[rossirpaulo]

Summary

This PR implements the staged trace-backed boundary value ingestion work through Phase 7:

• establishes BoundaryId as the execution/history identity and threads boundary context through native, WASM, and playground paths
• captures root values, logs, per-call outputs/errors, and explicit call inputs through TraceHeap snapshots instead of retaining live BEX heap state
• persists boundary history as .bamlprof structure plus .bamlvalue value records, with replay/open/history support in native and warm-session WASM paths
• keeps readValue(boundaryId, valueRef) as the single hydration path for live and replayed values
• adds boundary-local SHA-256 blob storage for large value bodies while leaving small records inline
• ensures process-local handles, host-owned objects, and opaque values are represented as safe omissions/descriptors rather than raw handle keys in durable artifacts
• supports model-generated image values by copying MediaValue RustData into trace-owned media snapshots and encoding them as BamlValueMedia

Why

Boundary traces need durable, replayable value artifacts without holding onto mutable VM heap pointers, CFFI handle-table keys, JS/Python registry entries, or other process-local state. The new pipeline separates hot structural tracing from cold value ingestion: capture copies BAML-visible values into TraceHeap, value consumers encode artifact-safe bytes, .bamlvalue/blob storage owns the body data, and the UI hydrates lazily via readValue.

Validation

Automated checks run across the phase stack include:

• cargo test --manifest-path baml_language/Cargo.toml -p bex_events ids
• cargo test --manifest-path baml_language/Cargo.toml -p bex_events run_store
• cargo test --manifest-path baml_language/Cargo.toml -p bex_events history
• cargo test --manifest-path baml_language/Cargo.toml -p bex_events log
• cargo test --manifest-path baml_language/Cargo.toml -p bex_events blob -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bex_events value -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bex_engine trace_heap -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bex_engine value_capture
• cargo test --manifest-path baml_language/Cargo.toml -p bex_engine trace_value -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bex_engine --test identity
• cargo test --manifest-path baml_language/Cargo.toml -p bex_engine --test prof_gate
• cargo test --manifest-path baml_language/Cargo.toml -p bridge_ctypes artifact_safe -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bridge_ctypes handle_table -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bex_heap trace_owned -- --nocapture
• cargo test --manifest-path baml_language/Cargo.toml -p bridge_cffi host_value -- --nocapture
• cargo check --manifest-path baml_language/Cargo.toml -p baml_lsp_server
• cargo check --manifest-path baml_language/Cargo.toml -p bridge_wasm --target wasm32-unknown-unknown
• pnpm --filter @b/pkg-proto test
• pnpm --filter @b/pkg-playground test
• git diff --check

Manual verification included native playground runs for boundary identity, history replay, root values, logs, explicit input snapshots, and Phase 7 image/blob behavior. The final Phase 7 browser check generated an image through ai-gateway-images / google/imagen-4.0-fast-generate-001; the playground rendered image (image/png) and persisted the large generated body as a SHA-256 blob while keeping the .bamlvalue record small.

Summary by CodeRabbit

• New Features
  • Added boundary-based addressing to the Playground WebSocket, including history browsing and ReadValue support.
  • Introduced boundary-local ID capabilities (current/new/capture) and expanded trace value/log capture surfaces.
• Bug Fixes
  • Improved $id/identity tracking and error tracing with correct rethrow behavior.
  • Enhanced call/throw handling so runtime identity and captured outcomes stay consistent across execution paths.
• Chores
  • Updated toolchain status output to include rustup-style “from …” annotations for clearer install/version information.

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Project	Deployment	Actions	Updated (UTC)
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[github-actions]

⏭️ Performance benchmarks were skipped

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To run them on this PR, do any of the following, then push a commit (or re-run CI):

• Add RUN_CODSPEED=1 to the PR description, or
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📝 Walkthrough

Walkthrough

BoundaryId replaces runId across identity, run records, VM call execution, capture routing, history storage, and playground APIs. The compiler and bytecode layers also add runtime_id and rethrow handling, while toolchain output and release verification are updated.

