Source: https://guthlabs.ai/docs/instruments/derivative-calculator-symbolic-numeric/qualification/

instrument qualification / verified-with-binding-errata

# Derivative Calculator (symbolic + numeric) qualification

Verified with errata that must be applied at binding time.

Status: **VERIFIED_WITH_ERRATA**Lifecycle: **verified-with-binding-errata**

## Ledger verdict

Verified with errata that must be applied at binding time.

**Status**: VERIFIED_WITH_ERRATA

**Tranche**: tranche-8

**Review vectors**: 4

**Ledger rows**: 1

## Applied errata

````
[
  {
    "vector": 1,
    "field": "spot_checks[0] (at x=0)",
    "wrong": "input_side=-0.9999999999",
    "correct": "-1.9999999999 (matches answer_side=-2.0 to 10 decimals)",
    "cause": "the numeric finite-difference at x=0 is off by almost exactly a factor of 2 from the correct derivative — consistent with dividing by h instead of 2h in the central-difference formula; the SAME vector's x=1 spot-check is computed correctly, so the error is local to this one point, not the whole method"
  }
]
````

## Adversarial re-test context

The full catalog was re-tested from boundary, convention, and self-check angles in 2,787 requests. Five genuine computational defects were independently verified and corrected. This page reports the current ledger state for this instrument; it does not imply product deployment or interface qualification.

## Release gate

Bind every attached correction, replay the affected vectors, enforce boundary validation, and preserve evidence before describing the executable surface as qualified.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/derivative-calculator-symbolic-numeric/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/derivative-calculator-symbolic-numeric/mechanism/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/derivative-calculator-symbolic-numeric/implementation/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `STRESS_TEST_RECEIPT.json`

- `tranche errata record`