--- title: "JavaScript SDK internals: constructor options, headers, retries and timeouts, env vars, logging, gateways, forward compatibility, migration notes" type: reference tags: [javascript, typescript, sdk, internals, logging, gateways] created: 2026-09-23 updated: 2026-09-23 confidence: high sources: - raw/docs/sdk__javascript.md - raw/docs/sdk__javascript__api.md - raw/docs/sdk__javascript__api__classes__TypeSafeClient.md - raw/docs/sdk__javascript__api__classes__APIPromise.md - raw/docs/sdk__javascript__api__interfaces__Models.md - raw/docs/sdk__javascript__api__interfaces__Logger.md - raw/docs/sdk__javascript__api__interfaces__SystemOneRequest.md - raw/docs/sdk__javascript__api__interfaces__RequestOptions.md - raw/docs/sdk__javascript__api__variables__VERSION.md - raw/docs/sdk__javascript__api__variables__LOG_LEVELS.md - raw/docs/sdk__javascript__api__variables__ENV.md - raw/docs/sdk__javascript__changelog.md - raw/docs/sdk__python__usage.md - raw/github/typesafe-sdk-js/README.md - raw/github/typesafe-sdk-js/package.json - raw/github/typesafe-sdk-js/jsr.json - raw/github/typesafe-sdk-js/examples/demo.ts - raw/github/typesafe-sdk-js/src/index.ts - raw/github/typesafe-sdk-js/src/client.ts - raw/github/typesafe-sdk-js/src/questions.ts - raw/github/typesafe-sdk-js/src/api-promise.ts - raw/github/typesafe-sdk-js/src/retry.ts - raw/github/typesafe-sdk-js/src/logging.ts - raw/github/typesafe-sdk-js/src/env.ts - raw/github/typesafe-sdk-js/src/runtime.ts - raw/github/typesafe-sdk-js/src/version.ts - raw/github/typesafe-sdk-js/src/resources/models.ts - raw/github/typesafe-sdk-js/test/client.test.ts jev_version: "jev-1.13.0" sdk_js: "0.6.0" summary: "@typesafe-ai/sdk 0.6.0 internals: package facts, exports, full constructor options, headers, retries/timeouts, APIPromise, models, env vars, logging, gateways, forward compatibility, migration." --- # JavaScript SDK internals: constructor options, headers, retries and timeouts, env vars, logging, gateways, forward compatibility, migration notes > **TL;DR** The detail behind the builder contract on [[reference/javascript-sdk]]: package facts and entry points (ESM, CJS, JSR), the export list, every `TypeSafeClientConfig` option with verbatim construction errors, instance properties, the headers and wire body the client sends, per-attempt timeouts and retries, `APIPromise` in full, the `models` resource, TypeScript generics, `ENV` / `VERSION`, logging and redaction, pointing `baseURL` at an AI gateway, forward-compatibility escape hatches, and 0.5.7 → 0.6.0 migration. Documents `@typesafe-ai/sdk` 0.6.0. If you just need to make a call, read [[reference/javascript-sdk]] instead. ## Package facts | Fact | Value | Source | |---|---|---| | npm name | `@typesafe-ai/sdk` | `package.json` | | version | `0.6.0` | `package.json`, `src/version.ts` (`VERSION`) | | description | "TypeScript SDK for the TypeSafe API" | `package.json` | | license | MIT | `package.json`, `jsr.json` | | author | `evinism` | `package.json` | | engines | `node >= 20` | `package.json`; docs say "Node.js 20 or newer" | | module type | `"type": "module"` (ESM-first) | `package.json` | | homepage | `https://docs.typesafe.ai/sdk/javascript` | `package.json` | | repository | `https://github.com/typesafe-ai/typesafe-sdk-js` | `package.json` | | issues | `https://github.com/typesafe-ai/typesafe-sdk-js/issues` | `package.json` | | published files | `dist`, `LICENSE`, `README.md` | `package.json` | | `sideEffects` | `false` (tree-shakeable) | `package.json` | | packageManager | `npm@11.19.0` | `package.json` | ### Entry points (ESM + CJS + declarations) `package.json` declares dual exports. The README and docs both state: "The package includes ESM, CommonJS, and TypeScript declarations." | Condition | File | |---|---| | `import` → types | `./dist/index.d.mts` | | `import` → default | `./dist/index.mjs` | | `require` → types | `./dist/index.d.cts` | | `require` → default | `./dist/index.cjs` | | legacy `main` | `./dist/index.cjs` | | legacy `module` | `./dist/index.mjs` | | legacy `types` | `./dist/index.d.cts` | | subpath | `./package.json` only | ESM: ```ts import { choice, noul, score, TypeSafeClient } from "@typesafe-ai/sdk"; ``` CommonJS: ```js const { choice, noul, score, TypeSafeClient } = require("@typesafe-ai/sdk"); ``` There is no deep-import subpath: everything is exported from the package root (`src/index.ts` is the single entry). ### JSR The repo contains a `jsr.json` and npm scripts `push:jsr` / `push:jsr:dry`, so the package is set up for JSR publication: ```json { "name": "@typesafe-ai/sdk", "version": "0.6.0", "license": "MIT", "exports": "./src/index.ts", "publish": { "include": ["src/**/*.ts", "README.md", "LICENSE", "jsr.json"], "exclude": ["src/**/*.test.ts"] } } ``` The JSR entry point is the TypeScript source (`./src/index.ts`), not `dist/`. Whether a JSR release actually exists on jsr.io is **not confirmed by any source in `raw/`**; only npm releases are recorded (see [[reference/javascript-sdk-changelog]]). ## What the package exports From `src/index.ts` (value exports unless marked *type-only*): | Export | Kind | Page | |---|---|---| | `TypeSafeClient` | class | [[reference/javascript-sdk]], this page | | `APIPromise` | class | this page | | `choice`, `score`, `noul` | functions | [[reference/javascript-sdk]] | | `ENV` | const object | this page, [[reference/environment-variables]] | | `LOG_LEVELS` | const array | this page | | `VERSION` | const string `"0.6.0"` | this page | | `TypeSafeError`, `APIError`, `APIConnectionError`, `APITimeoutError`, `APIUserAbortError`, `AuthenticationError`, `BadRequestError`, `InternalServerError`, `NotFoundError`, `PermissionDeniedError`, `RateLimitError`, `UnprocessableEntityError` | classes | [[reference/javascript-sdk-errors]] | | `WithResponse` | *type-only* | [[reference/javascript-sdk-types]] | | `EnvVar` | *type-only* | [[reference/javascript-sdk-types]] | | `Models` | *type-only* (`export type { Models }`) | this page | | everything in `src/types.ts` | *type-only* (`export type * from "./types"`) | [[reference/javascript-sdk-types]] | `Models` is exported as a **type only**, so you cannot `new Models(...)` from the package; you reach it through `client.models`. (The published API reference lists it under "Interfaces"; in source it is a `class`; see the version notes at the bottom.) ## Constructor in full ```ts new TypeSafeClient(config?: TypeSafeClientConfig): TypeSafeClient; ``` "Client for the TypeSafe AI API." Explicit options take precedence over environment variables, then SDK defaults. Empty or whitespace-only environment values are ignored (`readEnv` trims and treats blank as absent). Throws `TypeSafeError` when the API key is missing, configuration is invalid, or the runtime is unsupported. Full property table for `TypeSafeClientConfig` (all properties optional): | Property | Type | Required | Default | Description | |---|---|---|---|---| | `apiKey` | `string` | no (but required in effect) | `TYPESAFE_API_KEY` | Required API key; falls back to the env var. Missing → `TypeSafeError`. | | `baseURL` | `string` | no | `TYPESAFE_BASE_URL`, then `https://api.typesafe.ai` | API root. Trailing slashes are stripped. | | `defaultModel` | `string` | no | `TYPESAFE_DEFAULT_MODEL`, then `jev-latest` | Model used when a request omits `model`. | | `logLevel` | `LogLevel` | no | `TYPESAFE_LOG_LEVEL`, then `warn` | `info` logs request summaries; `debug` adds headers and bodies. Known credential headers are redacted; **bodies are not**. | | `logger` | `Logger` | no | prefixed `console` (`[typesafe-sdk]`) | Logger filtered to `logLevel` and above. | | `retry` | `Partial` | no | `DEFAULT_RETRY_POLICY` | Omitted fields use the `RetryPolicy` defaults. | | `timeout` | `number` (ms) | no | `10000` | Timeout **per attempt**; there is no total retry budget. Must be a positive finite number. | | `defaultHeaders` | `Record` | no | `{}` | Additional request headers; per-call headers take precedence. | | `dangerouslyAllowBrowser` | `boolean` | no | `false` | Allow browser use, exposing the API key to page users. | | `fetch` | `Fetch` | no | global `fetch` | Custom HTTP fetch implementation for transport configuration or tests. | Construction-time failures, all `TypeSafeError` (messages verbatim from `src/client.ts`): - Browser detected and `dangerouslyAllowBrowser` not set: "TypeSafeClient is running in a browser, which would expose your API key to anyone using the page. Call the API from a server instead, or pass `dangerouslyAllowBrowser: true` if you understand the risk." Detection (`isBrowser()` in `src/runtime.ts`) checks for `window.document` and `navigator`. - No key: "No API key was provided. Pass `apiKey` to the TypeSafeClient constructor or set the TYPESAFE_API_KEY environment variable." - No global fetch and no `fetch` option: "No global `fetch` is available in this runtime. Pass a `fetch` implementation to the TypeSafeClient constructor." - Invalid `timeout`: "`timeout` must be a positive number of milliseconds, got X." ### Instance properties All are `readonly`. The API key is stored in a private field (`#apiKey`) and is not a public property. | Property | Type | Description | |---|---|---| | `baseURL` | `string` | API root with trailing slashes removed. | | `defaultModel` | `string` | Model used when a request omits `model`. | | `logLevel` | `LogLevel` | Configured log verbosity. | | `logger` | `Logger` | The configured logger, filtered to `logLevel`. | | `retry` | `RetryPolicy` | Retry settings with constructor overrides applied (fully resolved, not partial). | | `timeout` | `number` | Timeout per attempt in milliseconds. | | `defaultHeaders` | `Readonly>` | Additional headers sent with each request. | | `fetch` | `Fetch` | HTTP fetch implementation. | | `models` | `Models` | The models available to the account. | ## `systemOne()` internals Upstream example (JSDoc in `src/client.ts`): ```ts const { answers } = await client.systemOne({ state: "I was charged twice. Please help.", questions: { billing: noul("Is this about billing?") }, }); console.log(answers.billing.noul); ``` Wire behaviour: the SDK validates questions locally, then `POST`s `{...request, model: request.model ?? client.defaultModel}` (a `SystemOneRequestPayload`) to `POST /v1/systemone`. Additional properties on a request *variable* are forwarded, including `null` values (see [Forward compatibility](#forward-compatibility)). See [[reference/http-api]]. ### Question validation Builder-time throws (`TypeSafeError`, from `src/questions.ts`): - `choice()` given an array: "Choice criteria must be a map of labels to descriptions, not a list." - `score()` given an object: "Score criteria must be a list of descriptions indexed by score from zero, not a map." `systemOne()` calls `validateQuestions` before sending. It throws `TypeSafeError` for: - an empty object: "At least one question is required." - a `score` question whose `criteria` is not an array: `Score question "" has criteria that are not a list; score criteria must be a list of descriptions indexed by score from zero.` - a `score` question with fewer than two criteria: `Score question "" has N criteria; at least two scores are required.