v0.4.0 (2026-06-17)

What's Changed

• feat: add FileSystem and Shell capabilities by @strawgate in #260
• feat(logfire): add ManagedPrompt capability by @dmontagu in #257
• feat: add Planning capability with cache-safe plan reminders (experimental) by @strawgate in #266
• feat: add SubAgents capability for task delegation (experimental) by @strawgate in #267
• Add StepPersistence capability for step-event durability across delegates (experimental) by @dsfaccini in #251
• Add experimental compaction menu: SummarizingCompaction, ClearToolResults, DeduplicateFileReads, TieredCompaction by @DouweM in
  #191
• feat(compaction): add ClampOversizedMessages for runaway generations (experimental) by @dsfaccini in #286
• feat(experimental): OverflowingToolOutput capability for oversized tool returns by @dsfaccini in #290
• feat(subagents): per-delegate run controls (usage limits, timeout, call budget, soft-failure) (experimental) by @dsfaccini in #283
• feat(shell): control subprocess environment to stop secret inheritance by @dsfaccini in #284
• Add host-backed OS and filesystem access to CodeMode sandbox by @adtyavrdhn in #262
• Add CodeMode dynamic_catalog flag for cache-stable tool disclosure by @DouweM in #243
• ci: add pydantic-ai v2 beta early-warning job and make code_mode v1/v2 compatible by @adtyavrdhn in #291

New Contributors

• @strawgate made their first contribution in #260
• @gblackadder made their first contribution in #228

Full Changelog: v0.3.0...v0.4.0