fix(pancakeswap-v2): v0.2.0 — fix remove-liquidity dry-run lpBalance and expectedToken overflow

submissions/pancakeswap-v2/LICENSE

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+MIT License
+
+Copyright (c) 2026 skylavis-sky
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

submissions/pancakeswap-v2/plugin.yaml

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+schema_version: 1
+name: pancakeswap-v2
+version: "0.2.0"
+description: "Swap tokens and provide full-range liquidity on PancakeSwap V2 — the xyk AMM on BSC and Base"
+author:
+  name: skylavis-sky
+  github: skylavis-sky
+category: defi-protocol
+tags:
+  - dex
+  - swap
+  - liquidity
+  - amm
+  - pancakeswap
+  - bsc
+  - v2
+  - xyk
+  - lp
+license: MIT
+
+components:
+  skill:
+    dir: skills/pancakeswap-v2
+
+build:
+  lang: rust
+  binary_name: pancakeswap-v2
+  source_repo: skylavis-sky/onchainos-plugins
+  source_commit: "83b306e1e3ccf4b14fc11a76bd5b906297340ef4"
+  source_dir: pancakeswap-v2
+
+api_calls:
+  - "https://bsc-rpc.publicnode.com"
+  - "https://base-rpc.publicnode.com"
+  - "https://api.pancakeswap.info/api/v2/tokens"

