ""). JSON Schema makes presence mandatory only with required. A shared check pointing to a missing variable fails with unavailable input rather than silently returning false.

Version and deployment-window checks

Named checks use the same implementation for every engine. Their values are booleans; the engine predicate decides whether they select an action.

apiVersion: atmos/v1
kind: Policy
metadata:
  name: production-runtime
spec:
  policies:
    deploy:
      on: component.command
      match:
        labels: {stage: prod}
      checks:
        supported_version:
          kind: semver
          path: /atmos/version
          constraint: '>= 1.233.0'
        window:
          kind: schedule
          timezone: America/New_York
          weekdays: [Monday, Tuesday, Wednesday, Thursday]
          start_time: '09:00'
          end_time: '17:00'
      rule: >-
        input.command in ['apply', 'deploy'] &&
        (!checks.supported_version || !checks.window || !atmos.fips)
      action: deny
      reason: Production deployments require an approved runtime and deployment window.

Semantic versions use numeric ordering and prerelease-aware constraints. Unknown development versions fail a version check. A schedule defaults to the captured /time/now and UTC; an IANA timezone applies its daylight-saving rules. Start boundaries are inclusive; end boundaries are exclusive. Split overnight windows into two checks and combine them with OR.

Validate dates and ranges

checks:
  expiration:
    kind: date
    path: /input/expiration
    format: date
    start: '2026-01-01'
    end: '2027-01-01'

Formats are date (YYYY-MM-DD), date-time (RFC3339, the default), and time (HH:MM:SS). Checks validate calendar values as well as syntax. Missing or null source fields are errors; present invalid dates return false. Omit bounds to check format/calendar validity alone. JSON Schema also asserts standard formats such as date and date-time.

For JSON Schema, consume the same named check using a context schema:

engine: jsonschema
schema:
  path: schemas/runtime.schema.json
  target: context

{
  "type": "object",
  "required": ["checks"],
  "properties": {
    "checks": {
      "type": "object",
      "required": ["expiration"],
      "properties": {"expiration": {"const": true}}
    }
  }
}

A schema violation selects the configured action, just like document validation.

CI labels and approvers

Local execution has ci: null. In GitHub Actions, ci.labels contains label names from a complete PR event; null means unavailable and [] means known empty. Labels describe the triggering event and are not a fresh API lookup. Native datasets retain their provenance.

rule: ci != null && ci.labels != null && 'preview' in ci.labels

To inspect verified approvers, explicitly request collection:

required_ci:
  - provider: github-actions
    schema: github-actions/v1
    dataset: facts
    fact: approvers
rule: "!('alice' in ci.approvers)"
action: deny
reason: A current approval from alice is required.

Operational policy gates collect reviews when requested. Offline file checks never fetch review evidence; use fixture evidence with policy test when testing approver rules.

Collection requires pull-requests: read and verifies the open PR, checked-out revision, complete paginated reviews, and unchanged revisions during collection. Names are lowercase; author, stale, dismissed, and superseded approvals do not count. Missing required evidence fails closed. Other CI providers leave unsupported summaries unavailable. For approval obligations, prefer require-approval policies.

Offline tests

A test fixture can provide request.context with env, atmos, runtime, and time values, and request.ci with native datasets. atmos policy test never collects live host or CI facts. A fixture that omits context receives empty/unavailable facts. This keeps calendar and machine-dependent policies reproducible. Unavailable host string fields, such as time.now and atmos.version, are absent. A shared check requiring one reports input_unavailable. Explicitly empty environment or input strings remain present and produce a false date/version check result.