{
  "assumption_density": 0.18181818181818182,
  "assumptions": [
    "Current REST-based architecture is not experiencing measurable latency or throughput failures that block business objectives",
    "The 4 backend engineers must continue feature development alongside any migration work — migration is not their sole focus",
    "Browser clients require direct API access without additional proxy infrastructure being acceptable",
    "The 12 microservices have existing REST contracts and integration tests that would need parallel gRPC equivalents during migration",
    "No organizational mandate or external dependency forcing gRPC adoption on a fixed timeline"
  ],
  "confidence": 0.82,
  "id": "e17cddcd-a7c0-4d4a-b25a-98578c472cdf",
  "next_action": "Run a latency and payload size audit across all 12 services' inter-service REST calls for one week to identify if any specific service pair has serialization or throughput bottlenecks that would justify a targeted gRPC pilot after the 3-month window.",
  "question": "What breaks if we switch from REST to gRPC for all internal services? We have 12 microservices, 4 backend engineers, browser clients that need\n  direct API access, and a 3-month migration window.",
  "question_fit_score": 0,
  "rejected_alternatives": [
    {
      "path": "Full gRPC migration for all 12 services within 3 months",
      "rationale": "Implicit in the original question. Rejected because team size (4 engineers) and service count (12) make a clean cutover infeasible without halting feature work. Browser compatibility adds mandatory proxy infrastructure. No evidence that current REST performance is a blocking problem."
    },
    {
      "path": "Aggressive gRPC adoption arguing REST will break at scale (b004)",
      "rationale": "Branch b004 (confidence 0.40) argued REST's JSON overhead and HTTP/1.1 limitations will cause scaling problems. While directionally valid for high-throughput scenarios, it assumed scaling problems that aren't evidenced in the question, dismissed gRPC-Web proxy complexity as solvable 'in weeks' without justification, and provided no concrete latency or cost thresholds showing REST is currently failing. A reframe without actionable migration specifics."
    }
  ],
  "reversal_conditions": [
    {
      "condition": "Measured P99 inter-service latency exceeds SLA thresholds AND profiling shows JSON serialization is the dominant contributor",
      "flips_to": "Targeted gRPC migration for the specific high-latency service pairs, starting with internal-only services that don't serve browser clients"
    },
    {
      "condition": "Team grows to 8+ backend engineers AND migration window extends to 6+ months AND browser clients move behind a BFF/API gateway",
      "flips_to": "Full phased gRPC migration becomes feasible with dedicated migration squad and rollback plan per service"
    },
    {
      "condition": "New requirement for bidirectional streaming between services (e.g., real-time event processing) that REST/SSE cannot satisfy",
      "flips_to": "Adopt gRPC for streaming use cases only, keeping REST for request-response patterns (dual-protocol architecture)"
    }
  ],
  "unresolved_uncertainty": [
    "Whether any of the 12 services have latency or throughput problems that REST is actively causing — if so, selective gRPC adoption for those specific service pairs could be justified",
    "Whether the team has any existing protobuf/gRPC experience — zero experience would make even a phased migration slower than estimated",
    "Whether browser clients require real-time streaming patterns that would benefit from gRPC-Web's bidirectional streaming over REST polling/SSE"
  ],
  "url": "https://vectorcourt.com/v/e17cddcd-a7c0-4d4a-b25a-98578c472cdf",
  "verdict": "Do not switch from REST to gRPC for all internal services within the 3-month window. The core constraint is team capacity: 4 engineers migrating 12 services means each engineer owns ~3 service migrations simultaneously while maintaining existing functionality and browser client access. Browser clients cannot speak native gRPC, requiring a gRPC-Web proxy (Envoy or grpc-web) — an additional infrastructure component that must be deployed, monitored, and debugged. The critical failure mode is partial migration: services straddling both protocols double the integration surface, create contract mismatches, and force engineers to maintain two serialization paths indefinitely. If gRPC performance benefits are needed, pursue a phased approach after the 3-month window — start with a single high-traffic internal-only service pair, validate the toolchain (protobuf schema management, gRPC-Web proxy, observability integration), then expand incrementally with rollback capability at each step.",
  "verdict_core": {
    "recommendation": "Maintain the current REST architecture for all 12 internal services and do NOT attempt a full gRPC migration within the 3-month window.",
    "mechanism": "Because 4 backend engineers cannot safely migrate 12 microservices to gRPC in 3 months while maintaining browser client compatibility — gRPC lacks native browser support, requiring a gRPC-Web proxy layer that adds operational complexity, and the migration risks cascading failures across all inter-service communication during the transition period.",
    "tradeoffs": [
      "Forgo gRPC's binary serialization performance gains (typically 2-10x smaller payloads vs JSON)",
      "Remain on HTTP/1.1 semantics without HTTP/2 multiplexing benefits for inter-service calls",
      "Continue paying JSON serialization/deserialization costs across 12 services"
    ],
    "failure_modes": [
      "Partial migration leaves services straddling REST and gRPC, doubling integration surface area and debugging complexity",
      "gRPC-Web proxy becomes a single point of failure for all browser client traffic",
      "Proto schema management across 12 services overwhelms 4 engineers alongside feature work",
      "Rollback during migration causes data contract mismatches between services at different migration stages"
    ],
    "thresholds": [
      "12 microservices",
      "4 backend engineers",
      "3-month migration window"
    ]
  },
  "verdict_type": ""
}