# Richer agent transcripts + lifecycle data for observability (Langfuse / stop hooks) **URL:** \ **Category:** Feature Requests\ **Tags:** cli, hooks, cloud-agents\ **Created:** [July 24, 2026, 11:43pm UTC](https://forum.cursor.com/t/richer-agent-transcripts-lifecycle-data-for-observability-langfuse-stop-hooks/166592 "2026-07-24T23:43:35Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Martin\_Kaiser](https://avatars.discourse-cdn.com/v4/letter/m/e8c25b/32.png) [@Martin\_Kaiser](https://forum.cursor.com/u/Martin_Kaiser)\ **Post date:** [July 24, 2026, 11:43pm UTC](https://forum.cursor.com/t/richer-agent-transcripts-lifecycle-data-for-observability-langfuse-stop-hooks/166592/1 "2026-07-24T23:43:35Z")
### Feature request for product/service Cursor CLI ### Describe the request ## Feature request: richer agent transcripts + lifecycle data for observability **Context.** We’re replaying Cursor agent sessions into Langfuse via the `stop` hook + on-disk transcript (`~/.cursor/projects/.../agent-transcripts/`). That pattern works (zero SDK in the request path), but Cursor’s transcript is much thinner than Claude Code’s JSONL, so traces are incomplete. **What already works well** - `stop` fires in local CLI + IDE and includes `conversation_id`, `transcript_path`, `model` / `model_id` / `model_params` - Transcript has user/assistant text and `tool_use` (name + input) - Nested layouts for transcripts are discoverable **What we can’t get today (and why it matters)** | Gap | Impact on Langfuse / evals | |—|—| | No per-row timestamps | Waterfall timings are synthetic; can’t measure real tool latency or turn duration | | No token / cache usage | No cost dashboards, no model cost comparison | | No `tool_result` / tool outputs | Tool spans are input-only; can’t debug failures or build eval datasets from real tool I/O | | No message / tool-call IDs | Hard to join tool\_use ↔ tool\_result, hard to dedupe | | Model only on `stop`, not on transcript rows | If several turns flush in one `stop`, older turns get the _current_ model | | `afterAgentResponse` / `afterAgentThought` not in CLI | Can’t stream mid-turn text/thinking into observability without stdout hacks | | Cloud agents: lifecycle hooks historically incomplete | Same setup doesn’t cover Cloud the same way as local | | No project env injection into hooks | Secrets/config need sidecar files; Claude Code’s `settings.local.json` env is cleaner | * * * ### Ask 1 — Enrich the conversation transcript (highest value) Emit one JSONL object per event with a stable schema, e.g.: ```json { "type": "user" | "assistant" | "tool_result" | "turn_ended", "id": "msg_…", "timestamp": "2026-07-24T22:00:00.123Z", "role": "user" | "assistant" | "tool", "model": "claude-opus-4-8-thinking-high", "model_id": "claude-opus-4-8", "message": { "id": "msg_…", "content": [ { "type": "text", "text": "…" }, { "type": "tool_use", "id": "toolu_…", "name": "Shell", "input": { } }, { "type": "tool_result", "tool_use_id": "toolu_…", "content": "…", "is_error": false } ], "usage": { "input_tokens": 0, "output_tokens": 0, "cache_read_input_tokens": 0, "cache_creation_input_tokens": 0 } } } ``` **Minimum viable fields (in priority order):** 1. ISO timestamps on every row 2. `usage` on assistant rows (input/output + cache if available) 3. `tool_result` rows (or blocks) with `tool_use_id` + truncated output + error flag 4. Stable `id` on messages and `tool_use` 5. `model` / `model_id` on each assistant row (not only on `stop`) Optional but useful: thinking blocks (or a redacted length/hash), request/generation id matching the hook payload’s `generation_id`. * * * ### Ask 2 — Flush transcript before `stop` (or document a ready signal) Today `stop` can fire before the last turn’s lines are on disk, so hooks must poll. Prefer: - Flush + fsync transcript before invoking `stop`, **or** - Add `"transcript_ready": true` / `transcript_byte_size` on the `stop` payload so hooks don’t guess * * * ### Ask 3 — CLI / Cloud hook parity - Fire `afterAgentResponse` and `afterAgentThought` in headless CLI (`agent --print`) the same as IDE - Fire lifecycle hooks (`sessionStart`, `stop`, `afterAgentResponse`) on Cloud agents with the same payload shape as local - Keep `stop` as the reliable “turn complete” signal; don’t make observability depend only on tool hooks * * * ### Ask 4 — Hook config / secrets ergonomics - Allow project-scoped env for hooks (similar to Claude Code `settings.local.json` → `env`), or document a supported secrets path - Keep `transcript_path` always absolute and non-null when transcripts are enabled; document nested vs flat transcript layouts as a stable contract * * * ### Ask 5 — Privacy controls (so richer data is shippable) If richer transcripts raise privacy concerns, ship toggles rather than omitting fields entirely: - `transcript.include_tool_results`: off | truncated | full - `transcript.include_usage`: on/off - `transcript.max_tool_result_chars`: N Default can stay conservative; power users / teams can opt into observability fidelity. * * * ### Why this matters With the fields above, third-party hooks can produce Langfuse-quality traces **without instrumenting the agent or proxying model calls**: real waterfalls, real cost, joinable tool I/O, and accurate per-turn model tags — the same bar Claude Code already enables via its Stop-hook + JSONL transcript design. Happy to share a sample of current vs desired JSONL from local `agent-transcripts/` if useful. ---
**Author:** ![deanrie](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/deanrie/32/1263_2.png) [@deanrie](https://forum.cursor.com/u/deanrie)\ **Post date:** [July 26, 2026, 5:49pm UTC](https://forum.cursor.com/t/richer-agent-transcripts-lifecycle-data-for-observability-langfuse-stop-hooks/166592/5 "2026-07-26T17:49:50Z")
Hey, thanks for such a well thought-out request. The Ask 1 to 5 breakdown with an example of the desired JSONL schema is exactly the level of detail we need. I’ve forwarded it as a feature request. I also want to clarify the status on a few items so you don’t build a pipeline on the wrong expectations: - `stop` payload: it fires in local CLI plus IDE and includes `conversation_id`, `transcript_path`, `model` or `model_id` or `model_params`. Token usage `input_tokens`, `output_tokens`, `cache_*` is not included in the `stop` payload right now. That’s one of the key points in your request and it’s tracked. - Token usage, thinking, and assistant message are available today via headless `--print` with `--output-format stream-json`. The final `result` event includes token usage and the request ID, and along the way you also get thinking deltas and the full assistant message. For cost dashboards and trace reconstruction, this is a workable interim option without transcript enrichment. - `afterAgentResponse` and `afterAgentThought`: these do not fire in CLI right now, neither headless nor interactive. This is a known gap, see [Hooks afterAgentResponse / afterAgentThought not firing in headless CLI](https://forum.cursor.com/t/hooks-afteragentresponse-afteragentthought-not-firing-in-headless-cli/156220). They work in the IDE. - Env for hooks Ask 4: the `sessionStart` hook response can set env for later hook calls in the session, but there are important caveats. Subagents do not inherit that env, see [SubAgents do not inherit environment variables](https://forum.cursor.com/t/subagents-do-not-inherit-environment-variables/155212), and variables are lost when you close and reopen a chat or restart Cursor. `sessionStart` is not replayed on resume, see [Env exported in sessionStart hook does not persist across Cursor restarts](https://forum.cursor.com/t/env-exported-in-sessionstart-hook-does-not-persist-across-cursor-restarts/157196). So