npx skills add ...
npx skills add langchain-ai/deepagentsjs --skill eval-writer
npx skills add langchain-ai/deepagentsjs --skill eval-writer
Create new eval suites for the deepagentsjs monorepo. Handles dataset design, test case scaffolding, scoring logic, vitest configuration, and LangSmith integration. Use when the user asks to: (1) create an eval, (2) write an evaluation, (3) add a benchmark, (4) build an eval suite, (5) evaluate agent behaviour, (6) add test cases for a capability, or (7) implement an existing benchmark (e.g. oolong, AgentBench, SWE-bench). Trigger on phrases like 'create eval', 'new eval', 'add eval', 'benchmark', 'evaluate', 'eval suite', 'write evals for'.
Create new eval suites for the deepagentsjs monorepo. Each eval is an
independent workspace package under evals/ that uses the @deepagents/evals
harness, runs via vitest, and reports results to LangSmith.
Read the existing eval infrastructure to understand current patterns:
Scan existing evals for conventions:
Clarify with the user:
Every eval is a workspace package under evals/<name>/.
Add extra dependencies as needed (e.g. zod for tool schemas, langchain
for tool() helper, dataset-specific packages).
Adjust testTimeout for long-running evals (multi-turn, code execution).
Add "./vitest.setup.ts" to setupFiles if the eval needs custom setup (dataset loading, etc.).
Check that pnpm-workspace.yaml includes "evals/*". It should already
be there — if not, add it.
Best for small, hand-crafted test suites. Each test is an ls.test() call
with inputs and optional referenceOutputs.
Best for 10-200 cases from a fixture file. Load the data and iterate:
The fixture JSON must be an array of objects with at minimum { inputs: {...} }.
Optional fields: referenceOutputs, id, metadata, split.
For published benchmarks (oolong, AgentBench, SWE-bench, etc.), download and cache the dataset in a setup file.
Create vitest.setup.ts:
Add .cache/ to .gitignore in the eval package.
Then register it as a vitest setup file in vitest.config.ts:
And in the test file:
Pull test cases from a LangSmith dataset. Useful for collaborative curation where non-engineers add examples via the LangSmith UI.
The harness provides vitest matchers that also log LangSmith feedback scores. Use these as the primary building blocks:
Log additional LangSmith feedback scores beyond what matchers provide:
For subjective quality, use ls.wrapEvaluator() to create a traced evaluator
that logs feedback automatically:
getDefaultRunner() — reads EVAL_RUNNER env var. Throws if not set.runner.name — used as ls.describe name → becomes the LangSmith dataset name.runner.run({ query, initialFiles? }) — pure invocation. Returns AgentTrajectory.runner.extend({ systemPrompt?, tools?, subagents?, ... }) — returns a new runner with agent config overrides. Use for tests that need custom agent setup.projectName in ls.describe config — sets the LangSmith project for tracing. Convention: "deepagents-js-<eval-name>".upsert: true — reuse existing dataset/project instead of creating new ones each run.expect from vitest — the harness extends it with custom matchers at import time.ls.logOutputs() is called inside the runner — do NOT call it in test code.The default eval runners use the in-memory StateBackend — the agent can
read/write files but cannot execute shell commands, install packages, or
interact with a real OS. This is fine for testing tool selection, reasoning,
and file operations.
For evals that need real execution (SWE-bench, code generation, agentic benchmarks), the agent must run against a sandbox backend. Available sandbox providers:
| Provider | Package | Use case |
|---|---|---|
| Modal | @deepagents/modal | Remote containers, GPU support |
| Daytona | @deepagents/daytona | Cloud dev environments |
| Deno | @deepagents/deno | Lightweight local sandboxes |
| Node VFS | @deepagents/node-vfs | In-process virtual filesystem + shell |
Pass the sandbox via extend({ backend }). Manage its lifecycle with
beforeAll / afterAll (suite-level) or beforeEach / afterEach
(per-test isolation):
For per-test isolation (each test gets a fresh sandbox):
When to containerize:
execute() (shell commands)When in-memory is fine:
StateBackend + initialFiles)Add the sandbox provider to package.json dependencies:
And increase testTimeout in vitest.config.ts — sandbox creation adds
overhead:
Add the new eval to evals/README.md in the "Available eval suites" table:
The Python deepagents package has eval suites in
libs/deepagents/tests/evals/. The JS evals should maintain parity.
