Bom

BOM Management

BOM data lives in KiCad schematic symbol properties as the single source of truth. This skill orchestrates the full lifecycle: analyze the schematic, search distributors, validate parts, write properties back, export tracking CSVs, and generate order files.

Related Skills

Scripts

Use <skill-path> to reference the BOM skill directory.

# Analyze schematic (JSON output, recursive sub-sheets)
python3 <skill-path>/scripts/bom_manager.py analyze path/to/schematic.kicad_sch --json --recursive

# Export BOM tracking CSV (creates new or merges with existing)
python3 <skill-path>/scripts/bom_manager.py export path/to/schematic.kicad_sch -o bom/bom.csv --recursive

# Generate per-distributor order files (5 boards + 2 spares/line)
python3 <skill-path>/scripts/bom_manager.py order bom/bom.csv --boards 5 --spares 2

# Quick single-distributor order (bypasses Chosen_Distributor column)
python3 <skill-path>/scripts/bom_manager.py order bom/bom.csv --distributor digikey

# Write properties to schematic (dry-run first, then apply)
echo '{"R1": {"MPN": "RC0805FR-0710KL", "Manufacturer": "Yageo"}}' \
  | python3 <skill-path>/scripts/edit_properties.py path/to/schematic.kicad_sch --dry-run

# Sync datasheet URLs from manifest.json back into schematic Datasheet properties
python3 <skill-path>/scripts/sync_datasheet_urls.py path/to/schematic.kicad_sch --recursive --dry-run

# Translate KiCad/Altium BOM and CPL files into JLCPCB upload format
# (`pnp --bom` filter drops orphan designators — see skills/jlcpcb/SKILL.md
# for the 3-step PCBA upload workflow)
python3 <skill-path>/scripts/translate_bom_pnp.py bom input_bom.csv -o jlc_bom.csv
python3 <skill-path>/scripts/translate_bom_pnp.py pnp input_cpl.csv -o jlc_cpl.csv --bom jlc_bom.csv

Workflow

Skip steps that don't apply. Common shortcuts:

• "Add Mouser PNs" — search Mouser by MPN for each part → validate → write to schematic → update CSV
• "Fill in the gaps" — run analyzer with --gaps-only, address each missing field
• "Update datasheet URLs" — run sync_datasheet_urls.py to backfill empty Datasheet fields from the datasheets manifest
• "Prepare for production" — ensure every part has an LCSC number, check stock, set Chosen_Distributor to LCSC

Step 1: Understand the Project

python3 <skill-path>/scripts/bom_manager.py analyze path/to/schematic.kicad_sch --json --recursive

The output tells you the project's field naming convention, which distributors are populated, what's missing, and the preferred distributor. Also look for an existing BOM tracking CSV in the project directory or bom/ folder.

The script covers common patterns, but some projects use internal key systems or parametric fields. See references/part-number-conventions.md for the full catalog. Read the schematic if something seems off.

Step 2: Sync Datasheets

Do this immediately. Datasheets are essential context for validation and part selection. Run the preferred distributor's sync first; if some fail, try others — they share the same datasheets/ directory and skip already-downloaded parts.

python3 <digikey-skill-path>/scripts/sync_datasheets_digikey.py path/to/schematic.kicad_sch --recursive
python3 <lcsc-skill-path>/scripts/sync_datasheets_lcsc.py path/to/schematic.kicad_sch --recursive
python3 <element14-skill-path>/scripts/sync_datasheets_element14.py path/to/schematic.kicad_sch --recursive

DigiKey is best (direct PDF URLs). element14 is reliable (no bot protection). LCSC works for LCSC-only parts. Mouser is a last resort (often blocks downloads).

Tell the user where datasheets are (e.g., hardware/<project>/datasheets/). They'll reference them often.

Cross-revision projects: Use a single shared datasheets directory at the project level rather than per-revision. The same MPN's datasheet doesn't change between revisions.

Re-sync after writing new MPNs (Step 5) — the scripts are idempotent. Then backfill Datasheet URLs into the schematic:

python3 <skill-path>/scripts/sync_datasheet_urls.py path/to/schematic.kicad_sch --recursive

This reads datasheets/manifest.json (legacy name index.json still supported) and writes discovered datasheet URLs into empty schematic Datasheet properties. Opportunistic — only fills blanks. If a schematic already has a different URL, it warns about the mismatch without overwriting (use --overwrite to replace). Run with --dry-run first to preview.

Step 3: Gather Part Information

Watch for comma-separated MPNs. Some symbols track multiple physical parts (e.g., battery holder + clip). Split on commas and search each MPN independently — searching the combined string matches the wrong product.

Search strategy based on what's available:

• Has MPN → search distributors by MPN to get their PNs and stock
• Has distributor PN but no MPN → search that distributor, get MPN, then search others
• Has only Value + Footprint → search by description (e.g., "100nF 0402 X7R 16V")

Use the project's preferred distributor first, then alternates. Prototype: DigiKey primary, Mouser secondary. Production: LCSC.

Step 4: Validate Matches

Don't assume existing PNs are correct — distributor PNs go stale (discontinued, renumbered). Verify existing PNs resolve against the API. If a PN returns 404, flag it for replacement.

For every match, verify:

1. Package matches the schematic footprint (see cross-reference table below)
2. Specs match (capacitance, resistance, voltage, tolerance)
3. Description makes sense (a resistor ref should get a resistor)
4. Lifecycle — not obsolete or EOL
5. Datasheet URL is a direct PDF link (not a product page)

If ambiguous, ask the user. A wrong part is worse than a missing part.

Step 5: Update the Schematic

KiCad coexistence. The script detects KiCad's lock file and warns but proceeds. KiCad doesn't auto-detect external changes — it keeps its in-memory copy. If KiCad is open, tell the user: "Close and reopen the schematic (File → Open Recent) to see the changes. Don't save from KiCad first."

If unsaved KiCad work exists, ask them to save first (Ctrl+S), then run the script, then reopen.

echo '{"R1": {"MPN": "RC0805FR-0710KL", "Manufacturer": "Yageo", "DigiKey": "311-10.0KCRCT-ND"}}' \
  | python3 <skill-path>/scripts/edit_properties.py path/to/schematic.kicad_sch

Backups: By default, no .bak file is created (git tracks changes). Pass --backup if the schematic is not in a git repo or has uncommitted changes the user wants to preserve.

Respect the project's convention. Write to "Digi-Key_PN" if that's what exists, not "DigiKey". Use canonical names only for new projects.

Always write Manufacturer alongside MPN — every API returns it, it's free data.

Step 6: Update the BOM Tracking CSV

python3 <skill-path>/scripts/bom_manager.py export path/to/schematic.kicad_sch -o bom/bom.csv --recursive

CSV columns are dynamic — only distributors the project uses get columns. Base columns: Reference, Qty, Value, Footprint, MPN, Manufacturer. Each active distributor gets a PN column + stock column. Tail columns: Chosen_Distributor, Datasheet, Validated, DNP, Notes.