[Bug] edit_flow / update_flow crash with "Cannot use 'in' operator to search for 'authentication'" when a Compose action's inputs is a string

[mightydadape]

Plugin

power-automate

Plugin Version

2.3.1

Skill / Command

flowagent MCP tools edit_flow and update_flow (also reproduces via preview_update → update_flow)

Bug Description

Any write to a flow that contains a Compose action whose inputs is a plain string expression (e.g. "inputs": "@body('Some_Http_Action')") fails with a TypeError before anything is written. Read tools (get_flow, preview_update, edit_flow with dryRun: true) work fine on the same flow — only the write path throws. The flow was created in the Power Automate designer; string-valued Compose inputs are the designer's normal output, so this blocks writing to a large class of existing flows.

Steps to Reproduce

1. Have an unmanaged solution cloud flow with a Compose action like:

   "My_Compose": { "type": "Compose", "inputs": "@body('Get_Data')" }

2. Call edit_flow on that flow with any operation — dryRun: true succeeds and returns a diff + previewToken.
3. Re-call edit_flow with the previewToken (or call update_flow with the full definition).

Expected Behavior

The edit is applied (with the usual auto-backup), or a validation error specific to my change.

Actual Behavior

{"code":"tool-error","message":"Cannot use 'in' operator to search for 'authentication' in @body('Get_Data')","errorName":"TypeError"}

Nothing is written. It looks like a pre-write pass iterates actions and does 'authentication' in action.inputs without first checking that inputs is an object — for Compose actions inputs is commonly a string.

Relevant Logs / Screenshots

• edit_flow (apply): {"code":"tool-error","message":"Cannot use 'in' operator to search for 'authentication' in @body('Get_Data')","errorName":"TypeError"}
• update_flow (with previewToken from preview_update): same error.
• Workaround used: updated the flow definition via the Dataverse Web API (workflow.clientdata).

Environment

• OS: macOS 15 (Darwin 25.5.0)
• Plugin: power-automate 2.3.1 (flowagent MCP server bundled with the plugin)

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🤖 This issue was created using the /report-issue skill.