# Invoke Lambda function synchronously

Canonical URL: https://docs.fuse.init.inc/integrations/aws/actions/lambda.functions.invoke_sync

Invoke a Lambda function with RequestResponse semantics and a 15-second abort. Payload is JSON text capped at 256 KiB by this pack. Returns status, executed version, function error, base64 payload, optional decoded JSON text, and optional log tail. Unsafe with one SDK attempt. Excluded from MCP. Requires lambda:InvokeFunction.

Action ID: `lambda.functions.invoke_sync`
Provider: AWS (`aws`)
Contract version: 1

## Risk and exposure

- Risk: Write
- Idempotency: Unsafe — Retries may duplicate side effects; callers must coordinate carefully.
- Availability: Default
- Exposure: REST, SDK
- MCP hints: readOnly=false, destructive=false, idempotent=false, openWorld=true

## Required scopes

- `lambda:InvokeFunction`

## Input schema fields

- `function_name`
- `payload`
- `region`
- `qualifier`
- `include_log_tail`

## Output schema fields

- `status_code`
- `executed_version`
- `function_error`
- `payload_base64`
- `payload_json`
- `log_tail`

Provider overview: https://docs.fuse.init.inc/integrations/aws
Actions index: https://docs.fuse.init.inc/integrations/aws/actions
Exact canonical JSON contract: https://docs.fuse.init.inc/api/catalog/v1/providers/aws/actions/lambda.functions.invoke_sync
Deployment-effective discovery: https://api.fuse.init.inc/v1/tenants/%7Btenant_id%7D/providers/aws/actions