` `choice` and `noul` questions are not otherwise validated client-side. ## Headers the client sends Built in `fetchWithRetries`. User-supplied headers are merged first so they cannot clobber auth or the JSON content type; header matching is case-insensitive, last value wins. Per-call `headers` are merged over `defaultHeaders`. | Header | Value | |---|---| | `Authorization` | `Bearer ` | | `Accept` | `application/json` | | `User-Agent` | `typesafe-sdk/0.6.0` | | `X-TypeSafe-SDK` | `typesafe-sdk/0.6.0` | | `X-TypeSafe-Runtime` | e.g. `node/22.1.0 (darwin; arm64)`, `bun/`, `deno/`, `vercel-edge`, `cloudflare-workers`, `browser`, `unknown` | | `Content-Type` | `application/json` when there is a body; omitted otherwise | | `X-TypeSafe-Retry-Count` | absent on the first attempt; `"1"`, `"2"`, … on retries | The response request ID is read from `x-typesafe-request-id`. **`defaultHeaders` cannot override auth**: `Authorization`, `Accept`, `User-Agent`, `X-TypeSafe-SDK`, `X-TypeSafe-Runtime`, and `Content-Type` are merged last and win. ## Retries and timeouts `DEFAULT_RETRY_POLICY` (`src/retry.ts`): `maxRetries: 2`, backoff 500 ms doubling to 5000 ms with 0.25 jitter, retries HTTP 408, 429 and 500–599 plus `APIConnectionError` and `APITimeoutError`, honours `retry-after-ms` / `Retry-After` up to 60000 ms. `APIUserAbortError` is never retried. The full `RetryPolicy` and `RequestOptions` tables, the delay formula and the status-to-class map are on [[reference/javascript-sdk-errors]]. - **`timeout` is per attempt, not per call.** With `maxRetries: 2` and `timeout: 10000`, worst-case wall time is roughly three attempts plus backoff. - **The body is fully buffered before the promise resolves**, under the same timeout, so a slow body counts against the attempt. - A caller `signal` cancels the in-flight attempt and any pending retry wait; both surface as `APIUserAbortError`. - Per-call `retry` inherits unset fields from the client's resolved policy; per-call `timeout` must also be a positive finite number. Per-call overrides (built from the `RequestOptions` fields; not an upstream sample): ```ts import { noul, TypeSafeClient } from "@typesafe-ai/sdk"; const client = new TypeSafeClient({ timeout: 5000, retry: { maxRetries: 1 } }); const controller = new AbortController(); const result = await client.systemOne( { state: "I was charged twice.", questions: { billing: noul("Is this about billing?") } }, { timeout: 3000, retry: { maxRetries: 0 }, headers: { "X-Request-Source": "support-bot" }, signal: controller.signal, }, ); console.log(result.answers.billing.noul); ``` ## `APIPromise` in full `systemOne()` and `models.list()` return `APIPromise`, a `Promise` subclass. "Non-2xx responses reject with an `APIError`, including through `asResponse()`." The body is parsed lazily and at most once; `then`/`catch`/`finally` are overridden to go through that single parse. | Method | Signature | Description | |---|---|---| | `asResponse()` | `(): Promise` | The raw `Response` without parsing the body. SDK requests buffer the full body under the request timeout before handoff; reading it afterwards is caller-owned. Don't also `await` the parsed result on the same promise. | | `withResponse()` | `(): Promise>` | `{ data, response, requestId }`: parsed result, HTTP response, and request ID from `x-typesafe-request-id`. Example on [[reference/javascript-sdk]]. | | `map(fn)` | `(fn: (data: T) => U): APIPromise` | Transform the parsed result, sharing the HTTP response and a single body parse. | | `then(onfulfilled?, onrejected?)` | overrides `Promise.then` | Parsed result. | | `catch(onrejected?)` | overrides `Promise.catch` | — | | `finally(onfinally?)