MCP tools whose input schemas use top-level anyOf, oneOf, or allOf can now be normalized into a flat object schema, making them usable in Claude Code without being dropped.
- Controlled by the
tengu_mcp_normalize_root_combinatorsfeature flag. Set to["*"]for all MCP servers, or a list of hostnames to target specific ones. Hostname entries support subdomain matching:"example.com"also matchesapi.example.com. - Only URL-based MCP servers (those with a
urlproperty) are eligible. stdio and sdk-type servers have nourland are never normalized regardless of flag value. - The injected note in the tool description differs by combinator type:
allOfonly:"Input constraint: all listed parameters apply together (flattened from a JSON Schema allOf)."oneOf:"Input constraint: Provide parameters for exactly one of: (param_a, param_b) or (param_c)."anyOf:"Input constraint: Provide parameters for at least one of: (param_a, param_b) or (param_c)."- If parameter groups cannot be extracted from the schema branches, the note falls back to:
"Input constraint: Provide parameters for exactly one of the documented parameter groups (flattened from a JSON Schema oneOf)." - Only property names matching
/^[a-zA-Z0-9_.-]{1,64}$/are included in the flattened schema; others are silently excluded. - Top-level schema fields preserved through normalization:
$defs,definitions,$schema,additionalProperties,description,title. - If normalization fails for any reason, the tool is dropped with a logged reason (e.g.,
"input schema has top-level anyOf that is not an array") rather than silently accepted with a broken schema.
Schema normalization (search for "Input constraint: all listed parameters apply together", "Provide parameters for exactly one of", "Provide parameters for at least one of", Mxp, tengu_mcp_normalize_root_combinators)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
tengu_mcp_normalize_root_combinators Not enough to sayNothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.
This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.195: not a boolean we can read
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Read once, for one account on one subscription tier, against v2.1.195. It isn't a statement about your account. What a flag value here can and cannot tell you
A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
A reading is one sample. Claude Code evaluates its flags remotely, so no client sees the targeting rule behind a value and this says nothing about your account.
New in this build: tengu_mcp_normalize_root_combinators