AIWatch.

What's Changed

• fix: preserve completed tool guardrail results by @seratch in #4180
• fix: redact invalid tool argument errors by @seratch in #4182
• fix: defer non-stream session saves until output guardrails by @seratch in #4184
• fix: honor resolved status before policy checks by @seratch in #4183
• fix: cancel sibling work after concurrent failures by @seratch in #4185
• fix: surface non-streaming content-filter refusals by @seratch in #4188
• fix(mcp): derive streamable HTTP retry backoff from backoffs taken by @rxits in #4174
• fix(realtime): clean up failed connection attempts by @seratch in #4189
• fix(tracing): mark non-streaming agent span failures by @seratch in #4191
• fix(sandbox): enforce token output budgets by @cosin2077 in #3934
• fix(sandbox): single-flight cached dependency factories by @seratch in #4178
• fix(sessions): enforce closed state in MongoDBSession by @seratch in #4176
• fix(sessions): preserve repeated history provenance by @seratch in #4181
• fix(sessions): skip conversation creation on empty add_items by @seratch in #4190
• fix(sessions): reject reused branch IDs when creating a branch by @seratch in #4186
• fix(extensions): preserve streamed provider thinking blocks by @seratch in #4177

Documentation & Other Changes

• perf: speed up the test suite by @seratch in #4171
• test: make parallel guardrail overlap deterministic by @seratch in #4187
• test: make async tool and guardrail tests deterministic by @seratch in #4192
• test: make parent cancellation tests deterministic by @seratch in #4193
• Release 0.19.4 by @github-actions[bot] in #4194

New Contributors

• @rxits made their first contribution in #4174
• @cosin2077 made their first contribution in #3934

Full Changelog: v0.19.3...v0.19.4