Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
ToolsArea: what it touches
Internal ChangesKind: in v2.1.257,
Internal ChangesSection of the release
New internal classification logic sorts 400 errors from beta tool-use blocks into specific reasons: header_rejected, block_type_unknown, after_paused_turn, model_unsupported, too_many_definitions, pfc_only, unknown_tool_reference, or other. This applies when a tool_addition or tool_removal request is rejected, likely feeding retry and telemetry logic for beta feature flags.
Read from
Names in the bundleheader_rejectedmodel_unsupportedtoo_many_definitions
