Compare alternatives and trace Brightway supply chains

list_projects
→ list_databases(project=...)
→ search_activities(project=..., database=..., query=...)
→ list_methods(project=..., filter=...)

Reuse returned activity codes and method tuples. Do not reconstruct identifiers from display names.

run_multi_method(
  project="...",
  database="...",
  code="...",
  methods=[[...], [...]],
  amount=1.0
)

Use this when the activity and functional amount stay fixed while the impact method changes. Use run_multi_method_async for larger method sets.

compare_activities(
  project="...",
  alternatives=[
    {"database": "foreground", "code": "option_a", "label": "Option A"},
    {"database": "foreground", "code": "option_b", "label": "Option B"}
  ],
  methods=[[...]]
)

Use compare_activities_async for a large alternatives × methods grid.

run_lca(...)
→ contribution_analysis(result_id=...)
→ top_emissions(result_id=...)
→ dispose_result(result_id=...)

Keep the same result_id for contribution and emission analysis so every view refers to the same solved LCA.

supply_chain(
  project="...",
  database="...",
  code="...",
  method=[...],
  amount=1.0,
  max_level=3,
  cutoff=0.02
)

max_level limits recursion depth and cutoff removes small contribution branches. Use supply_chain_async for larger graphs.

The Brightway MCP repository tests this workflow with a synthetic foreground: electricity emits 0.9 kg CO2-eq/kWh; steel uses 2.5 kWh plus 1.8 kg direct CO2-eq/kg; widget uses 0.5 kg steel + 1 kWh; widget_lite uses 0.3 kg steel + 1 kWh.

steel = 1.8 + 2.5 × 0.9 = 4.05 kg CO2-eq/kg
widget = 0.5 × 4.05 + 0.9 = 2.925 kg CO2-eq
widget_lite = 0.3 × 4.05 + 0.9 = 2.115 kg CO2-eq

The automated comparison test asserts that widget_lite scores lower. The supply-chain test also asserts a root share of 1.0 with steel and electricity branches present.

A contribution tree explains the score produced by the selected Brightway model. It does not establish a valid functional basis, database choice, allocation rule, LCIA method, or intervention strategy.