claw/docs/superpowers/reports/2026-04-18-g6-host-bridge-runtime-contract-report.md

G6 Host Bridge Runtime Contract Report

Date: 2026-04-18 Scope: G6 minimum runtime contract implementation

Summary

G6 has moved from pure fail-closed classification to a minimum runnable runtime contract.

The implementation does not redesign the browser host transport. Instead it generates a conservative host_bridge_workflow script that:

1. preserves host bridge actions
2. preserves localhost host-runtime dependencies
3. lists callback business endpoints
4. invokes host bridge APIs when available
5. invokes callback endpoints through the existing browser request path
6. returns blocked/error/partial/ok artifact statuses instead of pretending full equivalence

Assets Updated

1. src/generated_scene/generator.rs
2. tests/scene_generator_test.rs

Contract

The minimal G6 contract is now:

1. at least one host_bridge workflow step
2. at least one callback_request workflow step
3. at least one business endpoint

If that contract is missing, generation still fails closed.

Validation

Executed:

cargo test --test scene_generator_test g6 -- --nocapture
cargo test --test scene_generator_test -- --nocapture
cargo test --test scene_generator_p1_family_test -- --nocapture
cargo test --test scene_generator_family_policy_test -- --nocapture
cargo test --test scene_generator_canonical_test -- --nocapture

All target regressions passed.

Result

G6 now has a minimum generated package path while retaining a fail-closed negative test for incomplete contracts.

The next runtime-contract target is G7 multi_endpoint_inventory.