{
  "capability_id": "chemistry.acid_base.henderson_hasselbalch",
  "tool_id": "henderson-hasselbalch",
  "engine": "henderson-hasselbalch",
  "calculation_version": "1.0.1",
  "generated_at": "2026-10-23T01:27:11.351Z",
  "engine_build": "2026-09-25",
  "test_count": 11,
  "passed": 11,
  "failed": 0,
  "tests_summary": {
    "golden": {
      "passed": 1,
      "total": 1
    },
    "boundary": {
      "passed": 5,
      "total": 5
    },
    "property": {
      "passed": 5,
      "total": 5
    }
  },
  "engine_tested": true,
  "expert_reviewed": false,
  "internally_reviewed": false,
  "review_kind": null,
  "source_checked": true,
  "reviewed_by": null,
  "reviewer_role": null,
  "last_reviewed": null,
  "expert_review": {
    "status": "optional_not_performed",
    "reviewer": null,
    "scope": [
      "formula",
      "input semantics",
      "assumptions",
      "limitations",
      "sources",
      "tests"
    ],
    "note": "Domain expert review is optional under CVP (CVP-EXP-01). Absence does not block CVP Verified. See Review policy for supplemental domain assurance."
  },
  "internal_review": {
    "status": "not_applicable",
    "reviewer": null
  },
  "page": "https://www.calculatorx.com/calc/chemistry/henderson-hasselbalch",
  "api": "https://www.calculatorx.com/api/v1/calc/henderson-hasselbalch",
  "schema_input": "https://www.calculatorx.com/schemas/chemistry.acid_base.henderson_hasselbalch.input.json",
  "schema_output": "https://www.calculatorx.com/schemas/chemistry.acid_base.henderson_hasselbalch.output.json",
  "assumptions": [
    "Monoprotic buffer; HA and A− are the pair as given",
    "Activity coefficients ≈ 1",
    "Not ICE equilibrium",
    "Not pH = −log10[H+]",
    "Not polyprotic"
  ],
  "limitations": [
    "Monoprotic buffer pair as given — not ICE equilibrium",
    "Not pH = −log10[H+]",
    "Not activity coefficients or polyprotic"
  ],
  "boundary_conditions": [
    "missing pKa and missing Ka → MISSING_REQUIRED_INPUT",
    "pKa and Ka together → MIXED_INPUT_ENCODING",
    "HA ≤ 0 or A ≤ 0 → VALUE_MUST_BE_POSITIVE",
    "Ka ≤ 0 → VALUE_MUST_BE_POSITIVE"
  ],
  "sources": [
    {
      "title": "OpenStax Chemistry 2e — Acid-Base Buffers",
      "section": "Henderson–Hasselbalch equation",
      "url": "https://openstax.org/books/chemistry-2e/pages/14-6-buffers",
      "supports": "pH = pKa + log10([base]/[acid]) for a conjugate pair",
      "kind": "reference"
    },
    {
      "title": "IUPAC Gold Book — buffer solution",
      "section": "conjugate acid–base pair",
      "url": "https://goldbook.iupac.org/terms/view/B00753",
      "supports": "A buffer is a conjugate acid–base pair whose ratio sets pH",
      "kind": "standard"
    }
  ],
  "methods": [],
  "fingerprint": "sha256:247d67238603e25e60952acb7369fae6eb21d102d14e49cea9113f1aa3cdea16",
  "tier": "engine_tested",
  "verification": {
    "tests": {
      "passed": 11,
      "total": 11,
      "golden": 1,
      "boundary": 5,
      "property": 5
    },
    "contract_checks": {
      "passed": 6,
      "total": 6
    }
  },
  "evidence_core_generated_at": "2026-09-25T00:17:40.683Z",
  "rendered_at": "2026-10-23T01:27:11.351Z",
  "release_integrity": {
    "status": "verified",
    "scope": "workspace",
    "production_attestation_required": true,
    "calculation_version": "1.0.1",
    "artifacts": {
      "engine": "1.0.1",
      "page": "1.0.1",
      "capability": "1.0.1",
      "evidence": "1.0.1",
      "input_schema": "1.0.1",
      "output_schema": "1.0.1",
      "mcp_contract": "1.0.1"
    },
    "digests": {
      "input_schema_sha256": "ce20f2f51db961b2a4bd21752670c34893549d02faec96c6656120eeb6fd182d",
      "output_schema_sha256": "d189af345059376b65ecb82ca089cbab82a24806606b6254ab32d8c14641a0d4",
      "evidence_sha256": "05962c6ca50a818688c7f76ff78bdd13ee4af81c4aa7f2714b1ba254e9bba35b",
      "evidence_core_sha256": "05962c6ca50a818688c7f76ff78bdd13ee4af81c4aa7f2714b1ba254e9bba35b",
      "capability_sha256": "49e287985501c7728d209e6efa7f69e6334058d611c52cb636bd3c0e0dacd474",
      "engine_sha256": "a664ae25cd2134de7de43a99352933043215473589aec38c9416508150cb1008",
      "mcp_contract_sha256": "8defa770ea0b34118e3444b698842353896edfffa88b4ef1c34898f3f5378790"
    },
    "contract_checks": {
      "total": 6,
      "passed": 6,
      "failed": 0,
      "items": [
        {
          "id": "release-artifacts-aligned",
          "status": "pass",
          "detail": "1.0.1"
        },
        {
          "id": "schema-output-required-declared",
          "status": "pass"
        },
        {
          "id": "schema-valid-input-executes",
          "status": "pass"
        },
        {
          "id": "engine-success-output-validates-schema",
          "status": "pass"
        },
        {
          "id": "schema-rejects-incomplete-input",
          "status": "pass"
        },
        {
          "id": "rest-success-payload-validates-schema",
          "status": "pass"
        }
      ]
    },
    "report": "https://www.calculatorx.com/.well-known/calculatorx-release-integrity.json"
  },
  "tests": [],
  "disclosure": {
    "policy": "calculatorx-public-evidence-v1",
    "full_validation": "private",
    "representation": "summary"
  }
}