PR #1560 — Milestone v0.20.0 Cluster D — Next-Gen Harness Onboarding (Meta Muse Integration)

The Broader Goal at the End of the Previous PR

Advancing the multi-agent operating system toward reliable, autonomous development, unblocking workgroup velocity and eliminating manual developer toil.

Strategic Shifts in This PR

Focused, limited-treatment delta resolving PR #1560 requirements with strict backward compatibility and comprehensive verification.

What This PR Shipped

• Meta Muse Capability Baseline (synlynk/_constants.py, #1508):
• Added muse to HARNESS_CAPABILITY_BASELINES with full can_gh_write: True, non-interactive flags (run --non-interactive), prompt argument handling (--prompt), and builder, verifier, architect role charters.
• Defined NEXT_GEN_FLEET = frozenset({"muse"}) and updated EXTENDED_FLEET = frozenset({"local", "muse"}).
• Dispatch CLI Adapter & Prompt Formatting (synlynk/dispatch.py):
• Injected -C worktree_path and --output-format json flags into Muse subprocess dispatches.
• Formatted prompts with closed-loop SYNLYNK_TASK_RECEIVED digest header and working directory constraint blocks.
• Structured Token & Cost Extraction (synlynk/costs.py):
• Added _extract_muse_structured() to parse both single JSON and streaming JSON outputs with input_tokens, output_tokens, and cached_tokens.
• Probe & Documentation (synlynk/probe.py, docs/harness-capability-baseline.md):
• Mapped muse in harness_map for synlynk probe muse verification.
• Documented Meta Muse architecture and capability profile.

Verification & Test Evidence

5 unit tests in tests/test_muse_harness.py covering TC-0 schema compliance, flag generation, prompt formatting, token extraction, and probing. 147 dispatch tests and 26 probe tests verified green.

What This Achieved on the Path to Autonomy

Maintains repository integrity, expands test-proven capabilities, and keeps the hybrid human-agent workgroup aligned with zero drift.