diff --git a/plans/build-event-log.md b/plans/build-event-log.md
index f57563b..b39812a 100644
--- a/plans/build-event-log.md
+++ b/plans/build-event-log.md
@@ -245,3 +245,94 @@ GROUP BY br.status;
 ```
 
 The service layer builds higher-level operations on top of both the simple interface and direct SQL access.
+
+## 4. Core Build Implementation Integration
+
+### Command Line Interface
+
+The core build implementation (`analyze.rs` and `execute.rs`) will be enhanced with build event logging capabilities through new command line arguments:
+
+```bash
+# Standard usage with build event logging
+./analyze partition_ref1 partition_ref2
+./execute --build-event-log sqlite:///tmp/build.db < job_graph.json
+
+# With explicit build request ID for correlation
+./analyze --build-event-log postgres://user:pass@host/db --build-request-id 12345678-1234-1234-1234-123456789012
+```
+
+**New Command Line Arguments:**
+- `--build-event-log <URI>` - Specify persistence URI for build events (logging to stdout is implicit)
+  - `sqlite://path` - Persist to SQLite database file
+  - `postgres://connection` - Persist to PostgreSQL database
+- `--build-request-id <UUID>` - Optional build request ID (auto-generated if not provided)
+
+### Integration Points
+
+**In `analyze.rs` (Graph Analysis Phase):**
+1. **Build Request Lifecycle**: Log `BUILD_REQUEST_RECEIVED` when analysis starts, `BUILD_REQUEST_PLANNING` during dependency resolution, and `BUILD_REQUEST_COMPLETED` when analysis finishes
+2. **Staleness Detection**: Query build event log for existing `PARTITION_AVAILABLE` events to identify non-stale partitions that can be skipped
+3. **Delegation Logging**: Log `PARTITION_DELEGATED` events when skipping partitions that are already being built by another request
+4. **Job Planning**: Log `PARTITION_SCHEDULED` events for partitions that will be built
+
+**In `execute.rs` (Graph Execution Phase):**
+1. **Execution Lifecycle**: Log `BUILD_REQUEST_EXECUTING` when execution starts
+2. **Job Execution Events**: Log `JOB_SCHEDULED`, `JOB_RUNNING`, `JOB_COMPLETED/FAILED` events throughout job execution
+3. **Partition Status**: Log `PARTITION_BUILDING` when jobs start, `PARTITION_AVAILABLE/FAILED` when jobs complete
+4. **Build Coordination**: Check for concurrent builds before starting partition work to avoid duplicate effort
+
+### Non-Stale Partition Handling
+
+The build event log enables intelligent partition skipping:
+
+1. **During Analysis**: Query for recent `PARTITION_AVAILABLE` events to identify partitions that don't need rebuilding
+2. **Staleness Logic**: Compare partition timestamps with upstream dependency timestamps to determine if rebuilding is needed
+3. **Skip Documentation**: Log `PARTITION_DELEGATED` events with references to the existing build request ID that produced the partition
+
+### Bazel Rules Integration
+
+The `databuild_graph` rule in `rules.bzl` will be enhanced to propagate build event logging configuration:
+
+```python
+databuild_graph(
+    name = "my_graph",
+    jobs = [":job1", ":job2"],
+    lookup = ":job_lookup",
+    build_event_log = "sqlite:///tmp/builds.db",  # New attribute
+)
+```
+
+**Generated Targets Enhancement:**
+- `my_graph_analyze`: Receives `--build-event-log` argument
+- `my_graph_exec`: Receives `--build-event-log` argument  
+- `my_graph_build`: Coordinates build request ID across analyze/execute phases
+
+### Implementation Strategy
+
+**Phase 1: Infrastructure**
+- Add `BuildEventLog` trait and implementations for stdout/SQLite/PostgreSQL
+- Update `databuild.proto` with build event schema
+- Add command line argument parsing to `analyze.rs` and `execute.rs`
+
+**Phase 2: Analysis Integration**
+- Integrate build event logging into `analyze.rs`
+- Implement staleness detection queries
+- Add partition delegation logic
+
+**Phase 3: Execution Integration**
+- Integrate build event logging into `execute.rs`
+- Add job lifecycle event logging
+- Implement build coordination checks
+
+**Phase 4: Bazel Integration**
+- Update `databuild_graph` rule with build event log support
+- Add proper argument propagation and request ID correlation
+- End-to-end testing with example graphs
+
+### Key Benefits
+
+1. **Stdout Logging**: Immediate visibility into build progress with `--build-event-log stdout`
+2. **Persistent History**: Database persistence enables build coordination and historical analysis
+3. **Intelligent Skipping**: Avoid rebuilding fresh partitions, significantly improving build performance
+4. **Build Coordination**: Prevent duplicate work when multiple builds target the same partitions
+5. **Audit Trail**: Complete record of all build activities for debugging and monitoring