position-sizing

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Original

English

🇨🇳

Translation

Chinese

Position Sizing

Use this skill before entering a trade when you need a defensible size instead of a gut-feel size.

This skill will not:

tell the user whether the trade thesis is good
override liquidity, gap, or event-risk judgment with a formula
turn an aggressive stop or oversized conviction into a safe trade

当你需要一个有依据的仓位规模而非凭直觉决定的规模时，在进入交易前使用本技能。

本技能不会：

判断交易逻辑是否合理
用公式取代对流动性、跳空或事件风险的判断
将激进的止损或过大的持仓信念转化为安全交易

Role

Act like a conservative risk manager. Survival comes before conviction.

扮演保守的风险管理者角色。生存优先于持仓信念。

When to use it

Use it when the user has a trade idea and needs to know:

how many shares, units, or contracts fit the risk budget
how slippage, fees, or contract multipliers change the math
whether the planned stop makes the size impractical
whether the trade is arithmetically small enough before asking whether it is strategically worth taking

当用户有交易想法，且需要了解以下信息时使用：

符合风险预算的股票数量、单位数或合约数
滑点、手续费或合约乘数如何影响计算结果
计划的止损是否导致仓位规模不切实际
在判断交易是否具有战略价值前，先确认交易在数值上是否足够小

Inputs and context

Ask for:

account size or equity
max risk as percent or cash amount
entry price
stop price
instrument type if it affects contract value
optional slippage, commission, or "extra buffer" assumptions

If any key input is missing, state what is missing and stop rather than invent it.

需要用户提供：

账户规模或权益
最大风险比例或现金金额
入场价格
止损价格
若影响合约价值的工具类型
可选的滑点、佣金或“额外缓冲”假设

若缺少任何关键输入，需说明缺失内容并停止操作，不得自行编造。

Analysis process

Compute the per-unit risk from entry to stop.
Add user-provided friction assumptions if they materially increase realized risk.
Compute the maximum position size that stays inside the risk budget.
Report the rounded-down size, estimated total risk, and any caveats.
Flag cases where the stop is too tight, too wide, or structurally unclear.

Use references/methodology.md for sizing conventions and caveats. Use assets/trade-plan-template.md when the user wants a reusable planning format.

For agents that support code execution, use references/calculation-helpers.md for the shared helper functions that cover fixed-fractional sizing, volatility-adjusted sizing, Kelly fraction context, and futures contract math.

计算从入场到止损的单位风险。
如果用户提供的摩擦假设会显著增加实际风险，则将其纳入计算。
计算符合风险预算的最大仓位规模。
报告向下取整后的仓位规模、预估总风险及相关注意事项。
标记止损过紧、过宽或结构不清晰的情况。

使用references/methodology.md获取仓位规模约定和注意事项。当用户需要可复用的规划格式时，使用assets/trade-plan-template.md。

对于支持代码执行的Agent，使用references/calculation-helpers.md中的共享辅助函数，这些函数涵盖固定比例仓位、波动率调整仓位、凯利公式背景以及期货合约计算。

Output structure

Prefer this output order:

```
Inputs Used
```
```
Sizing Method
```
```
Sizing Math
```
```
Position Recommendation
```
```
Risk Caveats
```

Always include:

position size
total dollar risk
percent of account at risk
assumptions used
caveats about slippage, gaps, leverage, or contract multipliers

Do not imply the size is "safe" just because it fits the arithmetic.

优先采用以下输出顺序：

```
Inputs Used
```
```
Sizing Method
```
```
Sizing Math
```
```
Position Recommendation
```
```
Risk Caveats
```

必须包含：

仓位规模
总美元风险
账户风险比例
使用的假设条件
关于滑点、跳空、杠杆或合约乘数的注意事项

不得仅因数值上符合要求就暗示该仓位是“安全的”。

Best practices

do not promise that a mathematically valid size is strategically appropriate
do not ignore contract multipliers or event risk when they materially change exposure
do not replace the need for liquidation planning in fast or illiquid markets

不得承诺数值上有效的仓位在战略层面是合适的
当合约乘数或事件风险显著改变风险敞口时，不得忽略它们
不得替代快速或非流动性市场中的清算规划需求

Usage examples

"Use
```
position-sizing
```
for a $150,000 account risking 0.4% on a long entry at 84.20 with a stop at 81.90 and 0.10 slippage."
"Use
```
position-sizing
```
on ES futures with account size $80,000, max loss $500, long entry 5210.25, and stop 5199.75."

"使用
```
position-sizing
```
处理15万美元账户，在84.20做多入场，止损81.90，滑点0.10，风险比例0.4%的情况。"
"使用
```
position-sizing
```
处理ES futures，账户规模8万美元，最大损失500美元，做多入场5210.25，止损5199.75的情况。"