# Changelog

All notable changes to DeerFlow are documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [2.0.0] — 2026-06-15

DeerFlow 2.0 is a ground-up rewrite around a "super agent" harness with
sub-agents, persistent memory, sandbox execution, and an extensible
skills/tools system. It shares no code with the 1.x line, which now lives on
the [`main-1.x` branch](https://github.com/bytedance/deer-flow/tree/main-1.x).

This release closes [milestone 2.0.0](https://github.com/bytedance/deer-flow/milestone/1)
with **102 merged pull requests** since the first 2.0 milestone tag.

### ⚠ Breaking changes

- **harness:** Hydrate runs from `RunStore` and persist interrupted status. Run
  cancellation/multitask semantics now require a working RunStore on the
  worker that owns the run; cross-worker cancels return 409 instead of
  silently appearing successful. ([#2932])

### Added

#### Agents & runtime
- **agent:** Custom-agent self-updates with user isolation — agents can persist
  edits to their own `SOUL.md` / `config.yaml` from inside a normal chat.
  ([#2713])
- **loop-detection:** Make loop detection configurable with per-tool frequency
  overrides; keep configurable on/off switch. ([#2586], [#2711])
- **loop-detection:** Defer warning injection so detector pairs cleanly with
  tool-call lifecycle. ([#2752])
- **run:** Propagate `model_name` from the gateway request through the runtime
  and persistence stack into the SQLite-backed store. ([#2775])
- **subagents:** Stream subagent token usage to the header via terminal task
  events. ([#2882])

#### Models & integrations
- **models:** Add StepFun reasoning model adapter. ([#3461])
- **community:** Add Brave Search web search tool. ([#3528])
- **channels:** Enhance Discord with mention-only mode, thread routing, and
  typing indicators. ([#2842])
- **im:** Add user-owned IM channel connections — users can bind their own
  Slack/Telegram/Discord/Feishu/DingTalk/WeChat/WeCom accounts on top of the
  operator-configured bots. ([#3487])

#### Observability
- **trace:** Set the LangGraph trace name to `lead_agent` (or the custom
  agent's `agent_name`) for cleaner Langfuse/LangSmith traces. ([#3101])
- **frontend:** Refine token usage display modes. ([#2329])
- **defaults:** Enable token usage tracking by default. ([#2841])
- **defaults:** Raise default summarization trigger threshold. ([#3174])

### Performance

- **harness:** Push thread metadata filters into SQL instead of post-filtering
  in Python. ([#2865])
- **runtime:** Index runs by `thread_id` to avoid O(n) scans in `RunManager`.
  ([#3499])
- **runtime:** Index messages in `MemoryRunEventStore` to avoid O(n) scans.
  ([#3531])

### Security

- **upload:** Reject symlinked upload destinations. ([#2623])
- **uploads:** Add Windows support for safe symlink-protected uploads.
  ([#2794])
- **mcp:** Mask sensitive values in MCP config API responses. ([#2667])
- **mcp:** Harden the MCP config endpoint against malformed input. ([#3425])
- **auth:** Reject cross-site auth POSTs. ([#2740])
- **gateway:** Cap skill artifact preview decompression to prevent
  zip-bomb-style abuse. ([#2963])

### Fixed

#### Runtime, gateway & persistence
- **runtime:** Rollback restore checkpoint now supersedes newer checkpoints.
  ([#2582])
- **runtime:** Persist run message summaries. ([#2850])
- **runtime:** Bound `write_file` execution-failure observations to keep
  failure traces from blowing out the context. ([#3133])
- **runtime:** Protect the sync singleton's init and reset paths. ([#3413])
- **runtime:** Avoid PostgreSQL aggregate `FOR UPDATE` on run events.
  ([#2962])
- **runs:** Restore historical runs from persistent store after a gateway
  restart. ([#2989])
- **gateway:** Return ISO 8601 timestamps from threads endpoints. ([#2599])
- **gateway:** Make cancel idempotent for already-interrupted runs. ([#3058])
- **gateway:** Split `stream_existing_run` into per-method routes for unique
  OpenAPI `operationId`s. ([#3228])
- **events:** Serialize structured DB event content. ([#2762])
- **persistence:** Emit timezone-aware timestamps from SQLite-backed stores.
  ([#3130])
- **persistence:** Reuse token usage model grouping expression. ([#2910])
- **runs:** Ignore stale run reconnect conflicts. ([#3284])
- **nginx:** Defer CORS to the gateway allowlist instead of double-applying it.
  ([#2861])