` | overrides `Promise.finally` | — | Constructor (public but intended for internal use): `new APIPromise(responsePromise: Promise, parseResponse: (response: Response) => Promise)`. Because the body is buffered, `asResponse()` hands you a response whose body is already readable, but don't consume both `asResponse()` and the parsed value on the same `APIPromise`. **Response parsing is lenient**: bodies are `JSON.parse`d even when `content-type` is missing, falling back to the raw text, and an empty body parses to `undefined`. ## `models` resource ```ts client.models.list(options?: RequestOptions): APIPromise ``` "List the models available to the account." Calls `GET /v1/models` and unwraps the `{ models: [...] }` envelope; a response of any other shape raises `TypeSafeError` "Unexpected response shape from GET /v1/models; expected { models: [...] }." `ModelCard`: `{ readonly name: string; readonly description: string; readonly release_date: string }`. Catalogue and pricing live in [[reference/models-and-pricing]]. ```ts const models = await client.models.list(); console.log(models.map((m) => `${m.name} (${m.release_date})`).join("\n")); ``` ## TypeScript generics in practice The `const` type parameter is what preserves literal label and tuple types, so you get narrowed keys without any manual annotation: ```ts import { choice, score, TypeSafeClient } from "@typesafe-ai/sdk"; import type { ChoiceResponse, ScoreResponse, SystemOneResult } from "@typesafe-ai/sdk"; const client = new TypeSafeClient(); const questions = { tone: choice("What is the customer's tone?", { calm: null, angry: null }), urgency: score("How urgent is this?", ["can wait", "today", "right now"]), } as const; const result: SystemOneResult = await client.systemOne({ state: "My account is locked and I have a demo in ten minutes.", questions, }); // `tone.choice` is "calm" | "angry", not string: const tone: ChoiceResponse<{ calm: null; angry: null }> = result.answers.tone; if (tone.choice === "angry") console.log("escalate"); // `urgency.probabilities` is keyed "0" | "1" | "2": const urgency: ScoreResponse = result.answers.urgency; console.log(urgency.probabilities["2"], urgency.legend["2"]); ``` Writing questions inline in the `systemOne({ questions: { ... } })` call gives the same inference, because `systemOne` itself declares ``. ## Environment variables and `VERSION` `ENV` maps config keys to env var names (see [[reference/environment-variables]]): | `ENV` key | Env var | Effect | |---|---|---| | `ENV.apiKey` | `TYPESAFE_API_KEY` | Required API key; used when `apiKey` is omitted. | | `ENV.baseURL` | `TYPESAFE_BASE_URL` | API root; defaults to `https://api.typesafe.ai`. | | `ENV.defaultModel` | `TYPESAFE_DEFAULT_MODEL` | Default model name; defaults to `jev-latest`. | | `ENV.logLevel` | `TYPESAFE_LOG_LEVEL` | Log level; defaults to `warn`. | `VERSION` is the string literal type `"0.6.0"`, kept in sync with `package.json` and checked by `npm run check:version`. ## Logging | Item | Value | |---|---| | `LOG_LEVELS` | `readonly LogLevel[]` = `["debug", "info", "warn", "error", "off"]`, most to least verbose | | `LogLevel` | `"debug" \| "info" \| "warn" \| "error" \| "off"` (`off` disables logging) | | default level | `warn` (`DEFAULT_LOG_LEVEL`) | | default logger | `console` with the prefix `[typesafe-sdk]` | | `Logger` | `{ debug, info, warn, error }`, each `(message: string, ...args: unknown[]) => void`; `console` satisfies it | What gets logged: `info` emits per-attempt summaries (`#3 POST /v1/systemone <- 200 in 412ms (request req_…)`, timeouts, aborts, retry waits). `debug` additionally logs outgoing URL + headers + body and the parsed response body. Redaction covers `authorization`, `proxy-authorization`, `x-api-key` (masked to `Bearer ***abcd`, keeping the scheme and the last four characters of secrets longer than eight) and `cookie` / `set-cookie` (`***`). **Request and response bodies are not redacted**: do not use `debug` on production traffic containing personal data. An invalid level from either the option or `TYPESAFE_LOG_LEVEL` throws `TypeSafeError`: `Invalid log level "X" from . Expected one of: debug, info, warn, error, off.