Port from anomalyco/opencode#33533. Native MCP tools now register as
mcp__<server>__<tool> (double-underscore delimiter) instead of
mcp_<server>_<tool>, aligning with the convention used by Claude Code,
Codex, and OpenCode.
The double-underscore delimiter disambiguates the server/tool boundary
even when either component contains underscores (the single-underscore
form was ambiguous, which is why is_mcp_tool_parallel_safe already had to
track provenance in a side-map). It also unifies native registration with
the Anthropic-OAuth wire form (_MCP_TOOL_PREFIX = 'mcp__'), so the
single->double promotion that path performed is now a no-op for native
tools while still handling legacy replayed names.
- tools/mcp_tool.py: add MCP_TOOL_NAME_PREFIX + mcp_prefixed_tool_name()
helper; route _convert_mcp_schema, utility schemas, refresh stale-set,
and the parallel-safe prefix gate through it
- agent/transports/codex_event_projector.py: mirror convention in the
deterministic call_id input for MCP server-executed tool calls
- tests: update produced-name assertions to the new convention
e01f58ff1f