* .NET: Bound the tool-approval auto-approval loop (#7472)
`ToolApprovalAgent` re-invoked the inner agent from two unbounded `while (true)`
loops whenever every surfaced approval request was auto-approved. Each pass is a
fresh `InnerAgent.RunAsync` / `RunStreamingAsync` call, so a per-request cap such
as `FunctionInvokingChatClient.MaximumIterationsPerRequest` restarts every time
and cannot bound the chain. Under `AllToolsAutoApprovalRule` a model that keeps
requesting an auto-approved tool therefore drives billable model calls
indefinitely; the reporter measured 100M+ tokens over three days.
Adds `ToolApprovalAgentOptions.MaxAutoApprovalIterations` (default
`ToolApprovalAgent.DefaultMaxAutoApprovalIterations`, 10) and bounds both loops.
Naming, default and `Throw.IfLessThan` validation follow the existing
`LoopAgent.DefaultMaxIterations` / `LoopAgentOptions.MaxIterations` convention in
this assembly.
On reaching the cap the agent takes one final inner turn without auto-approving
again, so a remaining approval request is surfaced to the caller to decide.
Returning early instead would hand back an empty response, because
`ProcessAndQueueOutboundApprovalRequestsAsync` strips every approval request once
they are all auto-approved -- the case the loop exists to avoid. This mirrors the
Python behaviour, which logs and issues one final request with tools disabled
once its iteration budget is spent (`_tools.py`).
Python is not affected: it caps at `DEFAULT_MAX_ITERATIONS` (40) and persists
`attempt_count` in the budget state across approval resumes, so a resumed run
continues the count rather than restarting it.
Tests: the runaway is reproduced on both the streaming and non-streaming paths
with an inner agent that never stops requesting an auto-approved tool. Inner
invocations equal the cap plus the final turn, and scale with the configured cap,
so the assertions fail if the bound is removed.
No sample changes: with the loop bounded, Agent_Step01, Agent_Step06,
Agent_Step07 and Hosted-AgentSkills are safe as written.
* .NET: Add Arrange/Act/Assert comments to the cap constructor test
Matches the test convention documented in dotnet/AGENTS.md and used by the
surrounding tests in this file.
* Increase default max auto approval iterations to 40
* Apply suggestion from @westey-m
Co-authored-by: westey <164392973+westey-m@users.noreply.github.com>
* Update comments in ToolApprovalAgent.cs
---------
Co-authored-by: westey <164392973+westey-m@users.noreply.github.com>
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