Spectra v0.4: Adaptive Context Runtime

[Azakeen]

Summary

Ships Spectra v0.4 as an adoption-focused adaptive context runtime centered on the default spectra_context MCP tool while preserving all v0.3 tools and persisted schema compatibility.

What changed

• Adds deterministic intent routing, generic evidence ranking, semantic token budgeting, atomic packet packing, bounded source windows, and stale-safe continuation cursors.
• Adds session-scoped privacy-safe receipts, local aggregate efficiency metrics, spectra context, and spectra stats.
• Defaults MCP discovery to spectra_context; legacy tools remain available through SPECTRA_MCP_TOOLS.
• Adds the frozen 20-repository/100-task v0.4 holdout, report gate, and resumable Grok evaluator.
• Adds cross-platform release packaging, SHA-256 checksums, Sigstore signing/provenance, installers, and Homebrew/Scoop manifest generation.
• Corrects the pilot findings by budgeting the complete rendered packet and limiting the evaluation harness to the initial packet plus one follow-up.

Impact

LLM harnesses receive compact, deduplicated, text-first context through one drop-in tool. Existing index-v4, ledger-v1, lifecycle-v1, hook installations, MCP commands, allowlists, and legacy response contracts remain compatible.

Evaluation

The preserved Grok 4.5 pilot covered 100 paired tasks across 20 pinned repositories. Before the final corrections it measured 60.4% lower median provider input, 55.0% lower input at p75, 95.4% fewer repeated context bytes, and deterministic success improving from 57% to 77%. The original pilot missed the call-count and packet-budget gates; those implementations now have targeted regression coverage, but the paid corpus was intentionally not rerun. The formal multi-provider/multi-harness release gate remains future work.

Validation

GitHub Actions run 29782073255 passed on commit 2fdcc80:

• formatting and Clippy with warnings denied
• full locked workspace tests
• serialized locked workspace tests
• release workspace build
• macOS, Ubuntu, and Windows

Release tag: v0.4.0.

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