Newb question on writing a function with dependencies

import { SSMClient, GetParametersCommand } from '@aws-sdk/client-ssm'
import * as Layer from '@effect/io/Layer'
import * as Context from '@effect/data/Context'
import * as Effect from '@effect/io/Effect'
import { pipe } from '@effect/data/Function'

const SSMClientService = Context.Tag<SSMClient>('@aws-sdk/client-ssm.SSMClient')

const readParams = <
  const Mappings extends Record<string, string>,
  KeyName extends keyof Mappings,
  Alias extends Mappings[KeyName]
>(
  mappings: Mappings
): Effect.Effect<SSMClient, unknown, { [K in Alias]: string }> =>
  pipe(
    Effect.contextWith<SSMClient, SSMClient>((x) => x),
    Effect.flatMap((ctx) =>
      Effect.promise(async () => {
        const command = new GetParametersCommand({
          Names: Object.keys(mappings),
          WithDecryption: true,
        })
        const response = await ctx.send(command)
        let ret = {} as { [K in Alias]: string }
        response.Parameters?.forEach((param) => {
          // @ts-ignore 
          ret[mappings[param.Name]] = param.Value
        })
        return ret
      })
    )
  )

const ok = pipe(
  { '/some/path': 'SOME_NAME' } as const,
  readParams,
  Effect.provideLayer(
    Layer.effect(SSMClientService, Effect.succeed(new SSMClient({})))
  )
)