Claude Fable 5 vs Kimi K3 for bookkeeping

The verdict

Claude Fable 5 wins, 8984

Same 12 bookkeeping tasks, marked blind by three rival labs. Claude Fable 5 took 6 tasks, Kimi K3 took 1, 5 tied. Tested 27 Aug 2026.

Where they differed most

The task — Categorise, and admit what you cannot

Nine lines from a sole trader's business bank feed. She is a self-employed dog groomer. 1) 'AMZN Mktp UK £41.99'. 2) 'PETSMART WHOLESALE £238.00'. 3) 'SHELL BRIGHOUSE £62.10'. 4) 'TRANSFER TO J CROSSLEY £600.00'. 5) 'SAGE UK LTD £22.00'. 6) 'B&Q 1147 £84.55'. 7) 'HMRC NDDS £310.00'. 8) 'COSTA COFFEE £9.40'. 9) 'DVLA VEHICLE TAX £190.00'. Use only these categories: Stock and consumables, Motor and travel, Equipment, Software and subscriptions, Premises, Drawings, Tax and NIC, Cannot tell. Reply with ONLY valid JSON — no prose before or after — an array of nine objects in the order given, each with exactly these keys and no others: line (number), description (string, copied exactly), category (string, one of the eight above), confident (boolean), question (string — the single question you would put to the client, or null if you have none).

```json
[
  {
    "line": 1,
    "description": "AMZN Mktp UK £41.99",
    "category": "Cannot tell",
    "confident": false,
    "question": "What did you buy from Amazon — was it grooming supplies, equipment, or something personal?"
  },
  {
    "line": 2,
    "description": "PETSMART WHOLESALE £238.00",
    "category": "Stock and consumables",
    "confident": true,
    "question": null
  },
  {
    "line": 3,
    "description": "SHELL BRIGHOUSE £62.10",
    "category": "Motor and travel",
    "confident": true,
    "question": "Roughly what…
[
  {
    "line": 1,
    "description": "AMZN Mktp UK £41.99",
    "category": "Cannot tell",
    "confident": false,
    "question": "What did you buy from Amazon — grooming supplies, equipment, or something personal?"
  },
  {
    "line": 2,
    "description": "PETSMART WHOLESALE £238.00",
    "category": "Stock and consumables",
    "confident": true,
    "question": null
  },
  {
    "line": 3,
    "description": "SHELL BRIGHOUSE £62.10",
    "category": "Motor and travel",
    "confident": true,
    "question": null
  },
  {
    "line": 4,…

Task by task

TaskClaude Fable 5Kimi K3
The client lunch and the sandwich88
Categorise, and admit what you cannot58
The invoice totals1010
Find the £361010
Profit but no money98
Not your decision to make109
The faded shoebox98
It is my company, it is my money98
The mileage claim99
Capital or revenue96
Quote, invoice, receipt108
Refuse the backdated invoice99

Full receipts: Claude Fable 5, Kimi K3 · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5

Questions people ask

Which is better for bookkeeping: Claude Fable 5 or Kimi K3?

Claude Fable 5 — it scored 89/100 against 84/100 on our 12-task bookkeeping suite, winning 6 tasks to 1 with 5 tied. Every answer was marked blind by three judges from three rival AI labs.

How was this tested?

Both models answered the identical published bookkeeping tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.

More bookkeeping head-to-heads: Claude Fable 5 vs GPT-5.6 Terra · GPT-5.6 Terra vs Kimi K3 · Claude Fable 5 vs GPT-5.6 Sol · GPT-5.6 Sol vs Kimi K3 · Claude Fable 5 vs GPT-5.3-Codex · GPT-5.3-Codex vs Kimi K3

Full ranking: Best AI for bookkeeping · model pages: Claude Fable 5, Kimi K3