Changes

BoundaryId, runtime_id, capture, history, and playground v2

Layer / File(s)	Summary
Boundary identity and builtin wiring baml_language/crates/baml_builtins2/baml_std/boundary/*, baml_language/crates/baml_builtins2/src/lib.rs, baml_language/crates/baml_compiler2_hir/{Cargo.toml,src/package.rs}, baml_language/crates/bex_events/src/ids.rs, baml_language/crates/bex_events/src/lib.rs	BoundaryId and RuntimeId::Boundary are introduced, the boundary builtin package is registered, and builtin/package dependency checks are updated around the new boundary root.
TIR, MIR, and bytecode runtime ids baml_language/crates/baml_compiler2_tir/src/builder.rs, baml_language/crates/baml_compiler2_mir/src/{builder.rs,ir.rs,lower.rs,optimize.rs,pretty.rs}, baml_language/crates/baml_tests/projects/diagnostic_errors/runtime_id_misuse/runtime_id.baml, baml_language/crates/baml_compiler2_emit/src/{analysis.rs,emit.rs,lib.rs,stack_carry.rs}, baml_language/crates/bex_vm_types/src/bytecode.rs, baml_language/crates/bex_vm/{src/debug.rs,tests/load_type.rs,tests/method_class_type_args.rs}, baml_language/crates/baml_tests/src/engine.rs	$id is split from normal arguments, MIR terminators carry optional runtime_id fields and Rethrow, and compiler lowering, optimization, emission, stack simulation, and pretty printing propagate those operands.
VM boundary helpers and capture dispatch baml_language/crates/bex_vm/{src/lib.rs,src/vm.rs,src/package_baml/*,src/package_boundary/*,tests/events.rs}	The VM adds boundary-local id helpers, runtime-id-aware dispatch, capture masks, and event source-location plumbing.
Engine trace capture and value queues baml_language/crates/bex_engine/{Cargo.toml,src/function_call_context.rs,src/lib.rs,src/trace_heap.rs,src/trace_value_encode.rs,src/value_capture.rs,tests/{identity.rs,prof_gate.rs}}, baml_language/crates/bex_heap/src/accessor.rs	Boundary-scoped function call contexts, trace heap snapshots, and producer-side capture queues are added, with tests covering boundary ids, captured values, and rethrow and origin behavior.
Value file format and artifact-safe encoding baml_language/crates/bex_events/{Cargo.toml,build.rs,src/value/*}, baml_language/crates/bridge_ctypes/src/{handle_table.rs,value_encode.rs}	The .bamlvalue schema, record model, readers, writers, blob artifacts, live cache, and artifact-safe bridge encoding are added.
Run store and history replay baml_language/crates/bex_events/src/{lib.rs,run.rs,run_wire.rs,history/*,prof/*}	Run records move to BoundaryId and value refs, wire JSON emits boundary and value fields, and history writers and replay reconstruct runs from stored profile and value segments.
Playground protocol v2 baml_language/crates/baml_lsp_server/{Cargo.toml,src/playground_{env,io,runs,server,ws}.rs}	Playground WebSocket messages and server handlers switch to boundaryId addressing, add history and value reads, and thread capture-enabled boundary runs through the server.

Workspace wiring and release support

Layer / File(s)	Summary
Workspace re-exports and pack-host features baml_language/crates/{bex_project/src/lib.rs,baml_pack_host/Cargo.toml,bex_vm_types/src/lib.rs}	Project re-exports and pack-host feature wiring are adjusted for the new engine and host package layout.
Selector annotations and release verification baml_language/crates/{baml/src/main.rs,baml_release/src/lib.rs}, .github/workflows/size-gate.reusable.yaml, baml_language/.cargo/size-gate.toml, baml_language/.ci/size-gate/*	Toolchain status output gains selector annotations, release downloads verify checksums before archive layout validation or binary extraction, and size-gate reporting and baselines are refreshed.