#### Agents, subagents & middleware
- **subagents:** Make subagent timeout terminal state atomic. ([#2583])
- **subagents:** Use model override for tools and middleware. ([#2641])
- **subagents:** Consolidate `system_prompt` and skills into a single
  `SystemMessage`. ([#2701])
- **subagent:** Isolate subagents from the parent run's checkpointer.
  ([#3559])
- **agents:** Make `update_agent` honor `runtime.context` `user_id` like
  `setup_agent` does. ([#2867])
- **agents:** Resolve duplicate `todos` channel type conflict in
  `TodoMiddleware`. ([#3200])
- **agents:** Offload blocking filesystem IO in the custom-agent router off
  the event loop. ([#3457])
- **agents:** Keep new agent bootstrap in user scope. ([#2784])
- **loop-detection:** Keep tool-call pairing on warn injection. ([#2725])
- **middleware:** Sync raw tool-call metadata. ([#2757])
- **middleware:** Handle invalid tool calls in dangling pairing middleware.
  ([#2891])
- **middleware:** Prevent todo completion reminder IM-message leak. ([#2907])
- **middleware:** Normalize tool result adjacency before model calls.
  ([#2939])

#### Memory & tracing
- **memory:** Replace short-lived `asyncio.run()` with a persistent event
  loop. ([#2627])
- **memory:** Isolate queued memory updates by agent. ([#2941])
- **memory:** Parse wrapped memory-update JSON responses. ([#3252])
- **tracing:** Propagate `session_id` and `user_id` into Langfuse traces.
  ([#2944])
- **trace:** Decode unicode escape sequences in non-ASCII memory trace info.
  ([#3104])

#### Tools, sandbox & MCP
- **mcp:** Fix env resolution in MCP config lists. ([#2556])
- **models:** Record Codex token usage in `usage_metadata`. ([#2585])
- **sandbox:** Supplement `list_running` in `RemoteSandboxBackend`. ([#2716])
- **sandbox:** Disable MSYS path conversion for Git Bash on Windows.
  ([#2766])
- **sandbox:** Avoid blocking sandbox readiness polling. ([#2822])
- **sandbox:** Uphold the `/mnt/user-data` contract at the `Sandbox` API
  boundary. ([#2881])
- **sandbox:** Scope provisioner PVC data by user. ([#2973])
- **sandbox:** Merge idempotent sandbox state updates. ([#3518])
- **tools:** Introduce `Runtime` type alias to eliminate Pydantic serialization
  warnings. ([#2774])
- **tools:** Preserve `tool_search` promotions across re-entrant
  `get_available_tools`. ([#2885])
- **harness:** Wrap async-only config tools for sync client execution.
  ([#2878])
- **harness:** Wrap all async-only tools for sync clients. ([#2935])

#### Skills & channels
- **skills:** Enforce `allowed-tools` metadata. ([#2626])
- **skills:** Harden slash skill activation across chat channels. ([#3466])
- **skills:** Fix custom skill install permissions. ([#3241])
- **channels:** Authenticate gateway command requests. ([#2742])

#### Auth
- **auth:** Replace setup-status 429 rate limit with a cached response.
  ([#2915])
- **auth:** Persist auto-generated JWT secret so it survives restarts.
  ([#2933])

#### Frontend
- **frontend:** Restore `localhost` fallback for `getGatewayConfig` in prod
  mode. ([#2718])
- **chat:** Prevent the first user message from being swallowed in new
  conversations. ([#2731])
- **frontend:** Use backend thread token usage for the header total. ([#2800])
- **frontend:** Wait for async chat submit before clearing the input.
  ([#2940])
- **frontend:** Resolve login page flickering and the resize-observer loop.
  ([#2954])
- **frontend:** Deduplicate restored thread messages. ([#2958])
- **frontend:** Avoid duplicate optimistic user message. ([#3002])
- **frontend:** Hide the copy button for streaming assistant messages.
  ([#3176])
- **frontend:** Show a new thread in the sidebar immediately on creation.
  ([#3283])
- **frontend:** Isolate new chat thread messages. ([#3508])
- **frontend:** Cap deeply nested list indentation to prevent render crashes.
  ([#3393], [#3570])
- **token-usage:** Dedupe token usage aggregation by message id. ([#2770])

