Distributors and pricing - agentee reference

agentee parts: BOM pricing at Mouser and Farnell and cheaper parts that drop in without a downgrade.

agentee parts NAME (MCP parts) prices the BOM of a layout or schematic at Mouser and Farnell and lists cheaper parts that drop in. The keys live outside every project, in ~/.config/agentee/distributors.toml ($AGENTEE_DISTRIBUTORS or --config point elsewhere):

[mouser]
api_key = "..."                # Mouser Search API key, not the Cart/Order key

[farnell]
api_key = "..."                # element14 Product Search API key
store = "uk.farnell.com"       # ie.farnell.com, de.farnell.com, www.newark.com, au.element14.com ...
# currency = "GBP"             # default follows the store

agentee parts buggy-guard --boards 5
agentee parts buggy-guard --distributor farnell --farnell-store ie.farnell.com
agentee parts buggy-guard --refs C11,R8 --json
agentee parts buggy-guard --no-alternatives

Each BOM line is one mpn field, the same grouping as bom.csv, needing its reference count times --boards. The line's offers are the distributor listings of that part number; the chosen one is the cheapest that is in stock for the quantity and not obsolete. A cost honours the listing's minimum and multiple and buys up to a later price break when the larger quantity costs less in total, so ten resistors may be bought as a hundred.

Alternatives, at most three per line, cheapest saving first, in the chosen offer's currency:

part	searched by	must keep
resistor, `R` on an `R_0603...` style footprint	value, tolerance and size	resistance within 0.5 %, tolerance no looser, the same imperial case code; thermistors, arrays and jumpers are refused
ceramic capacitor, `C` on a `C_0603...` footprint	value, voltage, dielectric and size	capacitance within 1 %, voltage no lower (from the value's `/50V` or the listed part), dielectric no worse (C0G stays C0G, X7R may become X7S or X8R, X5R may become X7R), tolerance no looser, the same case code; electrolytic, tantalum, polymer and film are refused
generic discrete, `D` or `Q` whose value is a JEDEC name (2N7002, BSS138, 1N4148, BAT54, BZT52, S1x, SS1x, SMAJ, BC847 ...)	name and package	the name inside the part number and the same package (SOT-23 is not SOT-23-5, SMA is DO-214AC, not SMB)
indicator LED, `D` on an `LED_0603...` footprint	colour and size	the colour and the case code
anything else	nothing	only the same part at the other distributor, and the distributor's suggested replacement

Case codes are read from the imperial attribute (Case Code - in) or the part of a Farnell value before its [... Metric], so a 0201 listed as 0201 [0603 Metric] is not taken for an 0603. The report ends with the total per currency as chosen and with every cheaper pick, and the number of API calls made: Mouser allows 30 a minute and 1000 a day, and the part lookups go ten part numbers to a call. A refused key is reported once and that distributor is not asked again in the run.