Sequence Diagram(s)

sequenceDiagram
  participant Client
  participant PlaygroundServer
  participant BexEngine
  participant TraceCaptureProducer
  participant HistoryStore
  participant LiveValueStore
  Client->>PlaygroundServer: FunctionRun / TestRun
  PlaygroundServer->>BexEngine: call with BoundaryId
  BexEngine->>TraceCaptureProducer: capture inputs, logs, outputs
  BexEngine-->>PlaygroundServer: outcome and queued captures
  PlaygroundServer->>TraceCaptureProducer: drain captured values
  TraceCaptureProducer->>HistoryStore: append value or log bodies
  TraceCaptureProducer->>LiveValueStore: retain live value body
  Client->>PlaygroundServer: ReadValue(boundaryId, valueRef)
  PlaygroundServer->>LiveValueStore: get value body
  PlaygroundServer->>HistoryStore: read_value_result fallback
  PlaygroundServer-->>Client: ValueBody

Loading

Estimated code review effort

🎯 5 (Critical) | ⏱️ ~120 minutes

Possibly related PRs

• BoundaryML/baml#3154: Both PRs modify the bex_engine call-context plumbing (notably baml_language/crates/bex_engine/src/function_call_context.rs and how call_function/LSP/playground paths construct/pass FunctionCallContext).
• BoundaryML/baml#3316: The main PR’s MIR/VM throw–catch handling changes, including Rethrow and exception unwinding, are tightly coupled with the same exception-flow areas.
• BoundaryML/baml#3740: Both PRs work on the same BoundaryId / $id identity surface across compiler, VM, engine, and tests.
• BoundaryML/baml#3786: Both PRs migrate playground run handling toward the run-store and websocket boundary-addressing flow.

Suggested reviewers

• antoniosarosi

Poem

I hopped by moonlit BoundaryId rows,
where tiny $id carrots glow.
I tucked live bytes in history hay,
and watched rethrows hop away.
Hop hop — the playground pings with glee 🐰

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: trace-backed boundary value artifacts plus history support.
Docstring Coverage	✅ Passed	Docstring coverage is 99.43% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch paulo/data-ingestion

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[github-actions]

Binary size checks passed

✅ 7 passed

	Artifact	Platform	File	Gzip	Gated on	Baseline	Delta	Status
✅	baml-cli	Linux	🔒 21.5 MB	9.2 MB	file	21.5 MB	+12.0 KB (+0.1%)	OK
✅	packed-program	Linux	🔒 15.6 MB	6.6 MB	file	15.6 MB	+0 B (+0.0%)	OK
✅	baml-cli	macOS	🔒 16.5 MB	8.0 MB	file	16.1 MB	+447.2 KB (+2.8%)	OK
✅	packed-program	macOS	🔒 12.0 MB	5.7 MB	file	12.0 MB	+50.2 KB (+0.4%)	OK
✅	baml-cli	Windows	🔒 18.1 MB	8.2 MB	file	18.1 MB	+0 B (+0.0%)	OK
✅	packed-program	Windows	🔒 13.0 MB	5.8 MB	file	13.0 MB	+0 B (+0.0%)	OK
✅	bridge_wasm	WASM	14.3 MB	🔒 4.1 MB	gzip	4.1 MB	+3 B (+0.0%)	OK

🔒 = the size this artifact is GATED on (ceiling + delta). Binaries gate on file size (installed binary); WASM gates on gzip (download size). The other size is shown for information only.

---

Generated by cargo size-gate · workflow run

[coderabbitai]

Actionable comments posted: 1

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

baml_language/crates/bex_events/src/value/read.rs (1)

90-98: 🗄️ Data Integrity & Integration | 🟡 Minor | ⚡ Quick win

Also reject stray body/blob on capture-loss records.

