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Logging

Mastra’s logging system captures function execution, input data, and output responses in a structured format.

When deploying to Mastra Cloud, logs are shown on the Logs page. In self-hosted or custom environments, logs can be directed to files or external services depending on the configured transports.

PinoLogger

When initializing a new Mastra project using the CLI, PinoLogger is included by default.

src/mastra/index.ts
import { Mastra } from '@mastra/core/mastra'; import { PinoLogger } from '@mastra/loggers'; export const mastra = new Mastra({ // ... logger: new PinoLogger({ name: 'Mastra', level: 'info', }), });

See the PinoLogger API reference for all available configuration options.

Logging from workflows and tools

Mastra provides access to a logger instance via the mastra.getLogger() method, available inside both workflow steps and tools. The logger supports standard severity levels: debug, info, warn, and error.

Logging from workflow steps

Within a workflow step, access the logger via the mastra parameter inside the execute function. This allows you to log messages relevant to the step’s execution.

src/mastra/workflows/test-workflow.ts
import { createWorkflow, createStep } from "@mastra/core/workflows"; import { z } from "zod"; const step1 = createStep({ //... execute: async ({ mastra }) => { const logger = mastra.getLogger(); logger.info("workflow info log"); return { output: "" }; } }); export const testWorkflow = createWorkflow({...}) .then(step1) .commit();

Logging from tools

Similarly, tools have access to the logger instance via the mastra parameter. Use this to log tool specific activity during execution.

src/mastra/tools/test-tool.ts
import { createTool } from "@mastra/core/tools"; import { z } from "zod"; export const testTool = createTool({ // ... execute: async ({ mastra }) => { const logger = mastra?.getLogger(); logger?.info("tool info log"); return { output: "" }; } });

Logging with additional data

Logger methods accept an optional second argument for additional data. This can be any value, such as an object, string, or number.

In this example, the log message includes an object with a key of agent and a value of the testAgent instance.

src/mastra/workflows/test-workflow.ts
import { createWorkflow, createStep } from "@mastra/core/workflows"; import { z } from "zod"; const step1 = createStep({ //... execute: async ({ mastra }) => { const testAgent = mastra.getAgent("testAgent"); const logger = mastra.getLogger(); logger.info("workflow info log", { agent: testAgent }); return { output: "" }; } }); export const testWorkflow = createWorkflow({...}) .then(step1) .commit();