#### Build, deploy, scripts & config
- **packaging:** Add `postgres` extra for store/checkpointer support; clarify
  install guidance. ([#2584])
- **harness:** Resolve runtime paths from the project root. ([#2642])
- **docker:** Force nginx to resolve upstream names at request time.
  ([#2717])
- **docker:** Default Gateway to a single worker to prevent multi-worker
  breakage. ([#3475])
- **scripts:** Preserve `uv` extras across `make dev` restarts. ([#2767],
  [#2754])
- **scripts:** Clean up local nginx on stop. ([#3005])
- **deploy:** Fall back to `python` / `openssl` when `python3` is absent for
  secret generation. ([#3074])
- **config:** Make the reload boundary discoverable from code. ([#3144],
  [#3153])
- **replay-e2e:** Key replay fixtures by caller and conversation. ([#3453])

### Changed

- **provider (refactor):** Share assistant payload replay matching across
  providers. ([#3307])

### Documentation

- Document blocking-IO detection usage and maintenance. ([#3233])
- Clean standalone LangGraph server remnants from docs. ([#3301])

### Internal

- **dev:** Add async/thread boundary detector. ([#2936])
- **runtime:** Add lifecycle end-to-end coverage. ([#2946])
- **windows:** Add `PYTHONIOENCODING` and `PYTHONUTF8` to backend Makefile
  targets. ([#3069])
- **blocking-io:** Fail-loud repo-root resolution and shared detector CLI
  shim. ([#3512])

