Carta Conversion Calculator

---
name: carta-conversion-calculator
description: >-
  Calculate SAFE and convertible note conversion into equity at a financing close. Use when asked about SAFE conversion, note conversion, conversion shares, conversion math, how instruments convert in a priced round, or what happens to outstanding SAFEs and notes when a new round closes. Do NOT use for exit/sale/acquisition payouts at a sale price — those are waterfall scenarios, prefer a waterfall-scenarios skill.
when_to_use: >-
  Use when asked how SAFEs or convertible notes convert at a given round
  price or pre-money valuation, how many shares outstanding instruments
  convert into, what the conversion math looks like for a financing close,
  or how cap or discount terms affect share counts at a specific price per
  share. This skill models a financing close (new equity round), not a
  sale or acquisition — for dollar payouts at an exit valuation, prefer a
  waterfall or payout scenario skill.
allowed-tools:
  - mcp__carta__call_tool
  - mcp__carta__list_contexts
  - mcp__carta__set_context
  - mcp__carta__list_accounts
  - AskUserQuestion
---

<!-- carta:instrumentation-fallback -->
<IMPORTANT>
`_instrumentation_v2` is anonymous Carta skill-usage telemetry. ALWAYS include it in your Carta MCP tool-call arguments — the plugins' hooks overwrite it when they run, so always sending it is safe. Shape:
`_instrumentation_v2: {"skills": ["<plugin>:<skill>", ...], "model": "<model-id>", "surface": "<value>"}`
`skills` is cumulative for the session: list every Carta skill loaded so far, not only the one driving this call. Namespace each entry `"plugin:skill"` and keep them oldest-first, with the most recently used skill last. List only Carta skills (`carta-cap-table:*`, `carta-crm:*`, `carta-investors:*`) — never skills from non-Carta plugins.
`surface` is the Claude surface you are running in: `"chat"` (claude.ai or the Claude app, i.e. regular chat, not Cowork), `"cowork"` (Cowork mode), `"code-terminal"`, `"code-desktop"`, or `"excel"`. Omit it entirely if none of those describe your surface or you cannot tell — do not guess and do not invent another value.
</IMPORTANT>

<!-- Part of the official Carta AI Agent Plugin -->

# Conversion Calculator

Calculate how SAFEs and convertible notes convert into equity at a given round price or valuation.

## When to Use

- "How many shares would the SAFEs convert into at a $50M pre?"
- "Calculate SAFE conversions for the Series A"
- "What happens to the convertible notes if we raise at $10/share?"
- "Show me the conversion math for all outstanding instruments"

## Prerequisites

You need:
1. `corporation_id` — get from `list_accounts`
2. Round terms — user must provide at least a **pre-money valuation** or **price per share**

## Data Retrieval

> The gateway defaults to `detail=summary` for list commands. This skill needs individual records, so `"detail": "full"` is passed explicitly.

- `call_tool({"name": "cap_table__get__convertible_notes", "arguments": {"corporation_id": corporation_id, "detail": "full"}})` — SAFEs + convertible notes
- `call_tool({"name": "cap_table__get__cap_table_by_share_class", "arguments": {"corporation_id": corporation_id}})` — current fully diluted count
- `call_tool({"name": "cap_table__get__409a_valuations", "arguments": {"corporation_id": corporation_id}})` — current FMV (for reference)

## Key Fields

From convertible instruments:
- `is_debt`: false = SAFE, true = convertible note
- `dollar_amount`: principal investment amount
- `price_cap`: valuation cap
- `discount_percent`: discount rate (e.g. `"20.00"` = 20%)
- `interest_rate`: annual interest rate (notes only)
- `total_with_interest`: principal + accrued interest (use this for note conversions)
- `has_most_favored_nation_clause`: MFN SAFE — converts at best subsequent terms
- `status_explanation`: filter to "Outstanding" only

