The open-source engine under the statements.
The counterparty statements run on the same code anyone can read: a Rust recalculation engine with 400+ Excel-compatible functions, and an agent toolkit that speaks native spreadsheet. No black box, no LibreOffice shell-out.
Two projects, one permissive stack.
An Arrow-backed, incremental recalculation engine. Topological scheduling, cycle detection, volatile handling, 400+ Excel-compatible functions — embeddable in Rust, Python, or WASM.
An MCP server and CLI (asp) that give an LLM agent native spreadsheet tools: discover regions, recalculate, trace dependencies, and fork / edit / diff / verify — with the formualizer engine built in.
Agents deserve better than openpyxl.
Most agent spreadsheet tooling reads cell values and hopes. It can’t recalculate, so it either ignores formulas or shells out to a headless LibreOffice and prays the numbers match. spreadsheet-mcp gives your agent the real engine.
Native recalc
The agent changes an input and the full dependency graph recomputes in-process — no LibreOffice, no subprocess, deterministic every time.
Dependency trace
Any cell resolves to the formula and the source cells that produced it, so the agent reasons about the math instead of guessing at values.
Fork · edit · diff
Branch a workbook, make edits, and get a precise cell-level diff of what moved — the substrate for safe, reviewable agent changes.
Verified edits
Edits are validated against the engine, not applied blind. What the agent writes is what recalculates — no drift between tool and truth.
The infrastructure is free. The statements are how we fund it.
A recalculation engine and an agent toolkit are the kind of infrastructure that should be permissively licensed and inspectable — so we license them MIT / Apache-2.0 and build in the open. Anyone can embed the engine, audit it, or ship on top of it.
The hosted product — live counterparty statements that trace to your cells — is how we fund that work. Open core, honest split: the commons stays open, and paying customers keep it maintained.