Skip to content

Suite architecture

How mcp-ltspice-qucs fits inside eng-mcp-suite.

The internal architecture of the three servers (interop contract, Envelope shape, Touchstone exchange format) is documented in ARCHITECTURE.md. This page is about the external boundary: what this MCP feeds, what it consumes, and which workflow bundles include it.

Position in eng-mcp-suite

mcp-ltspice-qucs sits in the circuit-level synthesis + simulation layer of the engineering MCP stack. It deliberately stops at the antenna port and at the schematic-to-layout boundary.

        ┌───────────────────────────────────────────────┐
        │   MCP client (Codex, Claude, IDE, etc.)       │
        └──────┬──────────────┬───────────────┬─────────┘
               │              │ via MCP       │
       ┌───────▼──────────┐  ┌▼──────────┐  ┌─▼─────────────────┐
       │ mcp-ltspice-qucs │  │ lineforge │  │ mcp-nec2-antenna  │
       │  (circuits +     │  │  (T-line) │  │  (wire / MoM)     │
       │   filters)       │  └───────────┘  └───────────────────┘
       └───────┬──────────┘
               │  Touchstone .s2p / .snp
       ┌───────▼──────────────────────────┐
       │  mcp-pcb-emcopilot               │  (layout-aware EMC / SI)
       │  mcp-emc-regulations             │  (limit / spec lookup)
       └──────────────────────────────────┘

Feeds (this MCP produces output that)…

  • mcp-pcb-emcopilot: candidate filter schematic + Touchstone .s2p for layout-aware insertion-loss budgeting and review.
  • mcp-emc-regulations: predicted conducted-emission spectrum from SMPS designs for margin-check against CISPR 22 / CISPR 32.
  • mcp-rf-analysis (internal): Touchstone output from mcp-ltspice is consumable by cascade / de-embed tools through the shared file contract.

Consumes (this MCP accepts input from)…

  • lineforge: characteristic impedance + εr_eff for matching network design on a known PCB cross-section.
  • mcp-nec2-antenna: antenna feedpoint impedance for matching- network synthesis.

Workflow bundles that include this MCP

Bundle Role of this MCP
rf-design Filter + matching network synthesis
coexistence-review Multi-radio band picking + co-existence filter design
smps-emc SMPS topology sizing + conducted-emission prediction

See the suite manifest for full bundle definitions.

Design decisions

  • Three servers, one workspace. mcp-ltspice, mcp-qucs-s, and mcp-rf-analysis share rf-mcp-common for the Envelope[T] response model, versioned CircuitDocument, backend/result contracts, optimization contracts, and Touchstone I/O. This lets an agent compose cross-server calls without reconstructing topology.
  • Circuit IR before backend syntax. Supported LTspice ASC, SPICE, Qucs schematic, and Qucsator netlist inputs become an explicit pin-to-net graph. Unsupported constructs are blocking diagnostics, never guessed topology.
  • Model-aware optimization. Component selection attaches immutable model identities to the IR. Final simulator validation and yield runs must attest the exact selected hashes before the result can be labelled validated.
  • Touchstone as the simulation exchange format. Tools that exchange frequency-domain network data use Hz-strict Touchstone. Synthesis, catalog, EMC, and device-query tools return structured envelopes instead.
  • External simulators, not embedded. LTspice/ngspice, qucsator-RF, and Xyce are invoked as subprocesses. This keeps licensing boundaries clear and lets users point at existing installations.