PRAXO-CORE for V

V is a native Core implementation with source tag v/v0.1.1. It passes all eleven shared vector groups with V 0.5.2 and includes the native agent loop, context compaction, memory store, path policy, checkpoint allowlist, and tool-call parsing. Tool selection, PII redaction, structured output, and call limits are opt-in in the agent. Vector coverage does not establish full Core parity or production readiness.

The Core does not call Go or another language runtime. It has no provider adapter or plugin host; those remain outside the declared Core scope.

Build And Test

From the repository root with V and a C compiler on PATH:

python language/v/api-snapshot.py --check
v -cc tcc -gc none -o build/praxo-v-conformance language/v/conformance/run.v
./build/praxo-v-conformance
v -cc tcc -gc none -o build/praxo-v-tests language/v/tests/run.v
./build/praxo-v-tests

On Windows use build\praxo-v-conformance.exe and build\praxo-v-tests.exe. The -path flag is not needed: the compiler resolves import praxo from the language tree.

The complete local environment procedure, including manual V installation, is in SETUP.md.

API

import praxo

call := praxo.parse_tool_call('<tool_call name="echo">{"text":"hi"}</tool_call>') or {
    panic(err)
}
assert call.name == 'echo'

schema := praxo.parse_json('{"type":"string","pattern":"^a+$"}') or { panic(err) }
assert praxo.validate_schema(schema, praxo.parse_json('"aaa"') or { panic(err) }).len == 0

Public declarations are inventoried in api/0.1.1.txt.

Supply a model callback to receive each request and return a response or an error. The callback can inspect the conversation and tool results on each step; callback-backed models also work with fallback_model.

Set options.tool_selection = praxo.tool_selection(['echo']) to advertise and allow only the named tools. An empty selection denies all tools. Without a selection, all configured tools remain available. A request for an unselected tool fails with AGENT_TOOL_NOT_SELECTED before the tool is invoked.

Set options.pii_redaction = true to redact the existing email, SSN, credit-card, and US-style phone patterns in model-bound message content and text blocks, and in tool results recursively. This does not redact tool arguments, events, final output, block image/data fields, or arbitrary PII; it is not a complete privacy boundary. The original session messages are not modified.

Set options.structured_output = praxo.structured_output(schema, max_repairs, repairer) to validate the final output with the existing schema helper. A successful repair becomes the output; invalid output fails with AGENT_STRUCTURED_OUTPUT. Set options.model_call_limit and options.tool_call_limit to positive values to bound calls per run. Nonpositive values are unlimited. The next invocation is blocked with AGENT_MODEL_CALL_LIMIT or AGENT_TOOL_CALL_LIMIT; counters are independent for each run. All these options are disabled by default.

fn generate(req praxo.Request) !praxo.Response {
    return praxo.response(praxo.message_assistant('Hello', []praxo.ToolCall{}), praxo.usage(0, 0))
}

options := praxo.agent_options(praxo.callback_model(generate))
result := praxo.run_agent(options, praxo.session('s1', []praxo.Message{}), 'Hi') or { panic(err) }

Current Limits

• Verified with V 0.5.2 and the bundled tcc on Windows. Other V releases, and gcc are not verified; Linux CI runs the same suite.
• JSON is decoded with x.json2. Invalid JSON and trailing data are rejected; duplicate object keys are not a declared vector and should not be treated as a security boundary.
• Tool calls cover canonical JSON, XML-style, dotted tags, and dotted plain lines. Generated call IDs are not provided. Markup stripping is not an authorization control or sanitizer.
• Run IDs combine nanosecond time with a random suffix. They are not a guaranteed global identifier.
• Schema patterns use the V regex module. Unsupported patterns are reported as schema errors rather than silently accepted.
• Path checks are lexical and confined by separator boundaries. They do not resolve symlinks or replace operating-system sandboxing.
• Provider adapters, streaming wire encodings, and plugin hosts are not part of this Core.

The source is MIT; see LICENSE. V and its bundled toolchain are separate projects, not vendored code.

See language policy, parity inventory, and implementation support.