Three independent paths bypassed the user's subagent caps:
1. TaskTool.#getSpawnSemaphore sized the spawn semaphore from
task.maxConcurrency only on first use and never re-read the setting,
so lowering the cap mid-session left every later spawn running
against the old ceiling. Resize the live semaphore against the
current setting on each acquire.
2. The task tool prompt threaded MAX_CONCURRENCY through to the
template but never rendered it. A model with task.maxConcurrency=1
could still emit oversized tasks[] batches that registered
immediately and piled up behind the semaphore. Render a 'Concurrency
cap' directive in task.md whenever the setting is bounded.
3. The eval agent() bridge's assertDepthAllowed gated only against
the hardcoded EVAL_AGENT_MAX_DEPTH=3 and ignored
task.maxRecursionDepth, so a user-tightened recursion limit
(0='None', 1='Single') still let cell-spawned subagents recurse
to depth 3. Mirror the task tool's canSpawnAtDepth gate, clamped
by the hard ceiling.
Fixes#3895
roboomp
1b9c6be129