When creating a new eval, check the Python source at
https://github.com/langchain-ai/deepagents/blob/v0.5/libs/deepagents/tests/evals/
for the reference implementation.
| Python eval | JS eval | Status |
|---|---|---|
test_system_prompt.py | evals/basic/ | ✅ Covered |
test_file_operations.py | evals/files/ | ✅ Covered |
test_subagents.py | evals/subagents/ | ✅ Covered |
test_memory.py | evals/memory/ | ✅ Covered |
test_hitl.py | evals/hitl/ | ✅ Covered |
test_skills.py | evals/skills/ | ✅ Covered |
test_summarization.py | evals/summarization/ | ❌ Missing |
HITL evals require multi-step invocation (invoke → check interrupts → resume
with Command). The eval runner's run() does a single invocation, so HITL
tests construct agents directly via createDeepAgent() with a checkpointer
and interruptOn config. See evals/hitl/index.test.ts for the pattern.
Summarization evals need SummarizationMiddleware with low token thresholds,
a checkpointer, a real/virtual filesystem backend, and multi-turn invocations.
These tests would bypass the standard EvalRunner and construct agents
directly, similar to HITL.
ls.test.each is the most powerful pattern for data-driven evals. The table
must be an array of objects with at least { inputs }:
| Concept | LangSmith entity |
|---|---|
ls.describe(name, ...) | Dataset (name = dataset name) |
ls.test(name, { inputs, referenceOutputs }, fn) | Example in dataset |
| Running the test suite | Experiment on the dataset |
ls.logFeedback(...) | Feedback on the experiment run |
ls.logOutputs(...) | Experiment output (called by runner) |
| Variable | Purpose |
|---|---|
EVAL_RUNNER | Which model runner to use (e.g. sonnet-4-5) |
LANGSMITH_API_KEY | LangSmith auth |
LANGSMITH_PROJECT | Override tracing project (normally set via projectName) |
LANGSMITH_TEST_TRACKING | Set to "false" to disable LangSmith reporting |
ANTHROPIC_API_KEY | For Anthropic model runners |
OPENAI_API_KEY | For OpenAI model runners |
Defined in internal/eval-harness/src/setup.ts:
| Runner name | Model |
|---|---|
sonnet-4-5 | Claude Sonnet 4.5 |
sonnet-4-5-thinking | Claude Sonnet 4.5 with extended thinking |
opus-4-6 | Claude Opus 4.6 |
gpt-4.1 | GPT-4.1 |
gpt-4.1-mini | GPT-4.1 Mini |
o3-mini | o3-mini |
When implementing an existing benchmark, follow these attribution and methodology guidelines.
Always credit the original benchmark authors. In the eval's README.md:
ls.test.each with fixture JSONrunner.run() calls sharing state, or multi-message queriesrunner.extend({ tools: [...] }) with custom tools that return canned responsesrunner.extend({ backend: sandbox }), write code to file, execute tests via sandboxinitialFiles, check final textStateBackend is sufficientrunner.extend({ backend: sandbox }) with per-test sandbox isolationFor benchmarks with thousands of cases:
split field in test cases to categorise (e.g. "easy", "hard"). Run subsets via vitest filtering..cache/ (gitignored).--dry-run that validates fixtures without calling the LLM.{
"name": "@deepagents/eval-<name>",
"private": true,
"type": "module",
"scripts": {
"test:eval": "vitest run"
},
"dependencies": {
"@deepagents/evals": "workspace:*",
"deepagents": "workspace:*",
"langsmith": "^0.5.4",
"vitest": "^4.0.18"
}
}import { defineConfig } from "vitest/config";
export default defineConfig({
test: {
environment: "node",
globals: false,
testTimeout: 120_000,
hookTimeout: 60_000,
teardownTimeout: 60_000,
include: ["**/*.test.ts"],
setupFiles: ["@deepagents/evals/setup"],
reporters: ["default", "langsmith/vitest/reporter"],
},
});# <name>
<One-line description of what this eval tests.>ls.test(
"descriptive test name",
{
inputs: { query: "What is 2+2?" },
referenceOutputs: { expectedAnswer: "4" },
},
async ({ inputs, referenceOutputs }) => {
const result = await runner.run({ query: inputs.query });
// assertions...
