feat(seatbelt): add system power access by caarlos0 · Pull Request #1066 · microsoft/mxc

Carlos Alexandro Becker (caarlos0) · 2026-08-28T20:08:04Z

📖 Description

Add opt-in seatbelt.systemPowerAccess support for macOS workloads that need
sleep/wake notifications or power assertions.

The capability is off by default. When enabled, the generated Seatbelt profile
allows only:

RootDomainUserClient
com.apple.PowerManagement.control
com.apple.iokit.powerdxpc

The new field is available in schema 0.9.0-alpha and later. This change wires
it through the versioned contract, parser, Rust and Node SDKs, generated
artifacts, tests, and documentation. Published 0.7 and 0.8 schemas remain
unchanged.

🔗 References

None.

🔍 Validation

Verified both macOS power APIs are denied with systemPowerAccess: false and
allowed with systemPowerAccess: true through mxc-exec-mac.
Ran targeted Seatbelt, config contract, parser, and Rust SDK tests.
Built the Node SDK and ran its wire-conformance test.
Ran schema/type codegen, schema-version, and config-validation gates.
Ran Rust formatting and Clippy checks.
Merged the latest main and reran the full PR validation.

✅ Checklist

Signed the Contributor License Agreement
Linked to an issue
Updated documentation (if applicable)
Updated Copilot instructions (if build, architecture, or conventions changed)
If this PR changes Cargo.lock, the dependency-feed-check check passes (see docs/pull-requests.md)

📋 Issue Type

Bug fix
Feature
Task

GitHub Actions runs the PR validation build automatically. The ADO pipeline
(MXC-PR-Build) is the Azure version of the PR pipeline, kept in parity with the GitHub
Actions build; it runs on merge to main, and Microsoft reviewers with write access can trigger it
on a PR with /azp run. See docs/pull-requests.md.

If the dependency-feed-check check fails on a new dependency, the crate must be added to
the feed before the PR can pass. See docs/pull-requests.md
for the steps.

Microsoft Reviewers: Open in CodeFlow

Add an opt-in capability for sleep/wake notifications and power assertions while keeping the default sandbox profile restricted. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 342a9bf7-a27a-457f-aaac-c910b8cd5535 Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

azure-pipelines · 2026-08-28T20:08:13Z

Azure Pipelines: There may be pipelines that require an authorized user to comment /azp run to run.

Copilot

Copilot review overview

Review tier: Balanced
Findings: 2 · 1

New issues introduced by this change (3)

Severity	Finding
	`src/core/wxc_common/src/config_parser.rs` — `systemPowerAccess` is mapped without any schema-version check. The production loaders still…
	`src/core/mxc_engine/src/policy.rs` — This public setter bypasses schema validation because `build_request` has already parsed the…
	`docs/schema.md` — This example places `systemPowerAccess` under `experimental.seatbelt`, but the parser explicitly…

What changed in this PR

Adds opt-in macOS Seatbelt permissions for sleep/wake notifications and power assertions.

Changes:

Extends schema, parser, Rust SDK, and Node SDK contracts.
Emits narrowly scoped Seatbelt power-service rules.
Adds unit tests, generated artifacts, and documentation.

File	Description
`src/core/wxc_common/src/wire.rs`	Adds the wire field.
`src/core/wxc_common/src/models.rs`	Adds the domain setting and default.
`src/core/wxc_common/src/config_parser.rs`	Maps and tests the setting.
`src/core/wxc_common/src/config_contract_adapters/v0_8.rs`	Defaults the unavailable field.
`src/core/wxc_common/src/config_contract_adapters/v0_7.rs`	Defaults the unavailable field.
`src/core/wxc_common/src/config_contract_adapters/dev/one_shot.rs`	Adapts the 0.9 contract field.
`src/core/wxc_common/src/config_contract_adapters/dev/one_shot_tests/stable_candidate.rs`	Tests adapter mappings.
`src/core/mxc-sdk/README.md`	Documents Rust SDK usage.
`src/core/mxc_engine/src/policy.rs`	Adds the Rust SDK setter.
`src/core/mxc_config_contract/tests/version_boundaries/seatbelt.rs`	Tests 0.9 introduction.
`src/core/mxc_config_contract/tests/v0_9_0_alpha/seatbelt.rs`	Tests field typing.
`src/core/mxc_config_contract/tests/v0_9_0_alpha/optional_fields.rs`	Tests null rejection.
`src/core/mxc_config_contract/tests/v0_9_0_alpha/fixtures/one_shot/valid/seatbelt_complete.json`	Extends the valid fixture.
`src/core/mxc_config_contract/src/dev/stable.rs`	Adds the exact contract field.
`src/backends/seatbelt/common/src/profile_builder.rs`	Generates and tests power rules.
`sdk/node/src/types.ts`	Exposes the Node SDK option.
`sdk/node/src/generated/wire.ts`	Updates rolling generated types.
`sdk/node/src/generated/v0_9_0_alpha/wire.ts`	Updates exact generated types.
`sdk/node/README.md`	Documents Node SDK usage.
`schemas/dev/mxc-config.schema.0.9.0-dev.json`	Updates the rolling schema.
`schemas/dev/mxc-config.schema.0.9.0-alpha.json`	Updates the exact schema.
`docs/seatbelt/seatbelt-backend.md`	Documents backend behavior.
`docs/schema.md`	Updates the configuration example.