submissions/pancakeswap-v2/skills/pancakeswap-v2/SKILL.md

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+---
+name: pancakeswap-v2
+description: "Swap tokens and provide full-range liquidity on PancakeSwap V2 — the xyk AMM on BSC and Base. Trigger phrases: swap on pancakeswap v2, pancake swap, pcs v2 swap, add liquidity pancakeswap, remove liquidity pancake, pancake amm, pancakeswap v2 quote, check pancake pair. Chinese: 在PancakeSwap V2兑换代币, PancakeSwap添加流动性, PancakeSwap移除流动性, 查询Pancake报价"
+license: MIT
+metadata:
+  author: skylavis-sky
+  version: "0.2.0"
+---
+
+## Changelog
+
+### v0.2.0 (2026-04-11)
+
+**Bug fixes in `remove-liquidity`:**
+
+1. **`lpBalance` showed zero-address balance in dry-run** — When `--dry-run` was used without `--from`, the wallet was set to `0x0000…0000` for all reads, so `lpBalance` returned whatever LP tokens the zero address holds (typically the locked MINIMUM_LIQUIDITY) instead of the user's real balance. Fixed: dry-run now uses `--from` (if provided) or `onchainos::resolve_wallet` for reads; zero address is only the final fallback when no wallet is available.
+
+2. **`expectedTokenA / expectedTokenB` overflow for large pools** — The formula `reserve * lp_burned / total_supply` used raw `u128` multiplication. For high-liquidity pools (e.g. the BSC BNB/USDT pool with reserves > 10²² raw units), `reserve × lp_burned` overflows u128 (max ~3.4×10³⁸), producing garbage values. Fixed: `safe_mul_div` tries `checked_mul` first and falls back to `f64` arithmetic on overflow, matching the approach already used in `lp-balance`.
+
+Both bugs confirmed fixed via full live-transaction regression test suite (12 tests, BSC + Base, 2026-04-11).
+
+---
+
+## Architecture
+
+- Read ops (quote, get-pair, get-reserves, lp-balance) → direct `eth_call` via public RPC; no confirmation needed
+- Write ops (swap, add-liquidity, remove-liquidity) → after user confirmation, submits via `onchainos wallet contract-call --force`
+- ERC-20 approvals → manually encoded `approve()` calldata, submitted via `onchainos wallet contract-call --force`
+- Supports BSC (chain 56, default) and Base (chain 8453)
+- V2 uses constant-product xyk formula; LP tokens are standard ERC-20 (not NFTs); fixed 0.25% swap fee
+
+## Execution Flow for Write Operations
+
+1. Run with `--dry-run` first to preview calldata and estimated amounts
+2. **Ask user to confirm** the transaction details before proceeding
+3. Execute only after explicit user approval
+4. Report transaction hash and block explorer link
+
+---
+
+## Command Routing
+
+| User intent | Command |
+|-------------|---------|
+| "How much CAKE for 100 USDT?" | `pancakeswap-v2 quote` |
+| "Swap 100 USDT for CAKE on PancakeSwap V2" | `pancakeswap-v2 swap` |
+| "Add liquidity CAKE/BNB on PancakeSwap" | `pancakeswap-v2 add-liquidity` |
+| "Remove my CAKE/USDT liquidity on Pancake" | `pancakeswap-v2 remove-liquidity` |
+| "What is the CAKE/BNB pair address on PancakeSwap V2?" | `pancakeswap-v2 get-pair` |
+| "What are the reserves in the CAKE/BNB pool?" | `pancakeswap-v2 get-reserves` |
+| "How much LP do I have for CAKE/BNB?" | `pancakeswap-v2 lp-balance` |
+
+---
+
+## quote — Get Expected Swap Output
+
+**Trigger phrases:** quote pancakeswap, how much would I get, pancake v2 price, estimate swap
+
+**Usage:**
+```
+pancakeswap-v2 --chain 56 quote --token-in USDT --token-out CAKE --amount-in 100000000000000000000
+```
+
+**Parameters:**
+| Name | Flag | Description |
+|------|------|-------------|
+| tokenIn | `--token-in` | Input token: symbol (USDT, CAKE, WBNB) or hex address |
+| tokenOut | `--token-out` | Output token: symbol or hex address |
+| amountIn | `--amount-in` | Input amount in minimal units (e.g. 100e18 = 100 tokens for 18-decimal token) |
+| chain | `--chain` | Chain ID: 56 (BSC, default) or 8453 (Base) |
+
+**Example output:**
+```json
+{
+  "ok": true,
+  "data": {
+    "tokenIn": "0x55d398326f99059fF775485246999027B3197955",
+    "tokenOut": "0x0E09FaBB73Bd3Ade0a17ECC321fD13a19e81cE82",
+    "symbolIn": "USDT",
+    "symbolOut": "CAKE",
+    "amountIn": "100000000000000000000",
+    "amountOut": "23500000000000000000",
+    "amountOutHuman": "23.500000",
+    "path": ["0x55d3...", "0x0E09..."],
+    "fee": "0.25%",
+    "chain": 56
+  }
+}
+```
+
+Read-only operation — no confirmation required.
+
+---
+
+## swap — Swap Tokens
+
+**Trigger phrases:** swap on pancakeswap v2, pancake swap, exchange tokens on pcs, trade on pancakeswap
+
+**Usage:**
+```
+pancakeswap-v2 --chain 56 swap --token-in USDT --token-out CAKE --amount-in 100000000000000000000
+```
+
+**Parameters:**
+| Name | Flag | Description |
+|------|------|-------------|
+| tokenIn | `--token-in` | Input token: symbol or address. Use BNB/ETH for native |
+| tokenOut | `--token-out` | Output token: symbol or address |
+| amountIn | `--amount-in` | Input amount in minimal units |
+| slippageBps | `--slippage-bps` | Slippage in basis points (default 50 = 0.5%) |
+| deadlineSecs | `--deadline-secs` | Seconds until deadline (default 300) |
+| dryRun | `--dry-run` | Preview calldata only, no broadcast |
+
+**Execution flow:**
+1. Run `--dry-run` to preview the swap calldata and expected output
+2. **Ask user to confirm** the swap details (tokenIn, tokenOut, amountIn, amountOutMin, slippage)
+3. If tokenIn is an ERC-20 and allowance is insufficient, first submit an approve tx via `onchainos wallet contract-call --force`; **ask user to confirm** the approval
+4. Submit swap via `onchainos wallet contract-call --force`
