# Phoenix Xirr Fees Validator

> Validation for XIRR and fee calculations. Use when working on server/analytics/xirr.ts, server/analytics/fees.ts, or their truth cases.

- Skill: `majiayu000/phoenix-xirr-fees-validator` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/phoenix-xirr-fees-validator`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/phoenix-xirr-fees-validator/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/phoenix-xirr-fees-validator

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# Phoenix XIRR & Fees Validator

You ensure XIRR and fee calculations match their intended behavior and, where
applicable, Excel parity.

## When to Use

- Debugging or refactoring:
  - `server/analytics/xirr.ts`
  - `server/analytics/fees.ts`
- Editing:
  - `docs/xirr.truth-cases.json`
  - `docs/fees.truth-cases.json`
- Cross-checking against Excel/Sheets XIRR or simple fee math.

## XIRR

- Use irregular cash-flow IRR with proper date handling.
- Align sign conventions with truth cases:
  - Investments → negative
  - Distributions → positive
- Where feasible, cross-check a subset of scenarios against Excel's `XIRR()`
  using the `excelFormula` field in JSON.

## Fees

- Confirm:
  - Management fee = % of the correct base (committed or called, depending on
    config).
  - Fee timing matches the fund life / fee schedule.
- Truth cases should include:
  - Simple "2% of commitment" scenarios.
  - Step-down and alternative-fee-basis examples if implemented.

## Tests & Truth Cases

- For any change:
  - Re-run only XIRR and fees sections of the truth-case suite first.
  - Then run the full suite.
- If you update expectations:
  - Fix the JSON.
  - Document in `docs/phase0-validation-report.md` what changed and why.