Release 0.4.0: Async tools

Highlights

• Introduced async tool execution support.
• Simplified public error handling by removing StructuredOutput.
• Added provider-specific max token handling in LLMCore.
• Improved tool error responses by preserving tool arguments on failure.

Breaking Changes

StructuredOutput removed from public API

StructuredOutput(value, error) is no longer used for non-streaming APIs.
Success now returns plain values, and failures raise ErrorPayload.

Affected API families include:

• LLM.chat*, LLM.tool_calls*, LLM.if_*, LLM.classify*, LLM.embed*
• Tape.chat*, Tape.tool_calls*
• ToolExecutor.execute(...) now raises ErrorPayload for validation/input/tool lookup failures

Also removed/simplified:

• ContextSelection removed (read_messages(...) returns list[dict[str, Any]])
• QueryResult removed (TapeQuery.all() returns list[TapeEntry])

Migration pattern:

• Replace .value / .error checks with try/except ErrorPayload.
• Search old usage quickly with:

rg -n "StructuredOutput|\\.value\\b|\\.error\\b" src tests

For detailed migration examples, see docs/guides/breaking-changes.md.

Features

• feat: implement async tool execution (86a5f43)

  • Added async execution path for tool calls.
  • Updated chat client and tool executor integration.
  • Expanded contract and UX test coverage around async behavior.

• feat: add provider-specific max tokens handling in LLMCore (a79be07)

  • LLMCore now applies max token behavior with provider-specific handling.

Fixes

• fix: return tool arguments on error in tool response handling (279a36e)
  • Tool execution error responses now preserve original tool arguments for better debugging and recovery.

Refactors and Tooling

• refactor: Refactor error handling and remove StructuredOutput (025b045)
  • Aligned client/core error semantics to Python-style exceptions.
  • Updated tape query/context/session return types.
  • Refreshed tests for new behavior.
• CI/dev tooling updates:
  • Switched workflow hooks from pre-commit to prek.
  • Updated related config/docs and lockfile.

Diff Summary

From 0.3.2 to 0.4.0:

• 5 commits
• 25 files changed
• 998 insertions, 696 deletions

Recommended Upgrade Checklist

• Update call sites that rely on .value / .error.
• Add/adjust exception handling for ErrorPayload.
• Re-run test suites covering chat/tool-call/tape flows.
• Validate provider-specific token limits in your production configs.