peat-btle

name: peat-btle description: Per-repo skill for the Peat BLE mesh transport — multi-platform Rust crate (Linux/macOS/iOS/Android/ESP32) plus an Android AAR via UniFFI. when_to_use: Editing files under peat-btle/, reviewing peat-btle PRs, debugging BLE advertise/scan/GATT/peripheral issues, working on M5Stack/ESP32 firmware integration, or working on ADR slices that touch the BLE transport. verifies_with: cargo fmt --check, cargo clippy -- -D warnings, cargo test (host platform), plus per-platform feature builds for any flag whose paths the change touches.

`peat-btle` SKILL

peat-btle is the Bluetooth Low Energy transport for the Peat Protocol. It implements a Transport-shaped surface plus the wire codec primitives (typed BLE structs, *_to_* JSON projections, 0xB6 framing) that other peat-* code can plug into for BLE-based peer connectivity. peat-btle has zero peat-mesh dep as of 0.4.0 (ADR-059 Amendment 4 Slice 4.b deleted the back-edge); peat-mesh's bluetooth feature wraps these primitives with its own Translator trait impl in peat-mesh's tree. The crate is multi-platform: Linux uses bluer (BlueZ), macOS/iOS use objc2-core-bluetooth, Android uses UniFFI bindings consumed by the ATAK plugin, ESP32 uses NimBLE. The translator-codec feature is what consumers (peat-mesh-using hosts and standalone embedded callers like M5Stack Core2 / Bitchat-style sensors) enable to get the wire codec.

When this skill applies

Editing any file under src/ (transport, peer, platform, codec)
Editing android/ (Gradle/Kotlin AAR build)
Editing uniffi-bindgen/ or anything that affects generated bindings
Touching the feature-flag matrix in Cargo.toml
Working on M5Stack / ESP32 firmware that pins this crate
Working on an active slice of any local ADR (docs/adr/) or any ecosystem ADR that lands here. Recent ecosystem slices touching this repo: ADR-032 (pluggable transport), ADR-039 (BLE refinements), ADR-049 (security primitives), ADR-059 (translator / cross-transport bridging) — these live in peat/docs/adr/ (sibling repo). Local ADRs cover peat-btle's internal architecture (trust model, provisioning, document registry).

Scope

In scope:

BLE transport implementations and the platform adapter layer (src/platform/)
Peer state, advertisement, scan, GATT
BleTranslator wire codec (translator-codec feature) — the typed BLE structs, JSON projection helpers, and 0xB6 framing. peat-mesh's Translator-trait integration on top of these primitives lives in peat-mesh's tree (Slice 4.a), not here.
UniFFI surface (uniffi feature) and the Android AAR build
Feature-flag wiring in Cargo.toml

Out of scope (route elsewhere):

Mesh routing / topology / discovery / sync → peat-mesh/SKILL.md
ATAK plugin lifecycle / Android UI → peat-atak-plugin/SKILL.md
Top-level shared types/traits — consider whether the change belongs in peat/peat-protocol or peat/peat-transport (workspace subcrates of the peat repo) instead

Workflow

Orient. Read peat/SKILL.md (ecosystem) if accessible. Read this file. Read CONTRIBUTING.md for the per-platform build matrix. git status, git log -10.
Locate the spec. Confirm the task has a GitHub issue with Context / Scope / Acceptance / Constraints / Dependencies. If not, stop and ask the user.
Plan. Produce a 1–5 step plan. Cross-check against ecosystem hard invariants (transport agnosticism, FFI direction, dependency direction) and the scope guards below. If the change is architectural, reference the relevant ecosystem ADR.
Implement. Branch from main per the trunk-based convention. Vertical slices, one concern per commit. Match existing module boundaries — keep platform-specific code under src/platform/<os>/ and not in shared code paths.
Verify. Run every command in the verification checklist below. Capture output.
Hand off. Open PR against main referencing the issue. Single concern per PR — squash-merge applies, so the PR title becomes the merge commit subject.

