> For the complete documentation index, see [llms.txt](https://docs.fira.money/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fira.money/developers/protocol-contracts/core/fira-market.md). # FiraMarket {% hint style="info" %} **Source:** `src/fira_bonding/core/Market/v3/FiraMarket.sol` {% endhint %} ## Contract summary `FiraMarket` extends `FiraERC20` — the LP token *is* the market contract itself. It holds BT and FW reserves and tracks internal balances separately from actual token balances to prevent interference from direct transfers. Key state is packed into `MarketStorage` for gas: `totalBt`, `totalFw` (int128), `lastLnImpliedRate` (uint96), and oracle observation indices (uint16 each). ## Functionality ### Mint (add liquidity) `mint(receiver, netFwDesired, netBtDesired)` loads state into memory, calls `MarketMathCore.addLiquidity`, and writes back. On first deposit it locks `MINIMUM_LIQUIDITY` (1000 wei of LP) to `address(1)` to prevent the first-depositor rounding attack. Subsequent deposits mint LP proportional to the limiting token. Tokens must be transferred to the market before calling `mint` — the contract does not pull. ### Burn (remove liquidity) `burn(receiverFw, receiverBt, netLpToBurn)` burns LP from `address(this)`, computes proportional FW and BT outputs, and transfers them out. LP must be sent to the market before calling. Works both pre- and post-expiry. ### Swaps * **`swapExactBtForFw`** — Flash-callback pattern: sends FW out first, then verifies BT repayment via callback. * **`swapFwForExactBt`** — Sends BT out first, calls back, checks FW repayment. Both swap functions send the reserve fee portion to the treasury and are gated by `notExpired`. ### Oracle Every call to `_writeState` writes a new observation to the `OracleLib` ring buffer. `observe(secondsAgos)` returns cumulative `ln(impliedRate)` values for TWAP calculations. `increaseObservationsCardinalityNext` lets anyone pre-allocate observation slots. ### Skim `skim()` sends any excess BT or FW (above internal totals) to the treasury. This prevents direct transfers from affecting pool pricing. ## Invariants * Internal `totalBt` and `totalFw` are never affected by direct transfers * Exchange rate is always >= 1.0 (BT trades at a discount to FW) * `address(0)` and `address(this)` never have reward or balance accounting * Swaps and mints revert after expiry; burns work at any time --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.fira.money/developers/protocol-contracts/core/fira-market.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.