Multimeter is a Git-native REST client and API testing tool for VS Code. Requests, tests, mocks, and docs are YAML .mmt files in Git — the same files in the visual editor and in CI via testlight. Apache 2.0. No account.

How do I use Multimeter with Cursor, Copilot, or Claude?

Install the VS Code/Cursor extension or add MCP with npx -y mmt-mcp. Agents should call scaffold_test, validate, format, and run instead of guessing .mmt syntax.

Yes. Apache License 2.0. No account required.

Live variables — Multimeter docs

Environment values that start with ./ and end with .mmt are file-backed live variables. Instead of a fixed string, the value points at another .mmt file.…Markdown (no JavaScript)# Live variables Environment values that start with `./` and end with `.mmt` are **file-backed live variables**. Instead of a fixed string, the value points at another `.mmt` file. Each time you read that env name, Multimeter runs the target file and uses one of its outputs. Use them when a shared value must be produced at run time — for example a fresh session id, token, or fixture — without hard-coding it in every consumer. ## How it works 1. Declare a variable whose value is a relative path to a `.mmt` file: ```yaml type: env variables: session_api: ./create_session_api.mmt session_test: ./create_session_test.mmt ``` 2. At run start, each such path becomes a **getter** in the process env store. 3. Reading `e:session_api` (or `<<e:session_api>>`) runs that file through the normal runner with **default inputs**. 4. The env value is the **first key** declared under the target’s `outputs:` (YAML order). 5. The target’s optional `cache:` controls reuse across reads in the same run. Works for any runnable type that declares `outputs:` — typically `type: api` or `type: test`. ## Target file Minimal API target — first `outputs` key is `session`: ```yaml type: api outputs: session: body.body.uuid url: https://test.mmt.dev/echo method: post format: json body: uuid: r:uuid ``` Minimal test target with a short cache window: ```yaml type: test outputs: session: '' cache: 2s steps: - set: o:session: r:uuid ``` See [cache](../test/cache.md) for duration forms (`2s`, `5m`, …). `cache:` is also allowed on API files used as live-env targets. ## Using the value Consumers reference the env name like any other variable: ```yaml type: test steps: - assert: e:session_api =* ^[0-9a-f-]{36}$ - assert: e:session_test =* ^[0-9a-f-]{36}$ ``` Or in an API body / URL: ```yaml body: api_session: e:session_api test_session: e:session_test ``` ## Environment panel In the environment variables UI, file-backed values show a clickable `(live)` chip in the value field; click it to open the target file. See [Environment variables panel](./ui.md). ## setenv vs live variables | | Live variable (`./file.mmt` in env) | `setenv` of a path string | |---|---|---| | Source | Declared under `variables:` in a `type: env` file | Written during an API/test run | | Behavior | Path becomes a getter at run start | Stays a plain path string | | Read | Each `e:name` runs the file (subject to `cache:`) | No automatic run | Only the original env copy converts `./….mmt` paths into getters. A later `setenv` of `./x.mmt` does **not** turn into a live getter. ## Example Full working sample (API + test targets, consumer test, suite): [Environment live variables](../../../examples/intermediate/32_environment_live_variables/README.md) ```sh npx testlight run examples/intermediate/32_environment_live_variables/suite.mmt \ --env-file examples/intermediate/32_environment_live_variables/multimeter.mmt ``` ## See also - [Environment overview](./index.md) - [Environment variables panel](./ui.md) - [setenv (API)](../api/setenv.md) · [setenv (test)](../test/steps/setenv.md) - [Test cache](../test/cache.md) - [Cache panel](../../panels/cache.md) — live-env TTL slots while a run is active - [Use environments](../../tasks/use-environments.md) For AI agents · llms.txt · Home