feat(mcp): adopt mcp__server__tool naming convention (port from opencode#33533) - #52750
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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
…nvention TestMcpParallelToolBatch seeded provenance under old-style mcp_<server>_<tool> names, which no longer pass the is_mcp_tool_parallel_safe() prefix gate after the naming change.
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Models (notably GLM) sometimes emit MCP tool names without the full mcp__<server>__ prefix — e.g. list_memory_projects instead of mcp__basic_memory__list_memory_projects. The existing repair pipeline (case-folding, CamelCase, suffix stripping, fuzzy match at 0.7 cutoff) cannot map the bare suffix back to the full prefixed name, so the call fails with "Unknown tool" and the agent burns 3 retries before aborting with "Model generated invalid tool call". Add two repair paths in repair_tool_call() before the fuzzy-match fallback: 1. Bare suffix (no __ in emitted name): scan registered mcp__ tools and match on the tool-suffix portion. Skip when ambiguous (multiple servers expose the same suffix) to avoid non-deterministic routing. 2. Partial prefix (__ in emitted name but missing mcp__): prepend mcp__ and check for an exact match. The mcp__server__tool naming convention was introduced in NousResearch#52750 (merged 2026-07-05). Prior PRs NousResearch#21696, NousResearch#37100, NousResearch#33359 target the old single-underscore mcp_ format and do not apply to the new convention. 9 new tests in TestMcpPrefixRepair covering both cases, ambiguity guard, and non-MCP tool passthrough. All 38 tests in test_repair_tool_call_name.py pass.
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Models (notably GLM) sometimes emit MCP tool names without the full mcp__<server>__ prefix — e.g. list_memory_projects instead of mcp__basic_memory__list_memory_projects. The existing repair pipeline (case-folding, CamelCase, suffix stripping, fuzzy match at 0.7 cutoff) cannot map the bare suffix back to the full prefixed name, so the call fails with "Unknown tool" and the agent burns 3 retries before aborting with "Model generated invalid tool call". Add two repair paths in repair_tool_call() before the fuzzy-match fallback: 1. Bare suffix (no __ in emitted name): scan registered mcp__ tools and match on the tool-suffix portion. Skip when ambiguous (multiple servers expose the same suffix) to avoid non-deterministic routing. 2. Partial prefix (__ in emitted name but missing mcp__): prepend mcp__ and check for an exact match. The mcp__server__tool naming convention was introduced in NousResearch#52750 (merged 2026-07-05). Prior PRs NousResearch#21696, NousResearch#37100, NousResearch#33359 target the old single-underscore mcp_ format and do not apply to the new convention. 9 new tests in TestMcpPrefixRepair covering both cases, ambiguity guard, and non-MCP tool passthrough. All 38 tests in test_repair_tool_call_name.py pass.
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Summary
Native MCP tools now register as
mcp__<server>__<tool>(double-underscore delimiter), matching the convention used by Claude Code, Codex, and OpenCode. Previously Hermes usedmcp_<server>_<tool>, whose single-underscore boundary is ambiguous when a server or tool name contains underscores.Ported from anomalyco/opencode#33533.
Why
mcp_my_server_querycan't be reliably split into server vs tool.is_mcp_tool_parallel_safe()already documented this ("that string shape is ambiguous when server names contain underscores") and worked around it with a provenance side-map. Themcp__server__toolform makes the boundary explicit.mcp__prefix; aligning means the model recognizes MCP-sourced tools by name shape.agent/anthropic_adapter.py,_MCP_TOOL_PREFIX = "mcp__", [Bug]: Anthropic OAuth stripsmcp_prefix from Hermes-native MCP tool names, breaking registry lookup #25255) already rewrote native single-underscore names up tomcp__on the wire and reversed them on response. Native registration now producesmcp__directly, so that promotion is a no-op for native tools — while the legacy single→double promotion is retained for tool names replayed from older sessions.Changes
tools/mcp_tool.py: addMCP_TOOL_NAME_PREFIX+mcp_prefixed_tool_name()helper; route_convert_mcp_schema, the resources/prompts utility schemas, the refresh stale-name set, and theis_mcp_tool_parallel_safeprefix gate through it.agent/transports/codex_event_projector.py: mirror the convention in the deterministiccall_idinput for MCP server-executed tool calls (Codex Responses streaming), keeping it consistent with registration names.tests/: update produced-name assertions intest_mcp_tool.py,test_mcp_dynamic_discovery.py,test_toolsets.pyto the new convention.Adaptation notes (vs. the OpenCode PR)
OpenCode's change was a one-line string-template swap (
sanitize(server) + "_" + sanitize(tool)→"mcp__" + ... + "__" + ...). Hermes had the same name constructed in several places plus twostartswith("mcp_")parse sites and a deterministic-call-id derivation, so this introduces a singlemcp_prefixed_tool_name()helper and routes every site through it rather than scattering literals. The Anthropic-OAuth interplay (which has no analog in OpenCode) is left intact — it already handles both forms and now does less work.Backward-compat: tool names are produced fresh per process; this only affects new sessions (no mid-conversation cache invalidation). MCP
tools.include/excludeconfig references the bare tool name, not the prefixed name, so existing configs are unaffected. Themcp-<server>toolset alias (hyphen) is unrelated and unchanged.Validation
test_mcp_tool.pytest_mcp_dynamic_discovery.pytest_toolsets.pytest_anthropic_mcp_prefix_strip.py(OAuth interplay)test_codex_event_projector.pyInfographic