Mathlas ships a free, no-LLM math MCP server with Lean 4 and PSLQ verification
u/KrishiAttri123 released mathlas, a free MCP server that gives AI coding clients 13 deterministic math tools — including OEIS lookup, Lean 4 typechecking, and PSLQ conjecturing — without ever calling an LLM or requiring an API key.
Score breakdown
Mathlas replaces LLM-based math tools — which hallucinate and require API keys — with a deterministic, zero-cost MCP server that plugs directly into existing AI coding clients for verifiable math reasoning via Lean 4 and PSLQ.
- 01Mathlas is a free MCP server that never calls an LLM and requires no API key.
- 02It provides 13 tools, including search over a 1.635M-document math index, OEIS sequence lookup, closed-form constant ID, Lean 4 kernel typechecking, and PSLQ conjecturing.
- 03The author claims a false-positive rate of 0 across all verification tiers.
Mathlas is an MCP server authored by u/KrishiAttri123 and released under the PolyForm-NC 1.0.0 (noncommercial) license. Its core design principle is that the AI client acts as the reasoning layer while mathlas acts as the deterministic "hands," returning structured data rather than generated text. It requires no API key, calls no LLM internally, and installs via `pip install mathlas-mcp` with a single `claude mcp add` command.
The author states the false-positive rate is 0 across every verification tier.
The server provides 13 tools, including search over a 1.635M-document math index, exact OEIS sequence ID lookup, closed-form constant identification, a real Lean 4 kernel typecheck, and Ramanujan-Machine (PSLQ) conjecturing. The author states the false-positive rate is 0 across every verification tier.
The post also describes a self-augmenting web loop evaluated on TheoremSearch's 110-query benchmark. Running corpus-only, mathlas hits a hard coverage floor of 10% theorem Hit@20 because TheoremSearch withheld 85% of their corpus. When the AI web-finds missing statements and fuses them into the dense channel via `add_finding()`, coverage repairs to 59% theorem / 70% paper Hit@20 — past TheoremSearch (45/56.8), Gemini 3 Pro (27), ChatGPT 5.2 (19.8), and Google (37.8 paper). The author explicitly notes this gain reflects the loop repairing withheld coverage rather than native retrieval superiority, and that on the reachable subset mathlas is merely on par.
Key facts
- 01Mathlas is a free MCP server that never calls an LLM and requires no API key.
- 02It provides 13 tools, including search over a 1.635M-document math index, OEIS sequence lookup, closed-form constant ID, Lean 4 kernel typechecking, and PSLQ conjecturing.
- 03The author claims a false-positive rate of 0 across all verification tiers.
- 04On TheoremSearch's 110-query benchmark, corpus-only mathlas hits 10% theorem Hit@20 due to 85% of TheoremSearch's corpus being withheld.
- 05A self-augmenting web loop using `add_finding()` repairs coverage to 59% theorem / 70% paper Hit@20.
- 06Benchmark comparisons: TheoremSearch (45/56.8), Gemini 3 Pro (27), ChatGPT 5.2 (19.8), Google (37.8 paper).
- 07Licensed under PolyForm-NC 1.0.0 (noncommercial); installable via `pip install mathlas-mcp`.
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