Date: 2026-05-06
Build a Rust CLI tool for testing an LLM relay service. The tool should start with reliable single-request checks, then grow into RPM/concurrency testing and dataset-based accuracy evaluation.
The first implementation will use a modular single-crate architecture. This keeps initialization light while still giving clear boundaries for config loading, CLI parsing, protocol adapters, request execution, benchmarks, and metrics.
First phase:
Later phase:
Use scheme B: one binary crate split into internal modules.
Planned structure:
src/
main.rs
cli.rs
config.rs
runner.rs
metrics.rs
protocols/
mod.rs
openai.rs
anthropic.rs
benchmark/
mod.rs
dataset.rs
judge.rs
Module responsibilities:
cli: Defines subcommands and flags using clap.config: Loads YAML config, resolves environment variable references, and validates provider settings.protocols: Converts internal request data into provider-specific HTTP requests and parses responses.runner: Executes one logical model request and returns response text, elapsed time, provider metadata, and errors.benchmark: Reads JSONL test cases, runs them through the runner, and judges answers.metrics: Aggregates latency, success rate, error distribution, and accuracy summaries.main: Wires the CLI, config, runner, and command handlers together.Initial commands:
lq_token_test check --config config.yaml --provider openai --model gpt-4o-mini --prompt "hello"
lq_token_test bench --config config.yaml --provider openai --dataset benchmarks/smoke.jsonl --concurrency 4
lq_token_test rpm --config config.yaml --provider openai --rpm 60 --duration 60s --prompt "hello"
The check command proves that a relay, token, model, and protocol shape work.
The bench command runs local JSONL cases and reports accuracy plus request metrics.
The rpm command sends repeated requests at a target rate and reports latency and error behavior.
Example:
default_provider: openai
providers:
openai:
protocol: openai
base_url: "https://relay.example.com/v1"
api_token: "${OPENAI_RELAY_TOKEN}"
default_model: "gpt-4o-mini"
anthropic:
protocol: anthropic
base_url: "https://relay.example.com"
api_token: "${ANTHROPIC_RELAY_TOKEN}"
default_model: "claude-3-5-sonnet-latest"
benchmarks:
smoke:
path: "benchmarks/smoke.jsonl"
kind: "qa_exact"
API tokens should be allowed directly in YAML for local testing, but environment variable references are preferred.
Use JSONL so datasets can be streamed and edited without custom tooling.
Example:
{"id":"smoke_001","question":"What is 2 + 2?","answer":"4","kind":"exact"}
{"id":"gsm8k_001","question":"Natalia sold clips and earned 72 dollars. How much did she earn?","answer":"72","kind":"gsm8k"}
Judging rules:
exact: normalize whitespace and compare the full answer.gsm8k: extract the final numeric answer from model output and compare with the expected answer.The first phase accuracy score is an internal evaluation signal. It should not be presented as matching or disproving official model accuracy until dataset version, prompt template, sample count, temperature, and scoring method are aligned with the official report.
Recommended crates:
clap: CLI parser and subcommands.serde, serde_yaml, serde_json: config and dataset parsing.tokio: async runtime.reqwest: HTTP client.anyhow: simple top-level CLI error handling.thiserror: structured module-level errors.tracing, tracing-subscriber: logs.indicatif: progress display for benchmark and RPM runs.hdrhistogram: latency percentiles.regex: answer extraction for GSM8K-style judging.Prefer reqwest with Rustls TLS. Avoid provider SDKs in the first phase so protocol compatibility remains transparent and easy to inspect.
The CLI should surface concise user-facing errors:
Benchmark and RPM commands should continue after per-request failures and include failures in the final summary.
Initial tests should cover:
Network tests should be kept opt-in because they require real relay credentials.
/chat/completions.