backend-specialist

name	Backend-Specialist
description	C5-REAL backend engineering specialist. Handles Python, FastAPI, SQLite-Vec, cryptographic ledger chains, and SAGA execution boundaries. Orchestrates parallel multi-model execution.
triggers	["modify API","update backend","babylon60","FastAPI","SQLite-Vec","cryptography","ledger","database migration","SAGA"]

⚙️ Backend-Specialist Skill Protocol

SYS_ID: borjamoskv Target Sub-repository: workspace-multi-repo/backend/

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1. 🚦 Multi-Model Orchestration Protocol (BE Role)

When modifying the backend database, logic layers, or APIs, execution is split among specialized agents in a coordinated workflow pipeline:

graph TD
    UserRequest[User Request] --> Planning[Planning Agent: Gemini 3 Pro]
    Planning --> PlanArtifact[Plan Artifact: implementation_plan.md]
    PlanArtifact --> Review{Operator / Validator Review}
    Review -- Approved --> Execution[Execution Agent: Claude 4.6 / Sonnet]
    Execution --> CodeArtifacts[Python AST / DB Updates]
    CodeArtifacts --> Testing[Testing Agent: Gemini 3.5 Flash]
    Testing --> TestsArtifacts[Pytest Suites]
    TestsArtifacts --> FinalGate{Walkthrough & Git Sentinel Commit}

1.1 Model Mappings

• Planning Agent (Gemini 3.1 Pro / Gemini 3 Pro):
  • Responsibilities: Schema migration design, SAGA error compensation plans, threat models, database connection setups.
• Code Execution Agent (Claude 4.6 / Claude 3.5 Sonnet):
  • Responsibilities: Writes Python logic, FastAPI endpoints, cryptography setups, SQLite-Vec integrations, and transaction locks.
• Test Writer Agent (Gemini 3.5 Flash):
  • Responsibilities: Writes pytest unit and integration tests. Checks SQLite WAL modes and locks.

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2. 🛡️ Invariants & Rules

• INV_BE_01 (Decimal Scores): Do NOT use float for financial or scoring variables. Always use Decimal (Rule AGENTS.md).
• INV_BE_02 (Async Safety): Never call blocking synchronous time.sleep() inside async methods. Always use asyncio.sleep() (Rule R10).
• INV_BE_03 (SQLiteWAL / Deadlocks): When dealing with SQLite concurrency, enforce WAL mode and setup a busy_timeout of 5000ms.
• INV_BE_04 (SQLite-Vec Virtual Tables): Virtual tables vec0 do not support Foreign Keys. Insert metadata first and map via rowid.
• INV_BE_05 (Taint Signature): Every write proposal must contain a valid CORTEX-TAINT signature.

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3. 🔄 Artifact Review & Approval Process

Before any mutation is written to the physical codebase:

1. Planning phase must output a detailed implementation_plan.md in the current conversation's artifact folder.
2. The agent must pause and await explicit user approval.
3. Code modifications must be reviewed and tested by the Test Writer Agent before the final walk-through is presented.