+5. Report txHash and BscScan/BaseScan link
+
+**Supported swap variants:**
+- Token → Token (`swapExactTokensForTokens`)
+- BNB/ETH → Token (`swapExactETHForTokens`, pass `--token-in BNB`)
+- Token → BNB/ETH (`swapExactTokensForETH`, pass `--token-out BNB`)
+
+**Example output:**
+```json
+{
+  "ok": true,
+  "steps": [
+    {"step": "approve", "txHash": "0xabc..."},
+    {"step": "swapExactTokensForTokens", "txHash": "0xdef...", "explorer": "bscscan.com/tx/0xdef..."}
+  ]
+}
+```
+
+---
+
+## add-liquidity — Add Liquidity
+
+**Trigger phrases:** add liquidity on pancakeswap, provide liquidity pancake v2, become LP on pancakeswap, join pancake pool
+
+**Usage:**
+```
+# Token + Token
+pancakeswap-v2 --chain 56 add-liquidity --token-a CAKE --token-b USDT --amount-a 10000000000000000000 --amount-b 50000000000000000000
+
+# Token + native BNB
+pancakeswap-v2 --chain 56 add-liquidity --token-a CAKE --token-b BNB --amount-a 10000000000000000000 --amount-b 50000000000000000
+```
+
+**Parameters:**
+| Name | Flag | Description |
+|------|------|-------------|
+| tokenA | `--token-a` | First token: symbol or address. Use BNB/ETH for native |
+| tokenB | `--token-b` | Second token. Use BNB/ETH for native |
+| amountA | `--amount-a` | Desired amount of tokenA in minimal units |
+| amountB | `--amount-b` | Desired amount of tokenB (or native BNB/ETH) in minimal units |
+| slippageBps | `--slippage-bps` | Slippage tolerance (default 50 = 0.5%) |
+| dryRun | `--dry-run` | Preview calldata only |
+
+**Execution flow:**
+1. Check current pair reserves and ratio
+2. Run `--dry-run` to preview the transaction
+3. **Ask user to confirm** the amounts and LP token receipt before proceeding
+4. Approve Router02 to spend tokenA/tokenB via `onchainos wallet contract-call --force` (if needed); **ask user to confirm** each approval
+5. Submit `addLiquidity` or `addLiquidityETH` via `onchainos wallet contract-call --force`
+6. Report txHash and LP tokens received
+
+---
+
+## remove-liquidity — Remove Liquidity
+
+**Trigger phrases:** remove liquidity pancakeswap, withdraw liquidity from pancake, exit pancakeswap pool, burn LP tokens pancake
+
+**Usage:**
+```
+# Remove all LP
+pancakeswap-v2 --chain 56 remove-liquidity --token-a CAKE --token-b USDT
+
+# Remove specific amount
+pancakeswap-v2 --chain 56 remove-liquidity --token-a CAKE --token-b USDT --liquidity 1000000000000000000
+```
+
+**Parameters:**
+| Name | Flag | Description |
+|------|------|-------------|
+| tokenA | `--token-a` | First token |
+| tokenB | `--token-b` | Second token. Use BNB/ETH to receive native |
+| liquidity | `--liquidity` | LP tokens to burn (minimal units). Omit to remove all |
+| slippageBps | `--slippage-bps` | Slippage tolerance (default 50 = 0.5%) |
+| dryRun | `--dry-run` | Preview only |
+
+**Execution flow:**
+1. Fetch LP balance and compute expected token withdrawals
+2. Display summary: LP amount, expected tokenA and tokenB out
+3. Run `--dry-run` to preview calldata
+4. **Ask user to confirm** the removal details before proceeding
+5. Approve LP tokens to Router02 via `onchainos wallet contract-call --force`; **ask user to confirm**
+6. Submit `removeLiquidity` or `removeLiquidityETH` via `onchainos wallet contract-call --force`
+7. Report txHash
+
+---
+
+## get-pair — Look Up Pair Address
+
+**Trigger phrases:** find pancakeswap pair, what is the pancake pair address, does pancake v2 have a pool for
+
+**Usage:**
+```
+pancakeswap-v2 --chain 56 get-pair --token-a CAKE --token-b BNB
+```
+
+Read-only — no confirmation required.
+
+---
+
+## get-reserves — Get Pool Reserves
+
+**Trigger phrases:** pancakeswap pool reserves, pancake pool price, what is the price in pancake v2, check pancake liquidity
+
+**Usage:**
+```
+pancakeswap-v2 --chain 56 get-reserves --token-a CAKE --token-b BNB
+```
+
+Read-only — no confirmation required.
+
+---
+
+## lp-balance — Check LP Token Balance
+
+**Trigger phrases:** how much LP do I have in pancake, check my pancakeswap position, my pancake v2 liquidity
+
+**Usage:**
+```
+pancakeswap-v2 --chain 56 lp-balance --token-a CAKE --token-b BNB
+pancakeswap-v2 --chain 56 lp-balance --token-a CAKE --token-b BNB --wallet 0xYourAddress
+```
+
+Read-only — no confirmation required.
+
+---
+
+## Token Symbols (BSC)
+
+| Symbol | Address |
+|--------|---------|
+| WBNB / BNB | `0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c` |
+| CAKE | `0x0E09FaBB73Bd3Ade0a17ECC321fD13a19e81cE82` |
+| USDT | `0x55d398326f99059fF775485246999027B3197955` |
+| USDC | `0x8AC76a51cc950d9822D68b83fE1Ad97B32Cd580d` |
+| BUSD | `0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56` |
+
+For Base (8453): WETH `0x4200000000000000000000000000000000000006`, USDC `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`.
+
+---
+
+## Troubleshooting
+
+| Error | Likely cause | Fix |
+|-------|-------------|-----|
+| "No V2 liquidity path found" | No direct or WBNB-routed pair exists | Use a different token pair or check on BscScan |
+| "You have no LP tokens for this pair" | Wallet has 0 LP balance | Verify correct wallet address and chain |
+| txHash is "pending", never broadcasts | Missing `--force` flag | Plugin always adds `--force`; check onchainos version |
+| Swap reverts on-chain | Slippage too tight or stale price | Increase `--slippage-bps` (e.g. 100 for 1%) |
+| "Cannot resolve wallet address" | onchainos not logged in | Run `onchainos wallet login` or pass `--from <address>` |
+| "Unsupported chain ID" | Chain not 56 or 8453 | Use `--chain 56` (BSC) or `--chain 8453` (Base) |