Status Summary
The Sample App's start_workflow MCP tool accepts ordered PHP workflow arguments, but its published tool schema declares every arguments array item as a string. The sandbox workflow exposed at sample-app:main commit 45f68b9e876a5094c61f2f1f393e8923820e7262 requires its first argument to be an array of {type, args} tool-call objects.
A schema-conforming MCP client therefore cannot construct the documented sandbox request: the advertised schema rejects the structured value that the handler requires. Current sandbox boundary coverage invokes the tool handler with nested arrays directly and does not validate the public tools/list schema against that request.
How to fix
Make the ordered-argument schema truthfully admit the JSON value shapes supported by workflow handlers, including arrays, objects, strings, numbers, booleans, and null where applicable. Keep runtime argument-count boundaries intact. Add protocol-level coverage that obtains the published tool schema, validates a real structured sandbox start request against it, calls start_workflow, and proves the workflow is accepted without bypassing the MCP contract.
Delete when
A conforming MCP client can validate and submit the configured sandbox workflow's structured tool-call argument using the published start_workflow schema, and tests protect both schema truthfulness and runtime argument limits.
Status Summary
The Sample App's
start_workflowMCP tool accepts ordered PHP workflow arguments, but its published tool schema declares everyargumentsarray item as a string. The sandbox workflow exposed atsample-app:maincommit45f68b9e876a5094c61f2f1f393e8923820e7262requires its first argument to be an array of{type, args}tool-call objects.A schema-conforming MCP client therefore cannot construct the documented sandbox request: the advertised schema rejects the structured value that the handler requires. Current sandbox boundary coverage invokes the tool handler with nested arrays directly and does not validate the public
tools/listschema against that request.How to fix
Make the ordered-argument schema truthfully admit the JSON value shapes supported by workflow handlers, including arrays, objects, strings, numbers, booleans, and null where applicable. Keep runtime argument-count boundaries intact. Add protocol-level coverage that obtains the published tool schema, validates a real structured sandbox start request against it, calls
start_workflow, and proves the workflow is accepted without bypassing the MCP contract.Delete when
A conforming MCP client can validate and submit the configured sandbox workflow's structured tool-call argument using the published
start_workflowschema, and tests protect both schema truthfulness and runtime argument limits.