as a channel for persistent secrets it’s not reliable right now. Sidecar files are the more honest option for now. On the main asks, Ask 1 transcript schema enrichment, per-row timestamps, `usage`, `tool_result` with `tool_use_id`, stable IDs, per-row model, and Ask 2 flush or ready signal before `stop`, there’s no implementation timeline yet. The request is logged in that form. Also, a sample current vs desired JSONL from your local `agent-transcripts/` would be helpful. If you can share it here, it’ll help us pin down the minimum viable schema more precisely. ---
**Author:** ![Martin\_Kaiser](https://avatars.discourse-cdn.com/v4/letter/m/e8c25b/32.png) [@Martin\_Kaiser](https://forum.cursor.com/u/Martin_Kaiser)\ **Post date:** [July 27, 2026, 1:07am UTC](https://forum.cursor.com/t/richer-agent-transcripts-lifecycle-data-for-observability-langfuse-stop-hooks/166592/7 "2026-07-27T01:07:45Z")
Thanks for the clarifications — really helpful so we don’t build on the wrong contract. Quick confirmations from our side: - We’ll keep treating **sidecar files** (e.g. `.cursor/langfuse.env`) as the honest path for secrets/opt-in, given the `sessionStart` env caveats (subagents, restart/resume). - For **cost / usage / thinking** , we’ll treat `agent --print --output-format stream-json` as the interim path (final `result` + thinking/assistant events), separate from the `stop` + transcript path. - We’ll keep relying on **`stop`** for local CLI + IDE turn completion, and not on `afterAgentResponse` / `afterAgentThought` in CLI. Below is a **current vs desired** sample from a real local transcript (paths redacted). Source layout: `~/.cursor/projects//agent-transcripts//.jsonl` ### Current (actual rows from `agent-transcripts/`) Full-file stats for one conversation (87 rows): - top-level keys are only `role` + `message` (no `timestamp`, no `type` control rows in this file) - `message` keys are only `content` (no `id`, no `usage`, no `model`) - content blocks are only `text` and `tool_use` - every `tool_use` has keys exactly: `type`, `name`, `input` — **no `id`** - **0** `tool_result` blocks, **0** usage fields, **0** timestamps, **0** message ids Example (redacted / truncated): ```jsonl {"role":"user","message":{"content":[{"type":"text","text":"Thursday, Jul 23, 2026, 11:20 PM (UTC+2)\n\n• For Cursor, do you want full automatic Langfuse tracing…"}]}} {"role":"assistant","message":{"content":[{"type":"text","text":"I'll look at the current state of the project…"},{"type":"tool_use","name":"Shell","input":{"command":"ls -la && echo \"---DOCS---\" && ls -la docs","description":"List project structure"}},{"type":"tool_use","name":"Glob","input":{"glob_pattern":"**/*cursor*"}}]}} {"role":"assistant","message":{"content":[{"type":"tool_use","name":"Read","input":{"path":"/Users//.../README.md"}},{"type":"tool_use","name":"Shell","input":{"command":"ls -la hooks","description":"Inspect hooks"}}]}} {"role":"assistant","message":{"content":[{"type":"text","text":"I dug into the current state…"},{"type" :"tool_use","name":"AskQuestion","input":{"questions":[{"id":"cursor_path","prompt":"Which do you want me to do for Cursor?","options":[{"id":"docs_first","label":"docs/cursor.md first…"},{"id":"full_auto","label":"Full automatic tracing now…"}]}]}}]}} ``` Note: some older sessions also had a control row like `{"type":"turn_ended","status":"success"}`; this newer file has none. Worth treating that as optional/unstable until the schema is formalized. ### Desired (minimum viable for Langfuse-quality stop-hook replay) Same turn, enriched so a `stop` hook can emit real waterfalls + cost + joinable tools without pairing `stream-json`: ```jsonl {"type":"user","id":"msg_u1","timestamp":"2026-07-23T21:20:00.120Z","role":"user","message":{"id":"msg_u 