The pane, in-app browser, and reaction tools were gated on HERMES_DESKTOP=1 —
an env var set only on backends Electron spawns itself (local and SSH). A
desktop client connected to a plain URL gateway or Hermes Cloud lost all six:
they were stripped from the schema before the model saw them, on the same
backend whose platform hint was telling it "you are chatting inside the Hermes
desktop app". open_preview, read_preview, read_terminal, close_terminal,
focus_pane, and react_to_message were all silently absent.
The client is not the host. Capability now resolves from the session's own
source, which session.create already carries:
- The six tools move into a `desktop_ui` toolset, off _HERMES_CORE_TOOLS so no
other platform pays their schema.
- _gui_surface_toolsets(platform) folds `desktop_ui` (and the existing
`project` tools) into the GUI gateway's resolution when the session's
platform is the desktop app — the same answer on every topology.
- check_fn drops the env probe. It kept the one thing that is genuinely a
per-process/user fact: react_to_message's display.message_reactions opt-in,
which the desktop mirrors onto whichever gateway it is connected to.
react_to_message was doubly broken: it read that toggle behind the env gate, so
even a local-backend user's Settings toggle could not reach a remote session.
The embedded terminal pane keeps working correctly the other way round: it runs
`hermes --tui` against a desktop-spawned backend, and a tui-sourced session
gets no GUI tools even though HERMES_DESKTOP=1 is set on that process.
The TUI banner reported fewer tools than the classic CLI for the same
config (e.g. 32 vs 38) when an MCP server connected slowly. Root cause:
the agent snapshots `agent.tools` once at build time and never re-reads
the registry. `_make_agent` briefly joins the background MCP discovery
thread (`wait_for_mcp_discovery`, ~0.75s) so fast servers land in that
snapshot, but a server slower than the bound — common for an HTTP MCP
server on first connect — lands *after* the agent is built. Its tools are
then absent from both the agent (uncallable until `/reload-mcp`) and the
banner for the whole session.
The classic CLI doesn't hit this because it re-derives
`get_tool_definitions()` at banner render time (which re-waits for
discovery), so it picks the late tools up.
Fix: after a fresh agent is built and its first `session.info` emitted,
if discovery is still in flight, schedule an off-critical-path daemon that
waits for it to finish, then rebuilds the tool snapshot and re-emits
`session.info` — the same rebuild `/reload-mcp` performs, but automatic.
Both the agent's callable tools and the banner count catch up.
Cache safety: the rebuild runs only while the session is still
pre-first-turn (`_user_turn_count`/`_api_call_count` both 0 → nothing
cached to invalidate). Once the user has sent a message we leave the
snapshot frozen rather than break the cached prompt prefix mid-conversation;
late tools then require an explicit `/reload-mcp` (user-consented), exactly
as today. No-op when discovery finished before the agent build, when the
join times out, when the registry was unchanged, or when the session was
swapped/closed while waiting.
Adds entry.mcp_discovery_in_flight() / join_mcp_discovery() accessors and
covers the matrix (added/none/post-turn/timeout/unchanged/replaced) with
unit tests.
Brooklyn Nicholson