` Routing SDK logs into your own logger (`myLogger` stands for your application's logger): ```ts const client = new TypeSafeClient({ logLevel: "debug", logger: { debug: (m, ...a) => myLogger.trace({ a }, m), info: (m, ...a) => myLogger.info({ a }, m), warn: (m, ...a) => myLogger.warn({ a }, m), error: (m, ...a) => myLogger.error({ a }, m), }, }); ``` ## Pointing the client at another base URL (AI gateways) The JS docs do not document gateways. The mechanism is the same as in Python: the client sends to `` `${baseURL}/v1/systemone` `` and `` `${baseURL}/v1/models` `` (`src/client.ts`), and the constructor checks only that a key is present. The gateway values below are documented only in the Python usage guide (`raw/docs/sdk__python__usage.md`), which adds: "This requires the alternative API to follow the TypeSafe OpenAPI spec." Using them from JS is **(inferred, not tested)**. | Gateway | `apiKey` | `baseURL` | `defaultModel` | |---|---|---|---| | OpenRouter | OpenRouter key (`OPENROUTER_API_KEY` in the Python sample) | `https://openrouter.ai/api` | `~typesafe/jev-latest` | | Vercel AI Gateway | `AI_GATEWAY_API_KEY` | `https://ai-gateway.vercel.sh/typesafe` | `typesafe-ai/jev` | ```ts import { noul, TypeSafeClient } from "@typesafe-ai/sdk"; const client = new TypeSafeClient({ apiKey: process.env.OPENROUTER_API_KEY, baseURL: "https://openrouter.ai/api", defaultModel: "~typesafe/jev-latest", }); const { answers } = await client.systemOne({ state: "I was charged twice.", questions: { billing: noul("Is this about billing?") }, }); console.log(answers.billing.noul); ``` The `X-TypeSafe-*` headers above are sent to the gateway too. Neither gateway's pricing or rate limits are covered by [[reference/models-and-pricing]]; worked Python versions are on [[reference/python-sdk-internals]]. ## Forward compatibility | Need | Mechanism | |---|---| | Send a request field newer than the SDK | Put it on a request *variable* and pass that: "Additional properties on a request variable are forwarded, including `null` values" (docs; `test/client.test.ts` "forwards extra fields and null"). An inline object literal with an unknown key would hit TypeScript's excess-property check (inferred). | | Send a question field newer than the SDK | The whole request object is `JSON.stringify`d as-is and `validateQuestions` checks only score criteria, so an extra key on a question object is sent (inferred from `src/client.ts`, not tested upstream). | | Read an answer kind or field newer than the SDK | `systemOne()` does no runtime validation of the response body (the parsed JSON is cast to `SystemOneResult`), so unknown fields and answer types arrive untouched; the TypeScript types just do not describe them (inferred from `src/client.ts`). | | Unexpected `GET /v1/models` shape | Only the `{ models: [...] }` envelope is checked; anything else throws `TypeSafeError`. | ```ts import { score, TypeSafeClient } from "@typesafe-ai/sdk"; const client = new TypeSafeClient(); const request = { state: "s", questions: { q: score("?", ["low", "high"]) }, future_option: null, nested: { enabled: true }, }; await client.systemOne(request); // body is { ...request, model: "jev-latest" } ``` The request object above is the one `test/client.test.ts` uses; the test then confirms a later call without the extra keys does not send `future_option`. ## Migrating from 0.5.7 The only recorded change in 0.6.0 is breaking: "accept `Score.criteria` as an ordered sequence instead of a dictionary keyed by integers". Replace `score(q, {0: "...", 1: "..."})` with `score(q, ["...", "..."])