app/agents/shared/ is a sibling of anonymous_chat/podcaster/multi_agent_chat/
video_presentation, so it should only hold code shared across 2+ of those
agents. In practice podcaster and video_presentation import nothing from it,
and anonymous_chat needs only context + compaction + retry_after + web_search.
Everything else was multi_agent_chat-only (the boundary just passes through).
Move the multi_agent_chat-only cluster into multi_agent_chat/shared/ (files
moved verbatim via git rename; ~116 import sites rewritten):
errors, feature_flags, filesystem_selection, path_resolver, prompt_caching,
sandbox, llm_config, mention_resolver
middleware/busy_mutex, middleware/kb_persistence
busy_mutex/llm_config/mention_resolver are boundary-only but import the moved
modules, so they were folded in to avoid a backwards shared -> multi_agent_chat
dependency. main_agent builders now import the impls directly; the shared
middleware barrel keeps only the genuinely-shared compaction + retry_after.
Also delete the dead leftover shared/plugins and shared/skills dirs (live
copies already live under main_agent/).
Remaining in app/agents/shared/: context, system_prompt(+prompts), checkpointer,
middleware/{compaction,retry_after,dedup_tool_calls}, tools/. checkpointer and
system_prompt are boundary-only infra pending a dedicated home decision.
The concrete filesystem backends are consumed only by the MAC filesystem
layer (tools, path-resolution middleware, the resolver, skills backend) and
tests -- no external app code. Group them next to the filesystem middleware
they serve:
- filesystem_backends.py -> filesystem/backends/resolver.py
- middleware/kb_postgres_backend.py -> filesystem/backends/kb_postgres.py
- middleware/local_folder_backend.py -> filesystem/backends/local_folder.py
- middleware/multi_root_local_folder_backend.py -> .../multi_root_local_folder.py
- document_xml.py -> filesystem/backends/document_xml.py
Repoint all 21 importers. No behavior change; import-all + filesystem
backend/path-resolution/knowledge-search unit tests stay green (478).
Eliminate the top-level multi_agent_chat/middleware/ package so each slice
owns its middleware (vertical-slice colocation):
- middleware/shared/ -> shared/middleware/ (cross-slice middleware)
- middleware/subagent/ -> subagents/shared/middleware/ (subagent stack)
- main_agent/middleware/ already colocated in Slice A
The moved shared/ subtree is internally consistent (all relative imports
stay within it), so only external absolute refs were rewritten. The
subagent stack's ..shared.* relatives were promoted to absolute paths to
the new shared/middleware/ location.
multi_agent_chat/ root is now: main_agent/, shared/, subagents/.
Verified: 2430 unit tests pass, 1 skipped (baseline unchanged).
The single-agent-era filesystem middleware (app/agents/shared/middleware/
filesystem.py, ~2000 lines) was never instantiated in production, yet three
unit suites validated it — an illusory guardrail while the live decomposed
middleware (multi_agent_chat/middleware/shared/filesystem) was unguarded.
Close the gap before reorganizing the agents module:
- Add 14 integration tests driving live B's tools in desktop mode (real
on-disk effects) and cloud mode (in-state staging, namespace policy).
- Port all high-value dead-twin assertions onto the live path: cloud rm/rmdir
staging + guard rails, KBPostgresBackend delete-view filter, mode-scoped
system prompt, cwd/relative/namespace resolution, multi-root mount
normalization.
- Delete dead twin filesystem.py, drop its __init__ re-export, and retire its
3 dead-twin tests.
Verified: test_import_all + middleware unit + FS integration all green.
