simantic demo ble-pair: zero-signup two-node BLE scenario (stock ESP-IDF, real air frames)

[ShahriarAhnaf]

HN's Launch HN instructions require it: "Make sure there's a way for HN readers to try out and poke around your product. Remove signup barriers, at least for launch day" and "If you're only collecting email signups or beta users, it's probably too early for your Launch HN."

Today the first run dead-ends. pip install simantic and simantic install both need no auth, but every model fetch requires credentials (src/simantic/_replx.py:73 -> auth.load() -> SimError("needs credentials to fetch the model")). src/simantic/fixtures.py states it outright: "models are not distributed with this package."

Approach — no backend work needed. Bundle a pre-rendered .repl and a prebuilt ESP-IDF .elf in the wheel, and have demo call Sim(repl_text, elf) directly, skipping model resolution entirely. No get-mcu-details, no token, no dependency on the supabase#52 gating decision. The Rust Sim(repl_text, elf) entry point takes no auth at all.

Target invocation (uvx = zero install, not just zero signup):

uvx simantic demo esp32c3

Acceptance:

• runs on a clean machine with no ~/.sim_id and no network account
• prints real UART output from real ESP-IDF firmware
• bundled repl is the boot/UART/timer C3 platform — no radio, per the RE boundary (see epic)
• demo documented in README as the first thing a reader does

Part of the Launch HN milestone.

[ShahriarAhnaf]

Scope change — the demo is the two-node BLE scenario, not a single-chip boot.

A single chip booting and printing UART is exactly what the comparable flops posted ("Show HN: M33mu - Cortex-M33 emulation with TrustZone, reverse stepping, and GDB", 2 pts, 0 comments). The differentiated artifact already exists in the tree: crates/rn-engine/examples/esp32c3_ble_two_node.rs — two ESP32-C3s running stock, unmodified ESP-IDF bleprph + blecent, pairing over a shared BleMedium, both registered into one Emulation so they interleave on one virtual timeline at a 10 us quantum.

No competitor ships this. Wokwi is single-node, browser-only, no radio; QEMU has no BLE medium; Renode has never broken 7 points on HN across ~10 submissions. It also answers the unprompted question from the 217-point Wokwi thread directly — we are not simulating a peripheral, we are simulating the other device and the air between them.

Target:

uvx simantic demo ble-pair

• both nodes UART interleaved to the terminal, pairing visibly completing
• mask ROM + both flash images bundled or fetched without an account (the example currently hardcodes absolute paths under /Users/anoof)
• runs in well under a minute on a laptop
• simantic demo with no argument lists available scenarios

Model gating no longer blocks this. Per core#420 the Rust engine ships with full model access, so the demo needs no free-tier carve-out.