{"args":["Arguments passed to the tool · an object whose shape is the TOOL's own schema, not the language's. Each builtin and each MCP tool declares its own (spec/02-verbs.md §invoke) · `\u0024{{ }}` may appear in any leaf value."]}

the language

args

Arguments passed to the tool · an object whose shape is the TOOL's own schema, not the language's. Each builtin and each MCP tool declares its own (spec/02-verbs.md §invoke) · `${{ }}` may appear in any leaf value. One of 62 words the served contract declares, projected from workflow.schema.json, the same file your editor validates against.

1surfaceinvoke
optionaleverywherea choice, never a miss
objecttypethe declared shape
10skeletonscarry this key

the contract

1 declaration

Descriptions are the schema's own; the deeper invariants (value languages and regexes) ride the same projection. A miss is a nika check finding before anything runs.

invoke: objectArguments passed to the tool · an object whose shape is the TOOL's own schema, not the language's. Each builtin and each MCP tool declares its own (spec/02-verbs.md §invoke) · `${{ }}` may appear in any leaf value.inside invoke:

in a real file

from the chain skeleton

chain.nika.yaml

49  gather:50    ◆invoke:                         # SLOT: the fact source · nika:read / nika:fetch / exec51      tool: "nika:read"52      args: { path: "${{ const.source }}" }53    on_error:54      # Offline rehearsal. A freshly scaffolded directory has no README, and a55      # skeleton that dies on its first run teaches nothing — so a not-found56      # recovers into a literal standing in for the real document. `on_codes:`57      # keeps that narrow: ONLY not-found is forgiven, a permission error58      # still fails loudly. Delete this block once the source really exists.59      # In an EMPTY directory check prints one [inputs] hint that this read60      # would fail — the run does not: this recover carries it (measured ·61      # rc=0 · « 1 recovered »). The hint retires once your source exists.62      on_codes: [NIKA-BUILTIN-READ-001]63      recover: "REHEARSAL · no source document here yet."

a verbatim slice, real line numbers from chain.nika.yaml, conformance-gated upstream on every spec push. open the full skeleton →

cross-references

skeletons that carry it

where it lives

accepted by

invoke

[]

defined by

02-verbs

the block it lives in

invoke: inside invoke:

The whole grammar in one place: the four verbs · the standard library · the spec. Try it in the playground. Read the reference →