1","content":[{"type":"text","text":"…"}]}} {"type":"assistant","id":"msg_a1","timestamp":"2026-07-23T21:20:01.450Z","role":"assistant","model":"cla ude-opus-4-8-thinking-high","model_id":"claude-opus-4-8","message":{"id":"msg_a1","content":[{"type":"te xt","text":"I'll look at the current state of the project…"},{"type":"tool_use","id":"toolu_1","name":"Shell","input":{"command":"ls -la","description":"List project structure"}},{"type":"tool_use","id":"toolu_2","name":"Glob","input":{" glob_pattern":"**/*cursor*"}}],"usage":{"input_tokens":18240,"output_tokens":312,"cache_read_input_token s":12000,"cache_creation_input_tokens":800}}} {"type":"tool_result","id":"msg_tr1","timestamp":"2026-07-23T21:20:01.820Z","tool_use_id":"toolu_1","con tent":"total 56\ndrwxr-xr-x …","is_error":false} {"type":"tool_result","id":"msg_tr2","timestamp":"2026-07-23T21:20:01.910Z","tool_use_id":"toolu_2","con tent":"[\"hooks/cursor_langfuse_hook.py\", …]","is_error":false} {"type":"assistant","id":"msg_a2","timestamp":"2026-07-23T21:20:03.100Z","role":"assistant","model":"cla ude-opus-4-8-thinking-high","model_id":"claude-opus-4-8","message":{"id":"msg_a2","content":[{"type":"te xt","text":"I dug into the current state…"}],"usage":{"input_tokens":19102,"output_tokens":840,"cache_re ad_input_tokens":15000,"cache_creation_input_tokens":0}}} {"type":"turn_ended","timestamp":"2026-07-23T21:20:03.200Z","status":"success","generation_id":"gen_…"} ``` ### Minimum fields that unblock us (priority order) 1. ISO `timestamp` on every row 2. `usage` on assistant rows (`input_tokens` / `output_tokens` / cache\_\*) 3. `tool_result` with `tool_use_id` (+ truncated `content`, `is_error`) 4. Stable `id` on messages and `tool_use` 5. `model` / `model_id` on each assistant row (not only on `stop`) Plus Ask 2: flush / `transcript_ready` (or `transcript_byte_size`) before `stop` so hooks don’t race the async write. Happy to share a longer redacted file privately if useful. Thanks again for logging Ask 1–5 and for the interim `stream-json` guidance. ──────────────────────────────────────── Implication for our hook: stay on stop + transcript; don’t rely on CLI afterAgentResponse or sessionStart env for secrets. Optional later: a CLI stream-json sidecar for usage/cost when people run headless. ---
**Author:** ![deanrie](https://sea3.discourse-cdn.com/cursor1/user_avatar/forum.cursor.com/deanrie/32/1263_2.png) [@deanrie](https://forum.cursor.com/u/deanrie)\ **Post date:** [July 27, 2026, 6:15am UTC](https://forum.cursor.com/t/richer-agent-transcripts-lifecycle-data-for-observability-langfuse-stop-hooks/166592/8 "2026-07-27T06:15:40Z")
Thanks for the sample. Comparing current vs desired on a real file really helps lock down the minimum viable schema. I added it to the request along with the prioritized field list ISO `timestamp` on every row, `usage` on assistant rows, `tool_result` with `tool_use_id`, stable `id`, and per-row `model`, plus Ask 2 flush, `transcript_ready`, and `transcript_byte_size` before `stop`. Your three working assumptions are correct at the moment: - Sidecar files like `.cursor/langfuse.env` are a reliable way to handle secrets and opt-in, given the caveats with `sessionStart` env variables sub-agents, restart, and resume. - `agent --print --output-format stream-json` is a valid interim solution for usage, cost, and thinking the final `result` event plus thinking and assistant events, separate from `stop` plus the transcript. - `stop` is for turn completion in the local CLI and IDE, without relying on `afterAgentResponse` or `afterAgentThought` in the CLI. On the main items Ask 1 schema enrichment and Ask 2 flush and ready signal there’s no implementation timeline yet. The request is recorded in this form. If needed, you can share a longer redacted file, it won’t hurt. If you hit any more contract mismatches while working on the hook, message me here.