PR Summary

Medium Risk
Changes message/tool routing behavior: some sessions_spawn calls will now hard-fail on previously ignored params, and Telegram DMs for non-default accounts may be dropped unless explicitly bound.

Overview
Prevents sessions_spawn from being used as an implicit channel-delivery mechanism by rejecting routing/delivery-like params (e.g. target, channel, to, threadId, replyTo, transport) with a ToolInputError, and adds regression tests + docs guidance to use message/sessions_send instead.

Hardens Telegram multi-account isolation by dropping inbound messages when a non-default account’s route resolution falls back to matchedBy="default", avoiding cross-account DM/session contamination; includes targeted test coverage and changelog entries.

^{Written by Cursor Bugbot for commit 14f324c. This will update automatically on new commits. Configure here.}

Greptile Summary

This PR hardens two security and correctness issues:

• sessions_spawn parameter validation: Added explicit rejection of unsupported delivery/routing parameters (target, channel, to, threadId, replyTo, transport) with clear error messages directing users to use message or sessions_send tools instead. This prevents silent failures where delivery intent could leak to parent conversations.

• Telegram multi-account isolation: Implemented fail-closed behavior for non-default Telegram accounts when route resolution falls back to matchedBy=default. This prevents cross-account DM/session contamination by requiring explicit account bindings for named accounts.

Both changes include comprehensive test coverage and documentation updates. The implementation correctly validates parameters before processing and applies the account isolation check early in the message handling pipeline.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• Score reflects well-tested security hardening with clear architectural improvements. Both changes include targeted regression tests, proper error handling, and documentation. The changes are breaking but necessary for correctness - preventing silent failures in sessions_spawn and cross-account contamination in Telegram routing.
• No files require special attention

_{Last reviewed commit: 14f324c}