},
);import testCases from "./fixtures/cases.json";
// testCases = [{ inputs: { query: "..." }, referenceOutputs: { answer: "..." } }, ...]
ls.test.each(testCases)(
"case: ${inputs.query}",
async ({ inputs, referenceOutputs }) => {
const result = await runner.run({ query: inputs.query });
// assertions using referenceOutputs...
},
);import { existsSync, mkdirSync, writeFileSync, readFileSync } from "fs";
import { join } from "path";
const CACHE_DIR = join(import.meta.dirname, ".cache");
const DATA_PATH = join(CACHE_DIR, "dataset.json");
export async function loadDataset(): Promise<TestCase[]> {
if (existsSync(DATA_PATH)) {
return JSON.parse(readFileSync(DATA_PATH, "utf-8"));
}
mkdirSync(CACHE_DIR, { recursive: true });
// Download from source — adapt to the specific benchmark
const response = await fetch("https://example.com/dataset.json");
const data = await response.json();
// Transform into eval format
const cases = data.map((item: any) => ({
inputs: { query: item.question },
referenceOutputs: { answer: item.gold_answer },
metadata: { source: item.id, category: item.category },
}));
writeFileSync(DATA_PATH, JSON.stringify(cases, null, 2));
return cases;
}setupFiles: ["@deepagents/evals/setup", "./vitest.setup.ts"],import { loadDataset } from "./vitest.setup.js";
const dataset = await loadDataset();
ls.describe(runner.name, () => {
ls.test.each(dataset)(
"${metadata.source}: ${inputs.query}",
async ({ inputs, referenceOutputs }) => {
// ...
},
);
}, { projectName: "deepagents-js-<name>", upsert: true });import { Client } from "langsmith";
const client = new Client();
export async function loadDataset(): Promise<TestCase[]> {
const examples = [];
for await (const example of client.listExamples({
datasetName: "my-dataset-name",
})) {
examples.push({
id: example.id,
inputs: example.inputs,
referenceOutputs: example.outputs ?? {},
});
}
return examples;
}// Exact step count
expect(result).toHaveAgentSteps(3);
// Exact tool-call count across all steps
expect(result).toHaveToolCallRequests(2);
// Check a specific tool call in step N (1-indexed)
expect(result).toHaveToolCallInStep(1, {
name: "write_file",
argsContains: { file_path: "/out.txt" }, // partial match
argsEquals: { file_path: "/out.txt" }, // exact match
});
// Final response text
expect(result).toHaveFinalTextContaining("hello", true /* caseInsensitive */);
// Extract final text for custom assertions
import { getFinalText } from "@deepagents/evals";
const text = getFinalText(result);
expect(text.trim()).toBe("4");
// File system assertions
expect(result.files["/output.md"]).toContain("expected content");
expect(Object.keys(result.files)).toHaveLength(3);import * as ls from "langsmith/vitest";
// Numeric score
ls.logFeedback({ key: "accuracy", score: 0.95 });
// Boolean score
ls.logFeedback({ key: "correct", score: 1 });
// With comment
ls.logFeedback({ key: "quality", score: 0.8, comment: "Minor formatting issue" });import * as ls from "langsmith/vitest";
import { ChatAnthropic } from "@langchain/anthropic";
const judge = new ChatAnthropic({ model: "claude-sonnet-4-5-20250929" });
const evaluateHelpfulness = ls.wrapEvaluator(
async ({ inputs, outputs, referenceOutputs }) => {
const response = await judge.invoke([
{
role: "system",
content: `Rate the helpfulness of the assistant's response on a scale of 0-1.
