CODATA Fundamental Physical Constants (NIST)

codata/fundamental-constants

Returns the complete CODATA table of fundamental physical constants from NIST (2022 adjustment, 355 constants): speed of light, Planck constant, elementary charge, electron and proton masses, Boltzmann constant, Avogadro constant, and derived quantities such as Bohr radius and conversion factors. Each row has the quantity name, the value, its standard uncertainty, and the unit. Values and uncertainties are strings exactly as NIST prints them, with digit grouping spaces and a trailing ellipsis where an exact value is truncated; an exponent is written like e-11. Defined constants carry exact true and a null uncertainty; a dimensionless quantity has a null unit. Takes no input and always returns the whole table, about 45 KB. Data from NIST CODATA. Served by Eden Engine; not an official NIST product.

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Price

$0.0026 per call

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Data source

NIST CODATA

Data from the NIST Reference on Constants, Units, and Uncertainty (CODATA recommended values, physics.nist.gov/constants). NIST asks for an appropriate byline. Served by Eden Engine; not an official NIST product.

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agent

// 1. search: find the tool
omnial_search({ query: "what you need" })

// 2. inspect: price and input schema
omnial_inspect({ tool: "codata/fundamental-constants" })

// 3. learn: read the usage guide at runtime
omnial_learn({ tool: "codata/fundamental-constants" })

// 4. run: price the exact call first, then run it
omnial_execute({ tool: "codata/fundamental-constants", input: { /* see input_schema */ }, dry_run: true })
omnial_execute({ tool: "codata/fundamental-constants", input: { /* ... */ } })

// 5. settle: the call is charged when it finishes, nothing to do

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Pricing

Every charge this tool can incur.

Charge	Price
Per call	$0.0026

Updated: Oct 25, 2026

Input and output schemas

Input schema

input_schema.json

{
  "type": "object",
  "properties": {},
  "additionalProperties": false
}

Output schema

output_schema.json

{
  "type": "object",
  "required": [
    "constants",
    "count"
  ],
  "properties": {
    "count": {
      "type": "integer",
      "description": "Number of rows in `constants`."
    },
    "constants": {
      "type": "array",
      "items": {
        "type": "object",
        "required": [
          "name",
          "value",
          "uncertainty",
          "unit",
          "exact"
        ],
        "properties": {
          "name": {
            "type": "string",
            "description": "Quantity name, for example 'Planck constant'."
          },
          "unit": {
            "type": [
              "string",
              "null"
            ],
            "description": "SI unit as printed, for example 'J Hz^-1'. null for a dimensionless quantity."
          },
          "exact": {
            "type": "boolean",
            "description": "true when NIST marks the value (exact), that is, defined with no uncertainty."
          },
          "value": {
            "type": "string",
            "description": "Value as printed by NIST: digit groups separated by spaces, an exponent written like e-11, and a trailing '...' when an exact value is truncated."
          },
          "uncertainty": {
            "type": [
              "string",
              "null"
            ],
            "description": "Standard uncertainty in the same format and unit as the value. null for an exact (defined) constant."
          }
        },
        "additionalProperties": false
      },
      "description": "Every constant in the published table, in NIST's order."
    }
  },
  "additionalProperties": false
}