[P0][Runtime Bridge] Resolve the canonical simplicio binary and verify MCP capabilities before effects

[wesleysimplicio]

Objective

Make the Loop RuntimeBridge start the actual published Runtime binary reliably on clean installations and fail with actionable diagnostics before any effect is attempted.

The Runtime package publishes the executable named simplicio, while RuntimeBridge currently defaults to simplicio-runtime. This works only with an undocumented wrapper or SIMPLICIO_RUNTIME_BIN override.

Implementation steps

1. Define canonical binary resolution order: explicit constructor value, SIMPLICIO_RUNTIME_BIN, installed simplicio, then documented legacy aliases.
2. Never resolve the Loop's own executable or an arbitrary PATH collision as Runtime.
3. Probe version and compiled identity before starting MCP.
4. Start simplicio serve --mcp --stdio --json and complete initialize/initialized.
5. Call capabilities/tools-list and require the exact tools needed by the requested execution route.
6. Validate MCP protocol version, Runtime version range, effect transaction schema and HBI/HBP compatibility.
7. Cache the verified binary identity per executable hash, invalidating on file replacement.
8. Add doctor output with resolved path, version, SHA, capabilities and exact repair command.
9. Preserve Runtime-optional Loop operation; only Runtime-backed routes require the binary.
10. Remove silent fallback when the user explicitly selected Runtime execution.

Tests

• PyPI-installed Runtime exposing only simplicio.
• Explicit valid/invalid SIMPLICIO_RUNTIME_BIN.
• Legacy alias available.
• PATH collision and wrong product identity.
• Old/incompatible Runtime version.
• Missing required MCP tool.
• MCP protocol mismatch and malformed tools/list.
• Paths with spaces and Windows executable suffix.
• Binary replaced while a session is alive.
• Clean Linux/macOS/Windows fixtures.

Acceptance criteria

• Default clean installation resolves simplicio without an environment override.
• The exact executable identity and SHA are recorded in the run receipt.
• Missing/incompatible Runtime fails before mutation with one exact repair instruction.
• Runtime-optional Loop paths remain usable without Runtime.
• Explicit Runtime selection never silently falls back to direct subprocess execution.
• Capability negotiation is versioned and tested.
• No orphan process remains after probe failure.
• Local/container tests require no paid GitHub Actions.

Relations

• Runtime machine-readable manifest: wesleysimplicio/simplicio-runtime#3043
• Runtime warm path: wesleysimplicio/simplicio-runtime#2983

[wesleysimplicio]

Progress receipt: PR #707 merged as �7b9f76c. Local evidence: py_compile, git diff --check, and 14 focused runtime adapter/binary tests passed. The requested Qwen model file was locally validated at C:\Users\Z0059V7A\.simplicio\models\qwen3.5-4b-code-forged-Q4_K_M.gguf (model check: valid). Issue remains open for full production bridge wiring and installed-path evidence.

[wesleysimplicio]

CLAIMED

Worker: Codex / current simplicio-loop skill
Run: issue-692-runtime-bridge-20260723
Attempt: 1
Goal: Extend the canonical Runtime binary/MCP preflight toward production bridge wiring and capability verification for #692, with focused tests and local delivery evidence.
Worktree: C:\Users\Z0059V7A\m\repos\work\simplicio-loop-issue-692
Base: origin/main @ df9b8e3

I will re-query this issue and PR state before delivery; GitHub Actions are optional per the task.

[wesleysimplicio]

CLAIMED (canonical identity correction)

Worker: Codex / current simplicio-loop skill
Run: issue-692-runtime-bridge-20260723
Attempt: 1
Branch: codex/issue-692-runtime-bridge
Goal: Extend the existing canonical Runtime binary/MCP preflight toward production bridge wiring and capability verification for #692, with focused tests and local delivery evidence.

[wesleysimplicio]

MEASURED|Local Runtime preflight receipt (2026-07-23): canonical binary C:\Users\Z0059V7A\.local\simplicio-runtime\bin\simplicio-runtime.exe started the MCP initialize handshake successfully.

UNVERIFIED|Read-only probes simplicio_status and simplicio_fs_stat returned unknown tool; a direct tools/list response was invalid JSON. Therefore the installed binary/capability contract is not yet proven for Loop effects. Issue remains open until a compatible capability receipt is measured. GitHub Actions were intentionally ignored.

[wesleysimplicio]

MEASURED|Local Runtime preflight: canonical binary C:\Users\Z0059V7A.local\simplicio-runtime\bin\simplicio-runtime.exe started MCP initialize. UNVERIFIED|Read-only probes simplicio_status and simplicio_fs_stat returned unknown tool; direct tools/list was invalid JSON. Issue remains open until compatible capability receipt is measured. GitHub Actions ignored.

[wesleysimplicio]

MEASURED|Delivery receipt: PR #719 (#719) is merged into main at 2c5e47e from 34b53d0.

MEASURED|This slice adds canonical binary resolution (explicit path, SIMPLICIO_RUNTIME_BIN, installed simplicio, legacy alias), version/compiled-identity/SHA probing before process creation, MCP initialize + initialized + tools/list preflight, fail-closed required-tool checks, preflight receipts on effect transactions, and cache invalidation by executable identity. The #691 workspace-session conflict was resolved in the merged branch.

MEASURED|Local focused validation: 25 passed; runtime_binary coverage 90%, runtime_bridge coverage 55%, combined 65%; py_compile passed; git show --check passed. GitHub Actions were optional and not used as a delivery gate.

UNVERIFIED|Issue #692 remains OPEN because the installed Runtime still needs a compatible production capability manifest/receipt: the live probe reported simplicio_status and simplicio_fs_stat as unknown tools and an invalid direct ools/list response. Remaining work is the installed cross-platform capability/E2E evidence and Runtime-owned HBI/HBP manifest compatibility; no closure is claimed until those criteria are measured.