The capture-loss guard rejects metadata, log_event, and capture, but not body or blob. A malformed/corrupted .bamlvalue capture-loss record carrying a body or blob is accepted and those fields are silently dropped, unlike the strict lifecycle path above (Lines 71-83). Tighten for consistency.

🛡️ Proposed fix

     if let Some(loss) = record.capture_loss {
-        if record.metadata.is_some() || has_log_event || record.capture.is_some() {
+        if record.metadata.is_some()
+            || has_log_event
+            || record.capture.is_some()
+            || !record.body.is_empty()
+            || record.blob.is_some()
+        {
             return Err(io::Error::new(
                 io::ErrorKind::InvalidData,
                 "value record mixed capture loss metadata with body metadata",
             ));
         }
         return Ok(ValueFileRecord::CaptureLoss(loss.try_into()?));
     }

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@baml_language/crates/bex_events/src/value/read.rs` around lines 90 - 98, The
capture-loss handling in read_value_record is too permissive because it rejects
metadata, log_event, and capture but still accepts stray body/blob fields, which
are then silently dropped. Tighten the guard in the if let Some(loss) =
record.capture branch to also reject any record where body or blob is present,
matching the stricter validation used in the normal lifecycle path and keeping
ValueFileRecord::CaptureLoss conversion only for clean capture-loss records.

🧹 Nitpick comments (1)

baml_language/crates/bex_events/src/history/router.rs (1)

77-83: 🚀 Performance & Scalability | 🔵 Trivial | ⚡ Quick win

record(id) is now an O(n) linear scan (regression from O(1)).

records is always sorted ascending by id (ids are assigned monotonically in ingest and only the oldest are drained from the front), so a binary search restores logarithmic lookup. This matters because routing claims records by id and the buffer can hold up to max_records (default 100_000), turning per-claim lookups into a potential O(n²) over a full buffer.

♻️ Use the sorted-by-id invariant

     #[must_use]
     pub fn record(&self, id: HistoryProfileRecordId) -> Option<&HistoryProfileRecord> {
-        self.records
-            .iter()
-            .find(|record| record.id == id)
-            .map(|record| &record.record)
+        self.records
+            .binary_search_by_key(&id, |record| record.id)
+            .ok()
+            .map(|index| &self.records[index].record)
     }

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@baml_language/crates/bex_events/src/history/router.rs` around lines 77 - 83,
`HistoryRouter::record` currently does a linear scan over `records`, which
regresses lookup performance; update this method to use the existing
sorted-by-`id` invariant and a binary search instead of `iter().find(...)`.
Locate the fix in `record(id)` and keep the return type/behavior unchanged by
returning the matched `HistoryProfileRecord` when the search succeeds,
preserving the current `Option<&HistoryProfileRecord>` API.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@baml_language/crates/bex_events/src/value/live_cache.rs`:
- Around line 158-170: The read path in LiveCache::get leaves stale tombstones
in lru on every cache hit, so the deque can grow without bound during repeated
reads. Update LiveCache to periodically compact/rebuild lru from the live
entries in sequence order when it grows too large relative to entries, and apply
the same cleanup to evicted_order since LiveCache::insert removes from evicted
without trimming that deque. Use the existing LiveValueKey, next_sequence, and
evict_until_within_budget flow to place the fix without changing lookup
behavior.

---

Outside diff comments:
In `@baml_language/crates/bex_events/src/value/read.rs`:
- Around line 90-98: The capture-loss handling in read_value_record is too
permissive because it rejects metadata, log_event, and capture but still accepts
stray body/blob fields, which are then silently dropped. Tighten the guard in
the if let Some(loss) = record.capture branch to also reject any record where
body or blob is present, matching the stricter validation used in the normal
lifecycle path and keeping ValueFileRecord::CaptureLoss conversion only for
clean capture-loss records.

