The Chat Pane Learns to Reply
Joining a fully built but isolated chat backend to the running engine, so a typed message finally gets an answer.
0 milestones 1 sprints
36m 20s total 27m 44s per sprint
12.2M tokens in 128k tokens out
$13.32 nominal cost
The chat pane could accept a typed message and render it, but the live build never handed that message to the assistant machinery already present in the backend. This job joined the command router, transcript, assistant turn runner, run-scoped tool host, and reply events at the build engine boundary, so the pane became a working support console beside the deterministic run.
How this walkthrough is structured
Feature
What did the run build and ship?
A typed chat message now reaches an assistant running beside the build, while prompt answers still resolve through the original path and idle runs keep their old event shape.
Build
How did Gantry structure the work?
The job was cut as a single integration sprint because the backend parts already existed, leaving the fresh agent to own the channel split, event fan-out, and live-engine handoff as one bounded wiring problem.
Wire Chat Console
0 agents 27m 44s wall time 114.9k tokens out $11.47 nominal cost
The live tree still carries the connection, though later work renamed the brain surface to the assistant and split the old build file into a module directory. `BuildEngine` stands the console up beside the run, hands the prompt primitive an internal answer-only receiver, and lets the chat layer own the front-end command channel. `src/engine/chat.rs` contains the demux and fan-out: prompt answers pass through untouched, user messages become assistant turns, prompt resolution events are observed by the run-scoped tool host, and reply events return to the front-end. `src/engine/assistant.rs` and `src/engine/transcript.rs` still provide the turn driver and persisted conversation record that make the reply auditable across turns.
The brief made this a wiring sprint rather than a component build: the turn runner, transcript, command router, tool host, and reply rendering were already present and tested apart. That left a fresh agent with one coherent boundary to hold, the point where the front-end command channel enters the build engine. The hard part was not the assistant reply itself, but feeding the same live event stream to both the front-end and the assistant host without taking prompt handling away from the engine. The run record shows no repair pass, retry, or re-plan attached to the sprint, which fits a cut where the unbuilt coupling was explicit before work began.