nordisk/facett

facett-claude — the direct-Claude conversation pane

Class: design · What it IS: the reusable facett-Elm component for a "chat with Claude" pane, extracted from nornir's welded ClaudeTab so every app (nornir · dwarves · holger) mounts ONE pane — no duplication (Law #1). Sibling how-to lives with the host; this file states only what the crate is.

Function axis

• f0 — the pane: an Elm (ClaudeModel/ClaudeMsg/update/view) bridged to Facet/Panel via impl_facet_via_elm!, so it is headless-drivable (update_json/state_json) and paints in egui.
• f1 — the model: user/assistant turns, the prompt input, the selected model (default claude-opus-4-8), the sending flag, an error slot.
• f2 — the transport seam: a ClaudeTransport trait (aliased ClaudeBackend) the host wires. The pane does NO HTTP — on Send it emits ClaudeEffect::Send{model, messages} (data); the host runs its transport (ClaudePane::deliver) and posts back ReceivedOk/ReceivedErr. Ships a built-in EchoBackend mock/echo default so the crate builds + every test drives with no network and no secrets. The transport seam's shape is byte-identical to the shared nornir-claude leaf's send_wire, so the EddaBackend<T> adapter mounts ANY leaf transport (OfflineTransport, the live HttpTransport) with zero mapping — see f4.
• f3 — coverage: robot JSON-drive test + testmatrix cell + kittest render proof.
• f4 — consumes the shared edda leaf nornir-claude (L5, DRY). WireMsg, DEFAULT_MODEL, MODELS, credential resolution (resolve_credential/Credential), the error type (ClaudeError) and the offline stub (OfflineTransport) are NOT twinned here — they are re-exported from nornir-claude (the whole leaf is re-exported as facett_claude::nornir_claude). EchoBackend now delegates to OfflineTransport::echoing() (no local echo logic); the EddaBackend<T> newtype bridges a leaf nornir_claude::ClaudeTransport into the pane seam by forwarding to send_wire. The pane stays the ONLY egui-facing piece (L5a); all transport/credential logic lives in the network-free leaf. The live HttpTransport is pulled by the HOST (leaf http feature), so this crate keeps no reqwest edge.

Why no nornir / reqwest edge

Apps depend on this crate, so it must not depend on nornir (cycle) and stays a pure leaf — the Anthropic HTTP client (viz::claude::HttpTransport, reqwest, claude-opus-4-8, $ANTHROPIC_API_KEY) is injected by the host. Mirrors the facett-brokkrview/facett-korp shape. A fake transport drives the tests offline — no network, no AI in the loop.

Remote-control (the north-star)

The whole conversation is drivable IN CODE over the update_json/state_json seam (prompt_changed → send → the host posts received_ok → assert last_assistant), so the robot harness + test-matrix cover it with no human and no AI at runtime.

Data / control flow

See assets/claude-pane.svg.

Sibling docs

• guide.md (class guide) — how a host mounts the pane + wires a backend.
• reasoning.md (class reasoning) — the why (idiot-guide): why no HTTP in the pane, why the seam + echo default, why everything routes through update_json.

Hosts (to wire)

• dwarves — the 🤖 Claude tab (the third pane: Pipeline · Funnel · Claude).
• nornir — de-weld src/viz/claude_tab.rs to mount this crate (follow-up).