Verification (exit criteria)

A session in this repo is not done until each of these produces evidence:

cargo fmt --check exits 0
cargo clippy -- -D warnings exits 0
cargo test exits 0 on the host platform
For platform-specific changes: cargo build --features <flag> for each affected platform feature (linux, macos, ios, android, esp32, windows) — and cargo test --features <flag> where the feature gates test code paths
For codec/translator changes: cargo test --features translator-codec
For Android AAR changes: cd android && ./gradlew assembleRelease succeeds
For UniFFI surface changes: regenerated bindings are committed in the same PR (do not let bindings drift)
If the change is functional: a behavioral test or a hardware-test plan covers the new behavior — not just unit-coverage padding

"Seems right" or "the diff looks correct" is never sufficient.

Anti-rationalization

Excuse	Rebuttal
"This change is too small to need a test."	If it's worth changing, it's worth one assertion. Add the test.
"I'll fix the clippy warning later."	The CI gate is `-D warnings`. There is no later. Fix it before commit.
"I only changed shared code; the per-platform builds will pass."	BLE platform code interacts non-obviously with feature flags and target dependencies. Build each affected platform locally.
"I'll regenerate the UniFFI bindings in a follow-up."	Stale bindings break the ATAK plugin's AAR consumption and the Android CI gate. Regenerate and commit in the same PR.
"I'll bump the version to drop the `-rc` suffix to clean up."	peat-btle is in an active RC cycle and downstream M5Stack/ESP32 firmware pins specific RCs (see the peat repo's "M5Stack peat-btle dep gate" CI check). Don't bump versions casually.
"Cargo.lock churn is noise."	peat-btle commits `Cargo.lock` because downstream consumers pin against this crate's resolved deps. Lockfile changes ride along with version bumps; don't strip them.
"Transport-level retry can live in peat-mesh's adapter — same trait."	peat-btle is the transport adapter for BLE. Retry semantics specific to BLE link characteristics (advertise window, GATT timeouts, paired-vs-unpaired) belong here, not in `peat-mesh`.
"Re-introduce the `mesh-translator` feature so peat-btle can host the `Translator` impl directly."	Don't. ADR-059 Amendment 4 Slice 4.b deleted that feature precisely to break the `peat-mesh ⇄ peat-btle` cycle. peat-mesh's tree is the home for `Translator` impls now.

Scope guards

Touch only files the issue/user asked you to touch.
Do not edit other peat-* repos. Cross-repo work goes in a separate PR in that repo, linked through a tracking issue.
Keep platform-specific code under src/platform/<os>/. Shared code must compile on every supported platform feature.
Do not bleed app-layer logic (mesh sync, document state, broker concerns) into BLE transport — those belong in peat-mesh or peat-protocol.
Do not break the Android AAR build silently. If you touch the UniFFI surface, regenerate bindings and run ./gradlew assembleRelease.
Do not configure git to bypass GPG signing or use --no-verify to skip pre-commit hooks.

Gotchas

Add an entry each time a session produces output that needed correction. One line per gotcha plus a Why: line.

(none recorded yet)

References (read on demand, not by default)

Ecosystem invariants: peat/SKILL.md (sibling repo)
Build matrix and feature flags: CONTRIBUTING.md
Quickstart guide: peat-btle-quickstart-guide.md
M5Stack/Samsung integration test plan: peat-btle-m5stack-samsung-test-plan.md
Implementation kickstart: peat-btle-implementation-kickstart.md
Cross-compilation: Cross.toml
Local ADR index: docs/adr/ — covers peat-btle's internal architecture (trust, provisioning, document registry). Numbering is inconsistent across the existing files (001-, 03-, 04-, ADR-001-, etc.) — match the existing convention if adding new ones, or normalize as a separate cleanup PR.
Ecosystem ADR index: peat/docs/adr/ (sibling repo) — ADR-032 (pluggable transport), ADR-039 (BLE refinements), ADR-049 (security primitives), ADR-059 (translator / cross-transport bridging) and others; cited in this repo's Cargo.toml comments and recent commits
Repo: https://github.com/defenseunicorns/peat-btle

Last updated: 2026-05-05 Maintained by: Kit Plummer, VP Data and Autonomy, Defense Unicorns

peat-btle SKILL