EXPERIMENT (NOT FOR PRODUCTION YET)
Changes:
- KEEPALIVE_INTERVAL_SECONDS reduced from 20s to 5s
- Keepalive messages now show progress bar with dots: ●●●●○○○○○○
- Show elapsed time, total wait, and remaining seconds
- Example: ⏳ Waiting for instructions... ●●●●○○○○○○ 20s / 50s (agent=copilot, 30s remaining)
Goal: Test if more frequent progress updates provide better UX and prevent
perceived freezing during the 50s wait. No functional change - the
60s client timeout limit remains the binding constraint.
When the tool is waiting for an instruction, send ctx.info() log
notifications to the client every KEEPALIVE_INTERVAL_SECONDS (default 20).
Purpose
-------
These notifications write bytes to the SSE stream, resetting any
transport-level HTTP read timeout on the client side (e.g. httpx
Timeout(read=N)). This prevents premature connection drops when
wait periods exceed the client's inactivity window.
Caveat
------
Application-level wall-clock timers (anyio.fail_after / JS SDK
equivalents) are NOT affected by SSE events -- they count from
request start regardless. This is confirmed by experiments in
tests/test_keepalive.py and tests/run_keepalive_experiments.py.
Experiment results (summarised in tests/run_keepalive_experiments.py)
----------------------------------------------------------------------
- Exp 1: anyio.fail_after(5s) fires at 5.98s with NO keepalives.
- Exp 2: anyio.fail_after(10s) fires at 10.90s WITH keepalives every 2s.
Keepalives have ZERO effect on app-level timers.
- Exp 3b: httpx read=8s, keepalive=2s -> SUCCESS at 51s.
Keepalives DO prevent transport-level read timeouts.
The Copilot extension 60s limit is almost certainly application-level
(hardcoded wall-clock), so default_wait_seconds=50 remains the correct
mitigation (returns before the 60s deadline). The keepalives provide
defence-in-depth against any proxy/NAT inactivity drops.
Wait time is now fully server-controlled via default_wait_seconds setting.
Agents can no longer request a different wait duration - only the user
controls this via the web UI.
- Remove wait_seconds param from get_user_request signature
- Simplify actual_wait to min(cfg.default_wait_seconds, MAX_WAIT)
- Update Settings panel label from 'Min Wait' to 'Wait (sec)'
- Update hint text to explain server-only control
- Update README: input schema, behavior rules, settings description, changelog