`; index 0 stays the lowest level, so `score`, `legend` and `probabilities` keep their meaning. Before/after code: [[reference/javascript-sdk-changelog]]. ## CommonJS example `examples/demo.ts` (full ESM version on [[reference/javascript-sdk]]) uses top-level `await`, so it must run as ESM. The CommonJS equivalent wraps the body in an async IIFE: ```js const { APIError, choice, noul, score, TypeSafeClient } = require("@typesafe-ai/sdk"); (async () => { const client = new TypeSafeClient({ logLevel: "info" }); try { const { answers, usage } = await client.systemOne({ state: { subject: "Charged twice this month", body: "Two $49 charges in August." }, questions: { isBilling: noul("Is this ticket about billing?"), sentiment: choice("What is the customer's tone?", { calm: null, frustrated: null, angry: null, }), urgency: score("How urgent is this ticket?", ["can wait", "this week", "today", "right now"]), }, }); console.log(answers.isBilling.noul, answers.sentiment.choice, answers.urgency.score); console.log(usage.input_tokens, usage.output_tokens); } catch (err) { if (err instanceof APIError) { console.error(`API error ${err.status} (request ${err.requestId ?? "unknown"}):`, err.body); } else { throw err; } } })(); ``` ## Version notes - This page describes `@typesafe-ai/sdk` 0.6.0 (repo commit `66880ccded6cb642dc1809620c2b108c33730214`, 2026-09-15). - **Doc-vs-source discrepancy:** the published API reference lists `Models` under *Interfaces* (`# Interface: Models`), but `src/resources/models.ts` declares `export class Models` with a constructor taking an internal `Transport`. Because `src/index.ts` re-exports it with `export type { Models }`, only the type is importable: the docs' classification is accurate from a consumer's point of view, but the source is a class. - The docs' `ChoiceCriteria` index signature renders as `[label: string]: EntryType`; source writes `[label: string]: Description`, and `Description = EntryType`, so they are the same type. - 2026-09-23: this page was split out of [[reference/javascript-sdk]], which now carries only the builder contract. ## Related - [[reference/javascript-sdk]] — the builder contract: install, client, `systemOne()`, builders, answers, errors - [[reference/javascript-sdk-types]] — every interface and type alias in detail - [[reference/javascript-sdk-errors]] — error classes, `RetryPolicy`, `RequestOptions` - [[reference/javascript-sdk-changelog]] — release history and the 0.6.0 migration code - [[reference/environment-variables]] — `TYPESAFE_*` across SDKs - [[reference/http-api]] — the wire contract behind `systemOne()` and `models.list()` - [[reference/python-sdk-internals]] — the Python equivalent, with the documented gateway samples ## Sources - raw/docs/sdk__javascript.md (https://docs.typesafe.ai/sdk/javascript) - raw/docs/sdk__javascript__api.md (https://docs.typesafe.ai/sdk/javascript/api) - raw/docs/sdk__javascript__api__classes__TypeSafeClient.md (https://docs.typesafe.ai/sdk/javascript/api/classes/TypeSafeClient) - raw/docs/sdk__javascript__api__classes__APIPromise.md (https://docs.typesafe.ai/sdk/javascript/api/classes/APIPromise) - raw/docs/sdk__javascript__api__interfaces__Models.md, __Logger.md, __SystemOneRequest.md, __RequestOptions.md - raw/docs/sdk__javascript__api__variables__VERSION.md, __LOG_LEVELS.md, __ENV.md - raw/docs/sdk__javascript__changelog.md (https://docs.typesafe.ai/sdk/javascript/changelog) - raw/docs/sdk__python__usage.md (https://docs.typesafe.ai/sdk/python/usage.md) — gateway values - raw/github/typesafe-sdk-js (https://github.com/typesafe-ai/typesafe-sdk-js, commit 66880ccded6cb642dc1809620c2b108c33730214): README.md, package.json, jsr.json, examples/demo.ts, src/index.ts, src/client.ts, src/questions.ts, src/api-promise.ts, src/retry.ts, src/logging.ts, src/env.ts, src/runtime.ts, src/version.ts, src/resources/models.ts, test/client.test.ts