teknium1
d10bb2ab6f
`scripts/run_tests.sh tests/<dir>/` is how a change gets its regression
coverage run, so a test filed under the wrong directory is a test nobody
runs when that code changes. Two kinds of drift had accumulated.
Parallel directories for one source package, folded into the mirror:
tests/acp -> tests/acp_adapter (its __init__/conftest move with it)
tests/cli -> tests/hermes_cli (prompt_toolkit fixture merged into
hermes_cli/conftest.py)
tests/run_agent -> tests/agent (backoff fixture becomes
agent/conftest.py)
tests/relay -> tests/gateway/relay
tests/state -> tests/hermes_state
246 loose files at tests/ root, routed by the package they import/patch:
hermes_cli, hermes_state, agent, gateway, tools, plugins, tui_gateway, cron.
Installer and desktop-update script tests go to tests/scripts/{install,
desktop_update}/. 43 tests of root-level modules (batch_runner, utils,
hermes_constants, packaging) stay at the root.
Filenames drop their issue numbers (95 files: test_89315_x.py -> test_x.py);
the number stays in the module docstring where it has context.
Collisions: test_cli_skin_integration.py existed in both tests/ and tests/cli
with different subsets — merged into one (10 tests, all kept);
run_agent/test_pre_compress_memory_context.py -> agent/..._handoff.py;
tests/test_account_usage.py -> agent/test_account_usage_fetch.py;
tests/test_web_server.py -> hermes_cli/test_web_server_ws_ping.py.
Deleted: test_minisweagent_path.py (empty since PR #2804),
test_model_picker_scroll.py (tested a private copy of the logic, imported
nothing), test_process_loop_event_loop_warning.py (asserted asyncio behaviour,
imported nothing from Hermes).
Repo-root path arithmetic (Path(__file__).parents[N], dirname chains) is
bumped for the 202 files that changed depth and verified by evaluating every
such expression against the new location. classify_changes' desktop-updater
lane prefix, tests-os.yml's ignore glob and every in-tree path comment follow
the moves. tests/test_tests_tree_layout.py keeps the tree from drifting back.
182 lines
5.0 KiB
Markdown
182 lines
5.0 KiB
Markdown
---
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sidebar_position: 2
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title: "ACP Internals"
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description: "How the ACP adapter works: lifecycle, sessions, event bridge, approvals, and tool rendering"
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---
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# ACP Internals
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The ACP adapter wraps Hermes' synchronous `AIAgent` in an async JSON-RPC stdio server.
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Key implementation files:
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- `acp_adapter/entry.py`
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- `acp_adapter/server.py`
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- `acp_adapter/session.py`
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- `acp_adapter/events.py`
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- `acp_adapter/permissions.py`
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- `acp_adapter/tools.py`
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- `acp_adapter/auth.py`
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## Boot flow
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```text
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hermes acp / hermes-acp / python -m acp_adapter
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-> acp_adapter.entry.main()
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-> parse --version / --check / --setup before server startup
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-> load ~/.hermes/.env
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-> configure stderr logging
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-> construct HermesACPAgent
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-> acp.run_agent(agent, use_unstable_protocol=True)
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```
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Stdout is reserved for ACP JSON-RPC transport. Human-readable logs go to stderr.
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## Major components
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### `HermesACPAgent`
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`acp_adapter/server.py` implements the ACP agent protocol.
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Responsibilities:
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- initialize / authenticate
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- new/load/resume/fork/list/cancel session methods
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- prompt execution
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- session model switching
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- wiring sync AIAgent callbacks into ACP async notifications
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### `SessionManager`
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`acp_adapter/session.py` tracks live ACP sessions.
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Each session stores:
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- `session_id`
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- `agent`
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- `cwd`
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- `model`
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- `history`
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- `cancel_event`
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The manager is thread-safe and supports:
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- create
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- get
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- remove
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- fork
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- list
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- cleanup
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- cwd updates
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### Event bridge
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`acp_adapter/events.py` converts AIAgent callbacks into ACP `session_update` events.
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Bridged callbacks:
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- `tool_progress_callback`
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- `thinking_callback` (currently set to `None` in the ACP bridge — reasoning is forwarded through `step_callback` instead)
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- `step_callback`
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Because `AIAgent` runs in a worker thread while ACP I/O lives on the main event loop, the bridge uses:
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```python
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asyncio.run_coroutine_threadsafe(...)
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```
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### Permission bridge
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`acp_adapter/permissions.py` adapts dangerous terminal approval prompts into ACP permission requests.
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Mapping:
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- `allow_once` -> Hermes `once`
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- `allow_always` -> Hermes `always`
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- reject options -> Hermes `deny`
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Timeouts and bridge failures deny by default.
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### Tool rendering helpers
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`acp_adapter/tools.py` maps Hermes tools to ACP tool kinds and builds editor-facing content.
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Examples:
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- `patch` / `write_file` -> file diffs
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- `terminal` -> shell command text
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- `read_file` / `search_files` -> text previews
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- large results -> truncated text blocks for UI safety
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## Session lifecycle
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```text
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new_session(cwd)
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-> create SessionState
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-> create AIAgent(platform="acp", enabled_toolsets=["hermes-acp"])
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-> bind task_id/session_id to cwd override
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prompt(..., session_id)
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-> extract text from ACP content blocks
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-> reset cancel event
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-> install callbacks + approval bridge
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-> run AIAgent in ThreadPoolExecutor
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-> update session history
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-> emit final agent message chunk
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```
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### Cancelation
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`cancel(session_id)`:
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- sets the session cancel event
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- calls `agent.interrupt()` when available
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- causes the prompt response to return `stop_reason="cancelled"`
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### Forking
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`fork_session()` deep-copies message history into a new live session, preserving conversation state while giving the fork its own session ID and cwd.
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## Provider/auth behavior
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ACP does not implement its own auth store.
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Instead it reuses Hermes' runtime resolver:
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- `acp_adapter/auth.py`
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- `hermes_cli/runtime_provider.py`
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So ACP advertises and uses the currently configured Hermes provider/credentials. It also always advertises a terminal setup auth method (`hermes-setup`, args `--setup`) so first-run ACP clients can open Hermes' interactive model/provider configuration before starting a normal ACP session.
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## Working directory binding
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ACP sessions carry an editor cwd.
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The session manager binds that cwd to the ACP session ID via task-scoped terminal/file overrides, so file and terminal tools operate relative to the editor workspace.
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## Duplicate same-name tool calls
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The event bridge tracks tool IDs FIFO per tool name, not just one ID per name. This is important for:
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- parallel same-name calls
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- repeated same-name calls in one step
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Without FIFO queues, completion events would attach to the wrong tool invocation.
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## Approval callback restoration
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ACP temporarily installs an approval callback on the terminal tool during prompt execution, then restores the previous callback afterward. This avoids leaving ACP session-specific approval handlers installed globally forever.
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## Current limitations
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- ACP sessions are persisted to the shared `~/.hermes/state.db` (SessionDB) and transparently restored across process restarts; they appear in `session_search`
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- non-text prompt blocks are currently ignored for request text extraction
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- editor-specific UX varies by ACP client implementation
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## Related files
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- `tests/acp_adapter/` — ACP test suite
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- `toolsets.py` — `hermes-acp` toolset definition
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- `hermes_cli/main.py` — `hermes acp` CLI subcommand
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- `pyproject.toml` — `[acp]` optional dependency + `hermes-acp` script
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