Change behavior from silent clamping to returning an error when the
model requests a foreground timeout exceeding FOREGROUND_MAX_TIMEOUT.
This forces the model to use background=true for long-running commands
rather than silently changing its intent.
- Config default timeouts above the cap are NOT rejected (user's choice)
- Only explicit model-requested timeouts trigger rejection
- Added boundary test for timeout exactly at the limit
When the model calls terminal() in foreground mode without background=true
(e.g. to start a server), the tool call blocks until the command exits or
the timeout expires. Without an upper bound the model can request arbitrarily
high timeouts (the schema had minimum=1 but no maximum), blocking the entire
agent session for hours until the gateway idle watchdog kills it.
Changes:
- Add FOREGROUND_MAX_TIMEOUT (600s, configurable via
TERMINAL_MAX_FOREGROUND_TIMEOUT env var) that caps foreground timeout
- Clamp effective_timeout to the cap when background=false and timeout
exceeds the limit
- Include a timeout_note in the tool result when clamped, nudging the
model to use background=true for long-running processes
- Update schema description to show the max timeout value
- Remove dead clamping code in the background branch that could never
fire (max_timeout was set to effective_timeout, so timeout > max_timeout
was always false)
- Add 7 tests covering clamping, no-clamping, config-default-exceeds-cap
edge case, background bypass, default timeout, constant value, and
schema content
Self-review fixes:
- Fixed bug where timeout_note said 'Requested timeout Nones' when
clamping fired from config default exceeding cap (timeout param is
None). Now uses unclamped_timeout instead of the raw timeout param.
- Removed unused pytest import from test file
- Extracted test config dict into _make_env_config() helper
- Fixed tautological test_default_value assertion
- Added missing test for config default > cap with no model timeout
