elicit_uom

MCP shadow crate for uom 0.38 — provides ~55 Model Context Protocol tools across two plugins for dimension-safe quantity arithmetic, unit conversion, and Rust code generation.

Plugins

`UomQuantityPlugin` — `uom_{registration}__` + `uom_qty__` (~40 tools)

Stores live uom::si::f64::* quantities server-side using the Phase 3F.6 multi-parameter factory pattern. Every registration gets its own typed HashMap<Uuid, Q> — no type erasure. A shared QuantityBus enables cross-registration arithmetic (Length / Time → Velocity) by routing through SI f64 values and the dimension derivation table.

`UomCodePlugin` — `uom_code__*` (~15 tools)

Pure code generation and catalog browsing. Uses the shared QuantityBus so emitted code reflects quantities created by UomQuantityPlugin.

Usage

use elicit_uom::{UomQuantityPlugin, UomCodePlugin};

let qty = UomQuantityPlugin::new();
let code = UomCodePlugin::with_bus(qty.bus());
// Register both plugins with your MCP server

`UomQuantityPlugin` tools

Per-registration tools (18 quantities × 2 = 36 tools)

Each registered quantity {reg} exposes two tools:

`uom_{reg}__new`

Create a new quantity from a value and unit string. Returns a UUID for subsequent use.

Param	Type	Description
`value`	`f64`	Numeric value in the given unit
`unit`	`String`	Unit string (e.g. `"kilometer"`, `"foot"`)

Returns { id: String, registration: String, si_value: f64, code_snippet: String }

`uom_{reg}__emit`

Emit Rust source code for one or more stored quantities of this type.

Param	Type	Description
`ids`	`Vec<String>`	UUIDs of quantities to include

Returns a Rust code string using uom::si::f64::*

Registered quantities (18)

Registration	uom Rust type	SI base unit	Example units
`length`	`Length`	meter	meter, kilometer, foot, inch, yard, mile, nautical_mile, light_year
`mass`	`Mass`	kilogram	kilogram, gram, pound, ounce, tonne
`time`	`Time`	second	second, millisecond, minute, hour, day, year
`temperature`	`ThermodynamicTemperature`	kelvin	kelvin, degree_celsius, degree_fahrenheit
`electric_current`	`ElectricCurrent`	ampere	ampere, milliampere, microampere
`amount_of_substance`	`AmountOfSubstance`	mole	mole, millimole
`luminous_intensity`	`LuminousIntensity`	candela	candela
`velocity`	`Velocity`	meter_per_second	meter_per_second, kilometer_per_hour, mile_per_hour, knot, speed_of_light
`acceleration`	`Acceleration`	meter_per_second_squared	meter_per_second_squared, foot_per_second_squared, standard_gravity
`force`	`Force`	newton	newton, kilonewton, pound_force, dyne
`energy`	`Energy`	joule	joule, kilojoule, kilocalorie, kilowatt_hour, electronvolt
`power`	`Power`	watt	watt, kilowatt, megawatt, horsepower
`pressure`	`Pressure`	pascal	pascal, kilopascal, bar, atmosphere, psi, torr
`frequency`	`Frequency`	hertz	hertz, kilohertz, megahertz, gigahertz
`area`	`Area`	square_meter	square_meter, hectare, acre, square_foot, square_mile
`volume`	`Volume`	cubic_meter	cubic_meter, liter, milliliter, gallon, pint, fluid_ounce
`density`	`MassDensity`	kilogram_per_cubic_meter	kilogram_per_cubic_meter, gram_per_cubic_centimeter
`angle`	`Angle`	radian	radian, degree, revolution, arcminute, arcsecond

Shared query tools (5)

Tool	Params	Description
`uom_qty__value`	`id, unit`	Extract value in any supported unit
`uom_qty__describe`	`id`	Registration, SI value, SI unit, code snippet
`uom_qty__list`	—	All stored quantities with registration and SI value
`uom_qty__delete`	`id`	Remove a stored quantity
`uom_qty__registration`	`id`	Get registration name (`"length"`, `"mass"`, etc.)

Arithmetic tools (12, via QuantityBus)

Dimension-aware: add/sub require matching registrations; mul/div derive the result registration from the dimension table (e.g. length / time → velocity).