---

Nitpick comments:
In `@baml_language/crates/bex_events/src/history/router.rs`:
- Around line 77-83: `HistoryRouter::record` currently does a linear scan over
`records`, which regresses lookup performance; update this method to use the
existing sorted-by-`id` invariant and a binary search instead of
`iter().find(...)`. Locate the fix in `record(id)` and keep the return
type/behavior unchanged by returning the matched `HistoryProfileRecord` when the
search succeeds, preserving the current `Option<&HistoryProfileRecord>` API.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 7e8711dd-c427-4040-8ec9-3ecf9668c3aa

📥 Commits

Reviewing files that changed from the base of the PR and between 07636ce and 11d20c1.

⛔ Files ignored due to path filters (1)

• baml_language/Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (30)

• baml_language/crates/baml/src/main.rs
• baml_language/crates/baml_compiler2_hir/Cargo.toml
• baml_language/crates/baml_compiler2_hir/src/package.rs
• baml_language/crates/baml_compiler2_mir/src/pretty.rs
• baml_language/crates/baml_lsp_server/src/playground_server.rs
• baml_language/crates/baml_pack_host/Cargo.toml
• baml_language/crates/baml_release/src/lib.rs
• baml_language/crates/bex_engine/src/trace_heap.rs
• baml_language/crates/bex_engine/src/trace_value_encode.rs
• baml_language/crates/bex_engine/src/value_capture.rs
• baml_language/crates/bex_engine/tests/prof_gate.rs
• baml_language/crates/bex_events/src/history/boundary_writer.rs
• baml_language/crates/bex_events/src/history/mod.rs
• baml_language/crates/bex_events/src/history/router.rs
• baml_language/crates/bex_events/src/value/artifact.rs
• baml_language/crates/bex_events/src/value/encode.rs
• baml_language/crates/bex_events/src/value/live_cache.rs
• baml_language/crates/bex_events/src/value/mod.rs
• baml_language/crates/bex_events/src/value/proto/bamlvalue.proto
• baml_language/crates/bex_events/src/value/read.rs
• baml_language/crates/bex_events/src/value/record.rs
• baml_language/crates/bex_events/src/value/writer.rs
• baml_language/crates/bex_project/src/lib.rs
• baml_language/crates/bex_vm/src/vm.rs
• baml_language/crates/bex_vm/tests/events.rs
• baml_language/crates/bridge_ctypes/Cargo.toml
• baml_language/crates/bridge_ctypes/src/handle_table.rs
• baml_language/crates/bridge_ctypes/src/lib.rs
• baml_language/crates/bridge_ctypes/src/value_encode.rs
• baml_language/crates/bridge_wasm/src/lib.rs

💤 Files with no reviewable changes (1)

• baml_language/crates/baml_pack_host/Cargo.toml

✅ Files skipped from review due to trivial changes (2)

• baml_language/crates/baml_compiler2_hir/Cargo.toml
• baml_language/crates/bex_project/src/lib.rs

🚧 Files skipped from review as they are similar to previous changes (13)

• baml_language/crates/bex_events/src/value/mod.rs
• baml_language/crates/baml/src/main.rs
• baml_language/crates/bex_events/src/value/proto/bamlvalue.proto
• baml_language/crates/baml_release/src/lib.rs
• baml_language/crates/baml_compiler2_mir/src/pretty.rs
• baml_language/crates/bex_engine/src/trace_heap.rs
• baml_language/crates/bex_events/src/history/boundary_writer.rs
• baml_language/crates/bex_events/src/value/artifact.rs
• baml_language/crates/bex_events/src/history/mod.rs
• baml_language/crates/bex_engine/tests/prof_gate.rs
• baml_language/crates/bex_events/src/value/record.rs
• baml_language/crates/baml_lsp_server/src/playground_server.rs
• baml_language/crates/bex_vm/src/vm.rs