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Copilot

Copilot review overview

Review tier: Balanced
Findings: 2 · 1

Pre-existing issues (3)

Severity	Finding
	`src/core/mxc_engine/src/policy.rs` — This public setter bypasses schema validation because `build_request` has already parsed the… View comment
	`src/core/wxc_common/src/config_parser.rs` — `systemPowerAccess` is mapped without any schema-version check. The production loaders still… View comment
	`docs/schema.md` — This example places `systemPowerAccess` under `experimental.seatbelt`, but the parser explicitly… View comment

Suppressed comments (3)

src/core/mxc_engine/src/policy.rs:688

This mutator bypasses the advertised 0.9 schema boundary: callers can build and validate a 0.7/0.8 request, then set this model field after parsing, and the Seatbelt runner applies it without checking schema_version. The new test even exercises that path with 0.7.0-alpha. Make the setter reject unsupported versions (or add an execution-time invariant covering directly constructed requests) so the Rust SDK cannot enable a 0.9-only capability under an older contract.

    pub fn set_seatbelt_system_power_access(&mut self, allow: bool) -> &mut Self {
        self.inner
            .seatbelt
            .get_or_insert_default()
            .system_power_access = allow;

docs/schema.md:209

This example places the new option under experimental.seatbelt, but the parser explicitly rejects that section with “has moved to the stable section”; the supported path is top-level seatbelt.systemPowerAccess. Move the Seatbelt example out of the experimental object so readers can copy a valid 0.9 configuration.

            "systemPowerAccess": false      // Allow sleep/wake notifications and power assertions

src/core/wxc_common/src/config_parser.rs:623

systemPowerAccess is not version-gated in the production parser. Both production loaders still deserialize the rolling wire::MxcConfig directly, and the exact-contract adapters are explicitly not reachable from production, so a request declaring schema 0.7 or 0.8 can set this field to true and reach the profile builder. The contract boundary test alone does not enforce the runtime boundary. Add a raw field-version check to both loader paths (similar to directional networking) and a production parser regression test that rejects this field before 0.9.

        system_power_access: system_power_access.unwrap_or(false),

Gate systemPowerAccess at every one-shot loader and again before Seatbelt execution so post-parse SDK mutations cannot bypass schema 0.9. Move the documented Seatbelt block to its supported top-level location. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 342a9bf7-a27a-457f-aaac-c910b8cd5535 Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

Copilot

Copilot review overview

Review tier: Balanced
Findings: 1

New issues introduced by this change (1)

Severity	Finding
	`docs/schema.md` — This “Full Schema” example still declares `"version": "0.6.0-alpha"` at line 87, but the parser…

Issues resolved since last review (3)

Severity	Finding
	`docs/schema.md` — This example places `systemPowerAccess` under `experimental.seatbelt`, but the parser explicitly… View resolved comment
	`src/core/mxc_engine/src/policy.rs` — This public setter bypasses schema validation because `build_request` has already parsed the… View resolved comment
	`src/core/wxc_common/src/config_parser.rs` — `systemPowerAccess` is mapped without any schema-version check. The production loaders still… View resolved comment

Copilot

Copilot review overview

Review tier: Balanced
Findings: 1

Pre-existing issues (1)

Severity	Finding
	`docs/schema.md` — This “Full Schema” example still declares `"version": "0.6.0-alpha"` at line 87, but the parser… View comment

Keep the full schema example consistent with its systemPowerAccess field. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 342a9bf7-a27a-457f-aaac-c910b8cd5535 Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

Copilot

Copilot review overview

Review tier: Balanced
Findings: None

Issues resolved since last review (1)

Severity	Finding
	`docs/schema.md` — This “Full Schema” example still declares `"version": "0.6.0-alpha"` at line 87, but the parser… View resolved comment

Resolve the Seatbelt policy move by keeping execution invariants in the backend and raw schema-version gates in wxc_common. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 342a9bf7-a27a-457f-aaac-c910b8cd5535 Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>

Copilot

Copilot review overview

Review tier: Balanced
Findings: None

Copilot

Copilot review overview

Review tier: Balanced
Findings: None

Darren Hoehna (dhoehna) · 2026-09-01T18:49:18Z

    Ok(())
 }

+/// Emit the narrow Seatbelt capability needed for system power notifications


What is a narrow capability?

