Release v0.31.0 (2026-09-11) · pydantic/pydantic-ai-harness

What's Changed

Add eager streamed execution to CodeMode by @mpfaffenberger in #746
Fix PlanStore get_items and set_items docstrings by @mpfaffenberger in #843
Add tool_return_max_chars to SummarizingCompaction by @mpfaffenberger in #842
Drop the unfulfilled 0.28.0 removal date from SpendStore deprecations by @mpfaffenberger in #841
Document the escaped-keys marker format in step_persistence docs by @mpfaffenberger in #840
Add an async and concurrency guide to agent_docs, ported from core by @mpfaffenberger in #835
Add optional tail-line retention to Truncate by @Quiyyy in #836
Anchor Planning cache breakpoint on the last durable user content by @pydanty in #833
Make FileSystem content hashes agree across read_file, write_file, and edit_file by @mpfaffenberger in #847
Correct for_run()-built approval-required tool calls to pending in ACP by @mpfaffenberger in #849
Stop SnapshotHistorySource.run_history duplicating messages with serializing stores by @mpfaffenberger in #848
Floor on released pydantic-ai 2.40.0 by @mpfaffenberger in #851
Emit DelegationStartEvent and DelegationEndEvent from SubAgents by @mpfaffenberger in #855
Fix the aws-lambda docs install line, which named a bedrock extra that does not exist by @mpfaffenberger in #854
Offer pip and uv installation commands throughout the Harness docs by @mpfaffenberger in #858
Give the CodeMode sandbox the value shape its own stubs declare by @bohdanhr in #681

Full Changelog: v0.30.0...v0.31.0