FE-735: Mode shell and fixture driver (M1) by lunelson · Pull Request #144 · hashintel/brunch

lunelson · 2026-05-21T10:10:51Z

FE-735: Add print snapshot transport shell

FE-735: Add named JSON-RPC stdio skeleton

FE-735: Project elicitation exchanges from JSONL

FE-735: Project real Pi JSONL exchanges

FE-735: Scope session exchange RPC to current session

FE-735: Add RPC print snapshot parity smoke

FE-735: Add fixture capture bundle skeleton

FE-735: Seed deterministic fixture briefs

FE-735: Scope capture seam review fixes

FE-735: Stabilize current session capture

FE-735: Reconcile fixture brief format docs

FE-735: Use Pi session entry types for exchange projection

FE-735: Report Brunch-owned fixture metadata version

FE-735: Capture scripted brief runs

lunelson · 2026-05-21T10:11:08Z

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cursor · 2026-05-27T16:31:06Z

PR Summary

Medium Risk
Headless boot and session reopen semantics changed for RPC/print/capture; impact is mitigated by broad tests and runbook checks, but wrong session selection would break replay fixtures.

Overview
M1 mode shell and first fixture driver land on the same Brunch host as the TUI: brunch --mode print renders a workspace snapshot and exits without an agent turn; brunch --mode rpc serves newline-delimited JSON-RPC with workspace.snapshot and session.elicitationExchanges (coordinator-selected session only, no raw file params).

New elicitation exchange projection derives prompt/response spans from Pi JSONL (assistant, tool results, structured prompts/responses). Fixture capture copies the selected session transcript plus Brunch-owned .meta.json (projection summary, deferred graph/coherence); a scripted-deterministic path seeds briefs #1–#3 as JSON under .brunch-fixtures/ with committed scripted-001 replay bundles.

Workspace session coordinator now persists currentSessionFile, reopens the selected session on headless paths, and supports createNewSpec for per-brief captures. Planning/docs mark mode-shell-and-fixture-driver complete and advance active work to jsonl-session-viability; fixture strategy and SPEC clarify transport vs agent modes and JSON brief format. ./runbooks/verify-m1.sh plus unit/integration tests cover RPC, print/RPC parity, capture, and replay projection parity.

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augmentcode · 2026-05-27T16:34:50Z

🤖 Augment PR Summary

Summary: This PR delivers M1 “mode shell + fixture driver” support by adding headless transport modes and the first deterministic fixture capture loop.

Changes:

Adds runBrunchCli() with --mode print (snapshot-only) and --mode rpc (newline JSON-RPC over stdio), while keeping TUI mode intact.
Introduces a product-shaped WorkspaceSnapshot projection and a human-readable print renderer.
Adds a minimal JSON-RPC adapter with named methods (workspace.snapshot, session.elicitationExchanges) scoped to the coordinator-selected session.
Implements elicitation-exchange projection over Pi JSONL transcripts and disk loader utilities.
Adds fixture brief library loading (JSON briefs) and a fixture capture path that writes .jsonl + .meta.json bundles.
Seeds three deterministic briefs and commits scripted capture bundles under .brunch-fixtures/.
Extends the workspace session coordinator to persist/reopen the selected session file via .brunch/state.json.
Adds a runbook (runbooks/verify-m1.sh) plus unit tests covering print/RPC parity and fixture replay/projection parity.

Technical notes: The RPC surface is intentionally thin (named method families over projections), and print mode is treated as a transport proof-of-life rather than an agent turn.

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augmentcode

Review completed. 2 suggestions posted.

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augmentcode · 2026-05-27T16:35:15Z

+): Promise<WorkspaceSessionReadyState["session"]> {
+  await ensureWorkspaceDirs(cwd)
+  const files = await listSessionFiles(cwd)
+  const manager = currentSessionFile


currentSessionFile is read from .brunch/state.json, so a stale/tampered path here can throw (breaking print/RPC) and also cause bindSessionToSpec to rewrite an unexpected file. Consider guarding that it exists and is within .brunch/sessions/ (and falling back when invalid) before calling SessionManager.open().