Darren Hoehna (dhoehna) · 2026-09-01T18:51:28Z

+/// Emit the narrow Seatbelt capability needed for system power notifications
+/// and assertions. Off by default because opening `RootDomainUserClient` also
+/// exposes host power-management operations beyond notification registration.
+fn write_system_power_rules(out: &mut String, request: &ExecutionRequest) {


Most methods have the out parameter as the last parameter. Can the out variable be moved to the end? Also, why have an out param instead of a return value?

Darren Hoehna (dhoehna) · 2026-09-01T18:52:35Z

+    fn system_power_access_default_off_omits_power_services() {
+        let r = req();
+        let p = build_profile(&r).unwrap();
+        assert!(!p.contains("systemPowerAccess"));


Can these strings ever change? If they do will this test catch that change?

Darren Hoehna (dhoehna) · 2026-09-01T18:56:00Z

+        });
+        let p = build_profile(&r).unwrap();
+        assert!(p.contains("systemPowerAccess"));
+        assert!(p.contains("(global-name \"com.apple.PowerManagement.control\")"));


Kinda odd that the names here have a quite around them but the previous test has no quotes. Is this delibrate?

Darren Hoehna (dhoehna) · 2026-09-01T18:58:20Z


+    #[test]
+    fn system_power_access_support_starts_at_v09() {
+        assert_eq!(system_power_access_support("0.8.0-alpha"), Some(false));


Why only go down to 0.8.0?

Darren Hoehna (dhoehna) · 2026-09-01T18:59:01Z

    }

+    #[test]
+    fn rejects_system_power_access_before_v09() {


Looks like this is the same test as system_power_access_validation_rejects_pre_v09_requests?

Darren Hoehna (dhoehna) · 2026-09-01T19:01:59Z

    pub keychain_access: OptionalField<bool>,
+    /// Whether system sleep/wake notifications and power assertions are allowed.
+    #[serde(default)]
+    pub system_power_access: OptionalField<bool>,


The comment states power assertions but the variable is power_access

Darren Hoehna (dhoehna) · 2026-09-01T19:02:31Z


+#[test]
+fn rejects_non_boolean_system_power_access_values() {
+    for system_power_access in ["0", "1", "\"string\"", "[]", "{}"] {


I think Copilot went a bit too in-depth with its unit testing.

Darren Hoehna (dhoehna) · 2026-09-01T19:06:03Z

    Ok(())
 }

+fn validate_one_shot_field_versions(config: &serde_json::Value) -> Result<(), WxcError> {


These tests belong in seatbelt not wxc. power access is a seatbelt specific functionality.

Branden Bonaby (bbonaby)

We should be careful with the features we're adding before 1.0 is locked down. We don't want to overly add features to the backends that we haven't discussed a need for. Let's chat to see where this requirement is coming from.

CC: Anis Mohammed Khaja Mohideen (@kanismohammed)

Carlos Alexandro Becker (caarlos0) · 2026-09-03T18:07:52Z

talked with Anis, will hold this for now. Will move this to draft.

Carlos Alexandro Becker (caarlos0) requested review from a team and a balanced review from Copilot August 28, 2026 20:08

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Copilot started reviewing on behalf of Carlos Alexandro Becker (caarlos0) August 28, 2026 20:08 View session

Merge remote-tracking branch 'origin/main' into macos-bazel

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microsoft-github-policy-service Bot added the Copilot-Instructions PR modifies Copilot instruction files (.github/copilot-instructions.md or .github/instructions/) label Aug 31, 2026

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Merge remote-tracking branch 'origin/main' into macos-bazel

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microsoft-github-policy-service Bot assigned Carlos Alexandro Becker (caarlos0) Sep 3, 2026

microsoft-github-policy-service Bot added the Needs-Author-Feedback Issue needs attention from issue or PR author label Sep 3, 2026

Carlos Alexandro Becker (caarlos0) marked this pull request as draft September 3, 2026 18:07

microsoft-github-policy-service Bot added Needs-Attention Issue needs attention from Microsoft and removed Needs-Author-Feedback Issue needs attention from issue or PR author labels Sep 3, 2026

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📖 Description

🔗 References

🔍 Validation

✅ Checklist

📋 Issue Type

Microsoft Reviewers: Open in CodeFlow

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Carlos Alexandro Becker (caarlos0) commented Aug 28, 2026 •

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