The double-underscore prefix swap fixed bare native tools but SKIPPED tools
already named mcp_<server>_<tool> (real MCP servers, e.g. mcp_linear_get_issue):
they went on the OAuth wire single-underscore and still tripped Anthropic's
third-party billing classifier -> HTTP 400 'extra usage, not plan limits'.
Verified empirically against a live Max subscription: a single mcp_ tool flips
the whole request to the extra-usage lane; mcp__ is accepted.
- build_anthropic_kwargs: promote ANY leading single-underscore mcp_ to mcp__
(bare names -> mcp__name; mcp_<server>_<tool> -> mcp__<server>_<tool>),
never double-prefixing an already-mcp__ name. Same for tool_use blocks in
history.
- normalize_response: reverse the mcp__ wire name back to whichever original
the registry knows — the single-underscore mcp_<server>_<tool> form for MCP
server tools, or the bare name for native tools — preferring a name that
already resolves natively.
- Tests rewritten to assert the invariant: ZERO single-underscore mcp_ names
reach the OAuth wire, and the mcp__ round-trip resolves back to the
registered name for both native and MCP-server tools.
Builds on liuhao1024's mcp__ prefix commit (cherry-picked). Closes the
MCP-server gap that left any session with an MCP server configured still
billing to extra usage.
Anthropic's Claude-Code request classifier treats tool names with a
single-underscore `mcp_<x>` prefix as non-Claude-Code / third-party,
routing the request to extra-usage billing (HTTP 400). Real Claude Code
uses double underscores: `mcp__<server>__<tool>`.
Change the tool-name prefix from `mcp_` to `mcp__` in both the outgoing
path (build_anthropic_kwargs) and the incoming path
(normalize_response). Update the skip-guard to check for both `mcp_`
and `mcp__` prefixes so native MCP server tools (which use the legacy
single-underscore format) are not double-prefixed.
Fixes#46675
Remove unused imports (F401) and duplicate/shadowed import
redefinitions (F811) across the codebase using ruff's safe
autofixes. No behavioral changes -- imports only.
- ~1400 safe autofixes applied across 644 files (net -1072 lines)
- __init__.py re-exports preserved (excluded from F401 removal so
public re-export surfaces stay intact)
- Re-exports that are imported or monkeypatched by tests but look
unused in their defining module are kept with explicit # noqa:
F401 (gateway/run.py load_dotenv; run_agent re-exports from
agent.message_sanitization, agent.context_compressor,
agent.retry_utils, agent.prompt_builder, agent.process_bootstrap,
agent.codex_responses_adapter)
- Unsafe F841 (unused-variable) fixes deliberately skipped -- those
can change behavior when the RHS has side effects
- ruff lints remain disabled in pyproject.toml (only PLW1514 is
selected); this is a one-time cleanup, not a config change
Verification:
- python -m compileall: clean
- pytest --collect-only: all 27161 tests collect (zero import errors)
- core entry points import clean (run_agent, model_tools, cli,
toolsets, hermes_state, batch_runner, gateway)
- static scan: every name any test imports directly from an edited
module still resolves
Companion to the GH-25255 incoming-strip fix from @hayka-pacha. Without
this, build_anthropic_kwargs unconditionally added 'mcp_' to every tool
name in step 3, so a native MCP server tool registered as
'mcp_composio_X' was sent as 'mcp_mcp_composio_X' on the wire. The
incoming strip only removes ONE prefix, which still worked on first
call, but on subsequent calls the model pattern-matched the
single-prefixed form from message history and produced names that
stripped to 'composio_X' — registry miss, dispatch fail.
The history-rewrite block (#4) already has this guard. Apply the same
guard to the schema-rewrite block (#3) so round-trip is symmetric.
Added 4 outgoing-side tests. Existing 7 incoming-side tests still pass.
Author map: hayka-pacha added for PR #25270 salvage attribution.
Refs GH-25255.
When strip_tool_prefix=True (Anthropic OAuth path), normalize_response
unconditionally stripped the mcp_ prefix from ALL tool names starting
with mcp_. This broke Hermes-native MCP server tools (registered under
their full mcp_<server>_<tool> name in the registry) because the stripped
name doesn't match any registry entry.
Fix: check the tool registry before stripping. Only strip when:
- The stripped name EXISTS in the registry (OAuth-injected tool)
- The full name does NOT exist in the registry
This preserves backward compatibility for OAuth-injected tools while
protecting native MCP server tools from incorrect prefix removal.
7 new tests covering: OAuth strip, native preserve, no-flag, non-mcp,
unknown tools, mixed responses, and dual-registration edge case.
Signed-off-by: HKPA <hayka-pacha@users.noreply.github.com>