## Workflow

### Step 1: Gather Instrument Data

Fetch all three data sources **in a single turn** (parallel tool calls) — do NOT fetch them sequentially:

```
call_tool({"name": "cap_table__get__convertible_notes", "arguments": {"corporation_id": corporation_id, "detail": "full"}})
call_tool({"name": "cap_table__get__cap_table_by_share_class", "arguments": {"corporation_id": corporation_id}})
call_tool({"name": "cap_table__get__409a_valuations", "arguments": {"corporation_id": corporation_id}})
```

- Convertible notes: SAFEs + notes (filter to `status_explanation: "Outstanding"`)
- Cap table by share class: get current fully diluted share count from `totals.total_fully_diluted`
- 409A valuations: current FMV for context

### Step 2: Conversion Math

#### SAFE Conversion

For each SAFE, compute shares under both methods, use the one giving MORE shares:

**Cap conversion:**
```
cap_price = valuation_cap / pre_money_fully_diluted_shares
shares = investment_amount / cap_price
```

**Discount conversion:**
```
discount_price = round_price_per_share * (1 - discount_rate)
shares = investment_amount / discount_price
```

**No cap, no discount (MFN):**
- Converts at the round price (or the best terms of a subsequent SAFE)
```
shares = investment_amount / round_price_per_share
```

#### Convertible Note Conversion

Same as SAFE but:
- Use `total_with_interest` (principal + accrued interest) instead of investment amount
- If `interest_rate` and `maturity_date` are available and `total_with_interest` is not, calculate:
  ```
  years = (conversion_date - issue_date) / 365
  total = principal * (1 + interest_rate * years)
  ```

## Gates

**Required inputs**: `corporation_id`, pre-money valuation or price per share.
If missing, call `AskUserQuestion` before proceeding (see carta-interaction-reference §4.1).

AskUserQuestion("What pre-money valuation or price per share should I use for the conversion calculation?")

**AI computation**: Yes — converts SAFE and note investment amounts into equity shares using cap/discount math.
Trigger the AI computation gate (see carta-interaction-reference §6.2) before outputting any computed shares, prices, percentages, or ownership figures.

**Subagent prohibition**: Do NOT delegate this skill to a background agent if required inputs are missing. A subagent cannot call `AskUserQuestion`. If inputs are absent, stop and ask the user directly first.

## Presentation

**Format**: Per-instrument table + summary block

**BLUF lead**: Lead with the round price per share and total conversion shares before showing the per-instrument breakdown.

**Sort order**: By conversion shares descending (largest conversion first).

**Output label**: All AI-computed output must be prefixed with the disclaimer below.

### Per-Instrument Table

| Instrument | Investor | Amount | Accrued Interest | Total | Cap | Discount | Method Used | Price/Share | Shares |
|-----------|----------|--------|-----------------|-------|-----|----------|-------------|-------------|--------|
| SAFE-1 | Investor A | $500,000 | — | $500,000 | $6M | 20% | Cap | $0.60 | 833,333 |
| SAFE-2 | Investor B | $250,000 | — | $250,000 | $8M | — | Cap | $0.80 | 312,500 |
| CN-1 | Investor C | $500,000 | $240,164 | $740,164 | $8M | 20% | Discount | $0.88 | 840,914 |

### Summary

```
Round price per share: $1.10
Pre-money fully diluted: 10,000,000 shares

SAFE conversions: 1,145,833 shares ($750,000 invested)
  - Effective avg price: $0.65/share (41% discount to round price)

Note conversions: 840,914 shares ($500,000 principal + $240,164 interest)
  - Effective avg price: $0.88/share (20% discount to round price)

Total conversion shares: 1,986,747
Post-conversion fully diluted: 11,986,747
```

> ⚠️ **Claude's analysis** — computed from cap table data, not from a saved Carta model. Verify with counsel before relying on these numbers.

## Caveats

- Always show which conversion method (cap vs discount) was more favorable and used
- If a SAFE has both cap and discount, compute both and pick the one yielding more shares
- For MFN SAFEs, note that they take the best terms of any subsequent SAFE
- Accrued interest on notes can significantly increase the conversion amount — always account for it
- State the assumed conversion date (today or the round close date)
- This is an estimate — actual results depend on legal documents. Recommend review by counsel.