[2.0.0]: https://github.com/bytedance/deer-flow/releases/tag/v2.0.0
[#2329]: https://github.com/bytedance/deer-flow/pull/2329
[#2556]: https://github.com/bytedance/deer-flow/pull/2556
[#2582]: https://github.com/bytedance/deer-flow/pull/2582
[#2583]: https://github.com/bytedance/deer-flow/pull/2583
[#2584]: https://github.com/bytedance/deer-flow/pull/2584
[#2585]: https://github.com/bytedance/deer-flow/pull/2585
[#2586]: https://github.com/bytedance/deer-flow/pull/2586
[#2599]: https://github.com/bytedance/deer-flow/pull/2599
[#2623]: https://github.com/bytedance/deer-flow/pull/2623
[#2626]: https://github.com/bytedance/deer-flow/pull/2626
[#2627]: https://github.com/bytedance/deer-flow/pull/2627
[#2641]: https://github.com/bytedance/deer-flow/pull/2641
[#2642]: https://github.com/bytedance/deer-flow/pull/2642
[#2667]: https://github.com/bytedance/deer-flow/pull/2667
[#2701]: https://github.com/bytedance/deer-flow/pull/2701
[#2711]: https://github.com/bytedance/deer-flow/pull/2711
[#2713]: https://github.com/bytedance/deer-flow/pull/2713
[#2716]: https://github.com/bytedance/deer-flow/pull/2716
[#2717]: https://github.com/bytedance/deer-flow/pull/2717
[#2718]: https://github.com/bytedance/deer-flow/pull/2718
[#2725]: https://github.com/bytedance/deer-flow/pull/2725
[#2731]: https://github.com/bytedance/deer-flow/pull/2731
[#2740]: https://github.com/bytedance/deer-flow/pull/2740
[#2742]: https://github.com/bytedance/deer-flow/pull/2742
[#2752]: https://github.com/bytedance/deer-flow/pull/2752
[#2754]: https://github.com/bytedance/deer-flow/pull/2754
[#2757]: https://github.com/bytedance/deer-flow/pull/2757
[#2762]: https://github.com/bytedance/deer-flow/pull/2762
[#2766]: https://github.com/bytedance/deer-flow/pull/2766
[#2767]: https://github.com/bytedance/deer-flow/pull/2767
[#2770]: https://github.com/bytedance/deer-flow/pull/2770
[#2774]: https://github.com/bytedance/deer-flow/pull/2774
[#2775]: https://github.com/bytedance/deer-flow/pull/2775
[#2784]: https://github.com/bytedance/deer-flow/pull/2784
[#2794]: https://github.com/bytedance/deer-flow/pull/2794
[#2800]: https://github.com/bytedance/deer-flow/pull/2800
[#2822]: https://github.com/bytedance/deer-flow/pull/2822
[#2841]: https://github.com/bytedance/deer-flow/pull/2841
[#2842]: https://github.com/bytedance/deer-flow/pull/2842
[#2850]: https://github.com/bytedance/deer-flow/pull/2850
[#2861]: https://github.com/bytedance/deer-flow/pull/2861
[#2865]: https://github.com/bytedance/deer-flow/pull/2865
[#2867]: https://github.com/bytedance/deer-flow/pull/2867
[#2878]: https://github.com/bytedance/deer-flow/pull/2878
[#2881]: https://github.com/bytedance/deer-flow/pull/2881
[#2882]: https://github.com/bytedance/deer-flow/pull/2882
[#2885]: https://github.com/bytedance/deer-flow/pull/2885
[#2891]: https://github.com/bytedance/deer-flow/pull/2891
[#2907]: https://github.com/bytedance/deer-flow/pull/2907
[#2910]: https://github.com/bytedance/deer-flow/pull/2910
[#2915]: https://github.com/bytedance/deer-flow/pull/2915
[#2932]: https://github.com/bytedance/deer-flow/pull/2932
[#2933]: https://github.com/bytedance/deer-flow/pull/2933
[#2935]: https://github.com/bytedance/deer-flow/pull/2935
[#2936]: https://github.com/bytedance/deer-flow/pull/2936
[#2939]: https://github.com/bytedance/deer-flow/pull/2939
[#2940]: https://github.com/bytedance/deer-flow/pull/2940
[#2941]: https://github.com/bytedance/deer-flow/pull/2941
[#2944]: https://github.com/bytedance/deer-flow/pull/2944
[#2946]: https://github.com/bytedance/deer-flow/pull/2946
[#2954]: https://github.com/bytedance/deer-flow/pull/2954
[#2958]: https://github.com/bytedance/deer-flow/pull/2958
[#2962]: https://github.com/bytedance/deer-flow/pull/2962
[#2963]: https://github.com/bytedance/deer-flow/pull/2963
[#2973]: https://github.com/bytedance/deer-flow/pull/2973
[#2989]: https://github.com/bytedance/deer-flow/pull/2989
[#3002]: https://github.com/bytedance/deer-flow/pull/3002
[#3005]: https://github.com/bytedance/deer-flow/pull/3005
[#3058]: https://github.com/bytedance/deer-flow/pull/3058
[#3069]: https://github.com/bytedance/deer-flow/pull/3069
[#3074]: https://github.com/bytedance/deer-flow/pull/3074
[#3101]: https://github.com/bytedance/deer-flow/pull/3101
[#3104]: https://github.com/bytedance/deer-flow/pull/3104
[#3130]: https://github.com/bytedance/deer-flow/pull/3130
[#3133]: https://github.com/bytedance/deer-flow/pull/3133
[#3144]: https://github.com/bytedance/deer-flow/pull/3144
[#3153]: https://github.com/bytedance/deer-flow/pull/3153
[#3174]: https://github.com/bytedance/deer-flow/pull/3174
[#3176]: https://github.com/bytedance/deer-flow/pull/3176
[#3200]: https://github.com/bytedance/deer-flow/pull/3200
[#3228]: https://github.com/bytedance/deer-flow/pull/3228
[#3233]: https://github.com/bytedance/deer-flow/pull/3233
[#3241]: https://github.com/bytedance/deer-flow/pull/3241
[#3252]: https://github.com/bytedance/deer-flow/pull/3252
[#3283]: https://github.com/bytedance/deer-flow/pull/3283
[#3284]: https://github.com/bytedance/deer-flow/pull/3284
[#3301]: https://github.com/bytedance/deer-flow/pull/3301
[#3307]: https://github.com/bytedance/deer-flow/pull/3307
[#3393]: https://github.com/bytedance/deer-flow/pull/3393
[#3413]: https://github.com/bytedance/deer-flow/pull/3413
[#3425]: https://github.com/bytedance/deer-flow/pull/3425
[#3453]: https://github.com/bytedance/deer-flow/pull/3453
[#3457]: https://github.com/bytedance/deer-flow/pull/3457
[#3461]: https://github.com/bytedance/deer-flow/pull/3461
[#3466]: https://github.com/bytedance/deer-flow/pull/3466
[#3475]: https://github.com/bytedance/deer-flow/pull/3475
[#3487]: https://github.com/bytedance/deer-flow/pull/3487
[#3499]: https://github.com/bytedance/deer-flow/pull/3499
[#3508]: https://github.com/bytedance/deer-flow/pull/3508
[#3512]: https://github.com/bytedance/deer-flow/pull/3512
[#3518]: https://github.com/bytedance/deer-flow/pull/3518
[#3528]: https://github.com/bytedance/deer-flow/pull/3528
[#3531]: https://github.com/bytedance/deer-flow/pull/3531
[#3559]: https://github.com/bytedance/deer-flow/pull/3559
[#3570]: https://github.com/bytedance/deer-flow/pull/3570