---
source: crates/rolldown_devtools_metrics/src/tests.rs
expression: "render::render_entry(&report)"
---
# Build Metrics (devtools report mode)
Build 100.0 ms · output 5.6 kB · 6 modules (1 external) / 4 chunks / 5 assets / 3 packages · node / esm · build #1
1 plugin hook did no work in any call — a hook filter would skip those calls (`timing.md`, "Hooks that did no work")
## Details (load on demand)
| File | Load this when… |
| --- | --- |
| `metrics.json` | you need one precise number or the `delta`/`baselineDelta` sections — query it (jq/grep a metric id), don't read it wholesale |
| `timing.md` | investigating slow builds: stage split, plugin & hook cost, hooks that did no work |
| `chunks.md` | bundle size: chunk composition, reasons & cross-chunk duplication |
| `modules.md` | module graph: import kinds, most-imported, shared-across-entries |
| `packages.md` | dependency bloat: largest packages, direct/transitive, duplicate versions |
| `graph.md` | code-splitting: entry points, chunk import graph & initial-load cost |
| `module-graph.json` | what-if queries: the bytes one deferred import removes from the initial load — filter it, don't read it wholesale |
| `chunk-graph.json` | joining output file names to browser request timings (every chunk, no top-N limit) |
| `history.jsonl` | trends: one summary line per build |
| `AGENTS.md` | the directory contract: files, metric ids, experiment workflow |
> Derived in-memory from the rolldown devtools event stream (same data that feeds Vite DevTools). Durations are measured at event emission. Sizes are per asset/chunk, per package and per module (rendered bytes before minification).