feat(bundle): rivet bundle <ID> --depth N --as {yaml,jsonl} (#206)

[avrabe]

Summary

Closes #206 — implements the rivet bundle <ID> --depth N --as {yaml,jsonl} CLI command, the rivet_bundle MCP tool, and the rivet-core/src/bundle.rs module. An LLM agent reasoning about an artifact and its neighbours can now get the full link-graph closure in one round-trip instead of N — closing the gap the issue body identified after Karpathy's LLM Wiki.

What changed

• rivet-core/src/bundle.rs (new). Breadth-first, visit-once traversal over Store::get + Artifact::links, returning a depth-stamped Vec<BundleEntry>. Cycles terminate via the visited set. Depth 0 = root only; depth 1 = root + direct neighbours. Dangling targets (links pointing outside the store) appear as target: references inside the parent's links: list but are not expanded.
• BundleFormat::{Yaml, Jsonl} rendering. YAML is hand-rendered (not serde_yaml) because the # satisfies -> REQ-002 inline annotations are the whole point of the format and serde can't round-trip comments. JSONL is one serde_json record per line for tool consumers / streaming readers.
• rivet-cli/src/main.rs — new Command::Bundle { id, depth, format } variant with --depth (default 1) and --as (default yaml). Handler cmd_bundle loads the project context, calls bundle::bundle, prints the rendered output. Invalid --as values produce a clear error listing the valid options.
• rivet-cli/src/mcp.rs — new rivet_bundle MCP tool with BundleParams { id, depth, format }. Defaults match the CLI. Returns the rendered bundle as text content.

Acceptance — issue #206 (lifted from the 2026-04-26 + 2026-05-09 triage comments)

• New module rivet-core/src/bundle.rs with closure traversal over Store + Link graph, depth-bounded — bundle::bundle(), lines 90–122.
• rivet bundle <ID> --depth N --as {yaml,jsonl} CLI command — Command::Bundle variant + cmd_bundle handler.
• MCP tool rivet_bundle so agents call this without shelling — mcp.rs, decorated #[tool(...)] on rivet_bundle.
• Output carries inline link annotations (# satisfies -> REQ-004 style) — proven by bundle_depth_one_yaml_with_annotations (CLI) and test_rivet_bundle_yaml_depth_one (MCP).
• Snapshot/regression test fixture: depth-0 → only root; depth-1 → root + neighbours; depth-2 → two-hop closure — depth_zero_returns_root_only, depth_one_returns_root_plus_neighbours, depth_two_includes_two_hop_closure in bundle::tests.
• Cycle handling tested (artifact A → B → A does not loop) — cycle_terminates.
• Markdown rendering explicitly out of scope per the issue body.
• Commit trailer Implements: REQ-007 (CLI) and Refs: FEAT-010 (MCP) — present.

Test plan

• cargo test -p rivet-core --lib — 931 pass (920 prior + 11 new bundle::tests).
• cargo test -p rivet-cli --test cli_commands — 66 pass (61 prior + 5 new bundle tests: depth-0 root only, depth-1 + annotations, jsonl shape, missing-root non-zero exit, invalid-format rejection).
• cargo test -p rivet-cli --test mcp_integration — 24 pass (22 prior + 2 new bundle tests; tools-list count test bumped 15 → 16 to register rivet_bundle).
• cargo clippy --workspace --all-targets -- -D warnings — clean.
• cargo fmt --all -- --check — clean.
• cargo run --release -p rivet-cli -- validate — 6 errors / 140 warnings / 0 broken cross-refs — byte-identical to pristine main. The 6 errors live in the spar: external fixture and are unaffected.
• cargo run --release -p rivet-cli -- docs check — PASS (47 files scanned, 0 violations).
• CI on this PR — verified by GHA.

Out of scope

• Markdown rendering, per the issue body's "Out of scope" section. YAML preserves typed structure with zero information loss; markdown would re-introduce ambiguity rivet's typed model exists to remove.
• docs/getting-started.md deep-dive on bundle — left for a docs-only follow-up so the surface lands first and stays focused (one-PR-per-issue rule).

🤖 Generated with Claude Code — issue-triage agent run 2026-05-09.

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Generated by Claude Code

[github-actions]

📐 Rivet artifact delta

No artifact changes in this PR. Code-only changes (renderer, CLI wiring, tests) don't touch the artifact graph.

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Rivet Criterion Benchmarks'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 1cdcc18	Previous: 6dfdca6	Ratio
store_insert/10000	14314238 ns/iter (± 1141835)	10777546 ns/iter (± 201358)	1.33
link_graph_build/10000	32984738 ns/iter (± 2919346)	22905310 ns/iter (± 293676)	1.44
validate/10000	16249974 ns/iter (± 1401829)	12167984 ns/iter (± 144437)	1.34

This comment was automatically generated by workflow using github-action-benchmark.

[codecov]

Codecov Report

❌ Patch coverage is 97.65625% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
rivet-core/src/bundle.rs	97.65%	6 Missing ⚠️

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