Respond with JSON: { "score": <number>, "reasoning": "<explanation>" }`,
},
{
role: "user",
content: `Question: ${inputs.query}\nExpected: ${referenceOutputs.answer}\nActual: ${outputs.response}`,
},
]);
const parsed = JSON.parse(response.content as string);
return {
key: "helpfulness",
score: parsed.score,
comment: parsed.reasoning,
};
},
);
// In a test:
const result = await runner.run({ query: inputs.query });
const text = getFinalText(result);
await evaluateHelpfulness({
inputs: { query: inputs.query },
outputs: { response: text },
referenceOutputs: referenceOutputs ?? {},
});import * as ls from "langsmith/vitest";
import { expect } from "vitest";
import { getDefaultRunner, getFinalText } from "@deepagents/evals";
const runner = getDefaultRunner();
ls.describe(
runner.name,
() => {
ls.test(
"test name",
{
inputs: { query: "..." },
referenceOutputs: { answer: "..." },
},
async ({ inputs, referenceOutputs }) => {
const result = await runner.run({ query: inputs.query });
expect(result).toHaveAgentSteps(1);
expect(result).toHaveFinalTextContaining(referenceOutputs.answer);
},
);
},
{ projectName: "deepagents-js-<name>", upsert: true },
);// Custom system prompt
const result = await runner
.extend({ systemPrompt: "You are a code reviewer." })
.run({ query: inputs.query });
// Custom tools
const result = await runner
.extend({ tools: [myCustomTool] })
.run({ query: inputs.query });
// Custom subagents
const result = await runner
.extend({
subagents: [{
name: "researcher",
description: "Research assistant",
systemPrompt: "You help with research.",
tools: [searchTool],
}],
})
.run({ query: inputs.query });const result = await runner.run({
query: "Read /data.csv and count the rows.",
initialFiles: {
"/data.csv": "name,age\nAlice,30\nBob,25\n",
},
});import * as ls from "langsmith/vitest";
import { expect, beforeAll, afterAll } from "vitest";
import { getDefaultRunner, getFinalText } from "@deepagents/evals";
import { ModalSandbox } from "@deepagents/modal";
const runner = getDefaultRunner();
let sandbox: ModalSandbox;
beforeAll(async () => {
sandbox = await ModalSandbox.create({
image: "python:3.12-slim",
timeout: 600,
});
});
afterAll(async () => {
await sandbox?.terminate();
});
ls.describe(
runner.name,
() => {
ls.test(
"agent can run python",
{ inputs: { query: "Write a Python script that prints 'hello' and run it." } },
async ({ inputs }) => {
const result = await runner
.extend({ backend: sandbox })
.run({ query: inputs.query });
expect(result).toHaveFinalTextContaining("hello");
},
);
},
{ projectName: "deepagents-js-sandbox-eval", upsert: true },
);import { beforeEach, afterEach } from "vitest";
let sandbox: ModalSandbox;
beforeEach(async () => {
sandbox = await ModalSandbox.create({ image: "python:3.12-slim" });
});
afterEach(async () => {
await sandbox?.terminate();
});{
"dependencies": {
"@deepagents/modal": "workspace:*"
}
}testTimeout: 300_000, // 5 minutes for sandbox evals
hookTimeout: 120_000, // sandbox setup/teardown# From repo root
pnpm install
# Build the harness (if you changed it)
cd internal/eval-harness && pnpm build && cd ../..
# Run the new eval
EVAL_RUNNER=sonnet-4-5 pnpm --filter @deepagents/eval-<name> test:eval| [`<name>/`](./<name>/) | <one-line description> |ls.test.each([
{ inputs: { query: "Q1" }, referenceOutputs: { answer: "A1" } },
{ inputs: { query: "Q2" }, referenceOutputs: { answer: "A2" } },
// Optional additional fields: id, metadata, split
{ id: "custom-id", inputs: { query: "Q3" }, referenceOutputs: { answer: "A3" }, split: "hard" },
])(
"case: ${inputs.query}", // Name template — interpolates from row
async ({ inputs, referenceOutputs, testMetadata }) => {
// testMetadata.exampleId, testMetadata.datasetId, etc.
const result = await runner.run({ query: inputs.query });
// ...
},
);# <benchmark-name>
Implementation of [<Benchmark Name>](<paper-or-repo-url>) by <authors> (<year>).
> <brief description from the paper abstract>
## Citation
\`\`\`bibtex
@article{...}
\`\`\`
## Adaptations
<Describe any differences from the original benchmark methodology:>
- <e.g. "Subset of N cases selected for cost efficiency">
- <e.g. "Adapted for agentic tool-use evaluation rather than direct QA">
- <e.g. "Uses LLM-as-judge instead of human annotation">