Tool	Params	Description
`uom_qty__add`	`lhs_id, rhs_id`	Add two same-registration quantities
`uom_qty__sub`	`lhs_id, rhs_id`	Subtract
`uom_qty__mul`	`lhs_id, rhs_id`	Multiply — derives result (length × length → area)
`uom_qty__div`	`lhs_id, rhs_id`	Divide — derives result (length / time → velocity)
`uom_qty__neg`	`id`	Negate
`uom_qty__abs`	`id`	Absolute value
`uom_qty__scale`	`id, factor: f64`	Multiply by dimensionless scalar
`uom_qty__recip`	`id`	1/x (frequency → time, etc.)
`uom_qty__sqrt`	`id`	Square root (area → length)
`uom_qty__powi`	`id, n: i32`	Integer power (length² → area)
`uom_qty__compare`	`lhs_id, rhs_id`	Returns `"less"`, `"equal"`, or `"greater"`
`uom_qty__approx_eq`	`lhs_id, rhs_id, tolerance?`	Relative equality check

Dimension derivation table:

Operation	LHS	RHS	Result
mul	length	length	area
mul	area	length	volume
mul	mass	acceleration	force
mul	force	length	energy
mul	velocity	time	length
div	length	time	velocity
div	velocity	time	acceleration
div	energy	time	power
div	force	area	pressure
div	mass	volume	density
sqrt	area	—	length
powi(2)	length	—	area
recip	frequency	—	time

Convert tool (1)

Tool	Params	Description
`uom_qty__convert`	`id, to_unit`	Value in target unit (no new UUID)

`UomCodePlugin` tools

Emit tools (5)

Tool	Params	Description
`uom_code__emit_conversion`	`registration, value, from_unit, to_unit, var_name?`	Emit a single unit-conversion snippet
`uom_code__emit_calculation`	`lhs_id, op, rhs_id, result_var?`	Emit arithmetic using stored quantities (`op`: `add`, `sub`, `mul`, `div`)
`uom_code__emit_physics_formula`	`formula`	Emit a named physics formula stub
`uom_code__emit_main`	`ids, display_style?`	Emit a complete `fn main()` for the given quantity UUIDs
`uom_code__emit_snippet`	`ids, units?`	Emit let-bindings for one or more quantities

Supported formula values: KineticEnergy, GravitationalPE, OhmsLaw, IdealGas, Momentum

display_style: "abbreviation" (default, e.g. 100 km) or "description" (e.g. 100 kilometers)

Catalog tools (10)

Tool	Params	Description
`uom_code__catalog_quantities`	`filter?`	List all 18 registrations (`"base"`, `"derived"`, or `"all"`)
`uom_code__catalog_units`	`registration`	All supported unit strings for a registration
`uom_code__catalog_unit_info`	`unit`	SI factor, dimension, and which registrations accept this unit
`uom_code__catalog_suggest_unit`	`registration, system?`	Recommend a unit (`"si"`, `"imperial"`, or `"any"`)
`uom_code__catalog_conversion_table`	`registration, si_value`	Table of all units for the SI value
`uom_code__catalog_formula_list`	—	All supported physics formulas with parameter descriptions
`uom_code__catalog_dimension`	`registration`	Dimensional analysis string (e.g. `L T⁻¹` for velocity)
`uom_code__catalog_compatible_units`	`registration, unit`	Units from the same measurement system
`uom_code__catalog_physics_constants`	—	Speed of light, G, h, kB, NA, e, g, ε0
`uom_code__catalog_base_quantities`	—	The 7 ISQ base quantities with SI units

Example workflow

1. uom_length__new(100.0, "kilometer")   → uuid-A
2. uom_time__new(2.0, "hour")            → uuid-B
3. uom_qty__div(uuid-A, uuid-B)          → uuid-C  (Velocity, 13.888... m/s)
4. uom_qty__convert(uuid-C, "kilometer_per_hour")  → 50.0
5. uom_velocity__emit([uuid-C])          → Rust code string
6. uom_code__emit_main([uuid-A, uuid-B, uuid-C])   → complete fn main()

Architecture

Multi-parameter factory (Phase 3F.6): register_quantity::<uom::si::f64::Length>("length") creates a typed HashMap<Uuid, Length>. No type erasure — uom_length__emit knows the exact (D, U, V) triple and generates perfect Length::new::<kilometer>(100.0) code.
QuantityBus: Arc<Mutex<HashMap<Uuid, QuantityBusEntry { registration, si_value }>>> shared between all registrations and UomCodePlugin. Enables cross-registration arithmetic (different typed HashMaps, same bus) and code emission from any plugin.
Dimension table (src/dimension.rs): pure function mapping (lhs_reg, op, rhs_reg) → result_reg. Arithmetic errors include dimensional context.
uom internals: all values stored in SI base units. Unit conversion via qty.get::<foot>() calls uom's internal conversion factors — no manual constants.

Cargo features

elicit_uom = { version = "...", features = ["emit"] }

The emit feature gates code-generation helpers in the elicitation primitives crate.

elicit_uom 0.11.1