Shared transcript-core

Per-provider store locations, record parsing, and structural filtering for Claude Code, Codex, and Cursor start in src/shared/transcript/runtimes.ts. Cursor's reliability contract adds two canonical modules beside it:

• src/shared/transcript/cursor-frames.ts streams physical JSONL frames, preserving closed, blank, malformed, partial, repaired, and replaced boundaries plus file identity and prefix-verification evidence.
• src/shared/transcript/cursor-analysis.ts assembles turns and separates prefix-stable content availability from terminal lifecycle outcomes.

The additive activity layer lives under src/shared/transcript/activity/. It extracts provider evidence, correlates only on recorded identity, and projects a bounded activitySchemaVersion: 1 report. Its source model keeps physical-line or frame/block locators, native ownership, outcome evidence, unread coverage, and diagnostics separate from presentation.

Rather than cross-skill runtime imports, each consumer ships committed generated copies under its own scripts/lib/. pnpm run build materializes those copies, so each skill remains dependency-free and install-free while tracing back to canonical TypeScript.

Consumers

Current consumers of the shared transcript-core:

• session-observer — ships runtimes.mjs, cursor-frames.mjs, and cursor-analysis.mjs, plus its generated digest, locate, observe, state, and watch pipeline.
• session-export-transcript — ships runtimes.mjs, cursor-frames.mjs, and cursor-analysis.mjs.
• session-fork-to-destination — ships a single generated alpha guidance bundle that reuses bounded transcript discovery and sanitized preview logic. Its public commands are limited to discover, preview, and prepare; it does not import or expose the older executor, reconciliation, or behavior gate.
• session-search — ships runtimes.mjs for store paths and slug handling, plus its own read-only history, metadata, and content adapters. It also bundles the hidden-payload matchers from session-export-transcript's sanitizer so injected context never counts as user-typed text.

The lower-level Cursor normalizer remains terminal-only for Export Session Transcript compatibility. Session Observer explicitly requests the content-first observation projection. Collaborative Observer explicitly requests confirmed-completion from the observer-generated modules; its control, hook, completion, and lease files remain authored JavaScript.

Schema and position semantics

The public digest is a discriminated union:

• Schema v1 keeps existing non-Cursor behavior and zero-based-jsonl-record-index accounting.
• Cursor schema v2 uses zero-based-jsonl-frame-index. fromIndex is inclusive, nextIndex is the first unconsumed safe frame, and toIndex is nextIndex - 1 or null. An entry's recordIndex is its delivery frame; sourceFrameIndex retains the original content frame.

Consumers dispatch on both fields. They never infer an index base from the runtime name or convert a persisted record position into a frame position. Cursor observation may expose stable content with lifecycle pending, while the completion projection remains terminal-success-only.

Activity projection and delivery

Observer and exporter consumers opt in explicitly. With activity disabled they keep their established conversation-only paths. With it enabled, each consumer takes one source snapshot or Cursor scan and derives conversation and activity from the same capture.

The projection modes have fixed independent envelopes:

Reports preserve counts at captured-source, delivered-range, and displayed scope. Whole evidence groups are removed when invocation or rendered-byte limits apply, with global omission counts retained. If a delivered result joins to a call outside the half-open delivery range, callContexts can carry a separately bounded outside-delivered-range preview.

Claude Code and Codex stateful delivery uses decoded record positions. Cursor uses physical frame positions and holds open-turn calls until the terminal checkpoint settles. Settlement may create an activity-only watch delta without replaying conversation. Stateless Cursor review and export can include both settled and snapshot-visible pending-lifecycle calls for retrospective review.

The activity layer does not open persisted-output files, Cursor agent-tools/, or child transcripts. It represents known references as not-read coverage; Cursor results remain not-recorded. An extraction exception becomes explicit record-activity: not-read coverage and an ACTIVITY_EXTRACTION_ERROR diagnostic. These distinctions prevent missing or unread evidence from becoming a false no-activity claim.

Activity output is labelled sensitive because bounded previews can still carry commands, paths, identifiers, inputs, and results. The exporter's conversation sanitizer does not sanitize this opt-in debug appendix.

Session Fork to Destination keeps provider capability evidence separate from transcript qualification. It preserves provider and surface in qualified candidate IDs, applies bounded discovery options to Claude Code, Codex, and Cursor, and fails closed when a Cursor transcript cannot be corroborated as CLI or IDE. Guidance preparation validates canonical Git paths and emits commands; it never invokes a provider or mutates a provider store.

Editing the source

Edit shared parsing under src/shared/transcript/ or the owning skill under src/skills/<name>/src/, then run pnpm run build to update every declared committed output.

The drift guard makes skipping the rebuild a hard error: pnpm run build:check regenerates expected output in check mode and fails on any divergence, and the same guard runs in pnpm test through tests/tooling/generated-output-sync.test.ts. Editing the canonical module without rebuilding the generated output breaks the suite.