refactor(error): rename taxonomy and translators for clearer layering

src/opencode_a2a/execution/executor.py

@@ -72,7 +72,7 @@
     _TTLCache,
 )
 from .tool_error_mapping import build_tool_error, map_a2a_tool_exception
-from .upstream_errors import (
+from .upstream_error_translator import (
     _await_stream_terminal_signal,
     _extract_upstream_error_detail,
     _format_inband_upstream_error,

src/opencode_a2a/execution/stream_events.py

@@ -8,7 +8,7 @@
 from a2a.types import TaskState
 
 from .stream_state import BlockType
-from .upstream_errors import (
+from .upstream_error_translator import (
     _format_inband_upstream_error,
     _format_stream_terminal_error,
     _StreamTerminalSignal,

src/opencode_a2a/execution/stream_runtime.py

@@ -45,7 +45,7 @@
     _StreamOutputState,
     _StreamPartState,
 )
-from .upstream_errors import _StreamTerminalSignal
+from .upstream_error_translator import _StreamTerminalSignal
 
 logger = logging.getLogger("opencode_a2a.execution.executor")
 

src/opencode_a2a/execution/upstream_errors.py → src/opencode_a2a/execution/upstream_error_translator.py

@@ -7,13 +7,13 @@
 import httpx
 from a2a.types import TaskState
 
-from ..error_taxonomy import (
+from ..opencode_upstream_client import UpstreamContractError
+from ..upstream_taxonomy import (
     extract_upstream_error_detail as _extract_upstream_error_detail,
 )
-from ..error_taxonomy import (
+from ..upstream_taxonomy import (
     resolve_upstream_http_error_profile as _resolve_upstream_error_profile,
 )
-from ..opencode_upstream_client import UpstreamContractError
 
 
 @dataclass(frozen=True)

src/opencode_a2a/jsonrpc/application.py

@@ -22,7 +22,7 @@
     SESSION_QUERY_ERROR_BUSINESS_CODES,
 )
 from ..opencode_upstream_client import OpencodeUpstreamClient, UpstreamContractError
-from .error_mapping import (
+from .error_responses import (
     interrupt_not_found_error,
     invalid_params_error,
     method_not_supported_error,

tests/jsonrpc/test_error_mapping.py → tests/jsonrpc/test_error_responses.py

@@ -2,7 +2,7 @@
 
 from a2a.types import InvalidParamsError
 
-from opencode_a2a.jsonrpc.error_mapping import (
+from opencode_a2a.jsonrpc.error_responses import (
     interrupt_not_found_error,
     invalid_params_error,
     method_not_supported_error,