Severity: medium

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augmentcode · 2026-05-27T16:35:15Z

+}
+
+function isPromptSideEntry(entry: SessionEntry): boolean {
+  if (isCustomTranscriptEntry(entry) && entry.customType.includes("prompt")) {


isPromptSideEntry() only treats custom(_message) entries as prompt-side when customType contains "prompt", so other model-visible injected custom_message entries (e.g. brunch/world_update/v1) would be omitted from promptEntryIds/ranges. If those injections are meant to be part of the prompt span between user turns, the current projection will silently drop them.

Severity: medium

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cursor

Cursor Bugbot has reviewed your changes and found 2 potential issues.

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cursor · 2026-05-27T16:38:02Z

+
+  const role = roleOf(entry)
+  return role === "assistant" || role === "toolResult"
+}


Prompt-side classification uses fragile substring match

Medium Severity

isPromptSideEntry uses customType.includes("prompt") as a substring match, while isResponseSideEntry uses an explicit Set (STRUCTURED_RESPONSE_TYPES). This asymmetry means any future custom entry type containing "prompt" anywhere in its name (e.g. brunch.prompt_history, brunch.user_prompt_feedback) would silently be classified as prompt-side, potentially corrupting exchange projections. The response side is already guarded against this with an allowlist pattern.

Additional Locations (1)

src/elicitation-exchange.ts#L10-L15

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graphite-app · 2026-06-02T17:29:34Z

Merge activity

Jun 2, 5:29 PM UTC: Graphite rebased this pull request, because this pull request is set to merge when ready.

This was referenced May 21, 2026

FE-702: Walking skeleton — brunch binary + TUI over pi (M0) #142

Merged

FE-736: JSONL session viability proof (M2) #146

Merged

FE-737: Web shell over the same host (M3) #147

Merged

FE-744: Document Pi command containment evidence #150

Merged

lunelson changed the title ~~FE-735: Add print snapshot transport shell~~ FE-735: Mode shell and fixture driver (M1) May 27, 2026

lunelson marked this pull request as ready for review May 27, 2026 16:31

augmentcode Bot reviewed May 27, 2026

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cursor Bot reviewed May 27, 2026

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This was referenced Jun 1, 2026

FE-776: Graph Layer preps #162

Merged

FE-785: M5 agent-graph-integration #163

Merged

lunelson self-assigned this Jun 2, 2026

lunelson requested a review from kostandinang June 2, 2026 13:34

Base automatically changed from ln/fe-729-walking-skeleton to next June 2, 2026 17:28

lunelson added 14 commits June 2, 2026 17:28

FE-735: Add print snapshot transport shell

938a962

FE-735: Add named JSON-RPC stdio skeleton

574e515

FE-735: Project elicitation exchanges from JSONL

4c7be0e

FE-735: Project real Pi JSONL exchanges

a751960

FE-735: Scope session exchange RPC to current session

9546d5d

FE-735: Add RPC print snapshot parity smoke

6d54d7f

FE-735: Add fixture capture bundle skeleton

a236b9c

FE-735: Seed deterministic fixture briefs

7b82284

FE-735: Scope capture seam review fixes

41f8976

FE-735: Stabilize current session capture

6030ea3

FE-735: Reconcile fixture brief format docs

4c69cef

FE-735: Use Pi session entry types for exchange projection

0090693

FE-735: Report Brunch-owned fixture metadata version

084a7dc

FE-735: Capture scripted brief runs

9bf3fd5

lunelson added 4 commits June 2, 2026 17:28

FE-735: Bind scripted captures per brief

edf2ea2

FE-735: Project tool results as prompt entries

dc911d8

FE-735: Add M1 verification runbook

c5e852c

FE-735: Reconcile M1 fixture verification

eca7505

lunelson force-pushed the ln/fe-735-mode-shell-fixture-driver branch from e32eb02 to eca7505 Compare June 2, 2026 17:29

lunelson merged commit 38d2c2a into next Jun 2, 2026
6 checks passed

lunelson deleted the ln/fe-735-mode-shell-fixture-driver branch June 2, 2026 17:30

This was referenced Jun 2, 2026

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FE-735: Mode shell and fixture driver (M1)#144

FE-735: Mode shell and fixture driver (M1)#144
lunelson merged 18 commits into
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Prompt-side classification uses fragile substring match

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