Code Implementation (Gate 0)

Overview

This skill executes the implementation phase of the development cycle:

• Selects the appropriate specialized agent based on task content
• Applies project standards from docs/PROJECT_RULES.md
• Follows TDD methodology (RED → GREEN → REFACTOR)
• Documents implementation decisions

CRITICAL: Role Clarification

This skill ORCHESTRATES. Agents IMPLEMENT.

Step 1: Validate Input

<verify_before_proceed>

• unit_id exists
• requirements exists
• language is valid (go|typescript|python)
• service_type is valid (api|worker|batch|cli|frontend|bff) </verify_before_proceed>

REQUIRED INPUT (from ring:dev-cycle orchestrator):
- unit_id: [task/subtask being implemented]
- requirements: [acceptance criteria or task description]
- language: [go|typescript|python]
- service_type: [api|worker|batch|cli|frontend|bff]

OPTIONAL INPUT:
- technical_design: [path to design doc]
- existing_patterns: [patterns to follow]
- project_rules_path: [default: docs/PROJECT_RULES.md]

if any REQUIRED input is missing:
  → STOP and report: "Missing required input: [field]"
  → Return to orchestrator with error

Step 2: Validate Prerequisites

<block_condition>

• PROJECT_RULES.md does not exist at project_rules_path </block_condition>

If condition is true, STOP and return error to orchestrator.

1. Check PROJECT_RULES.md exists:
   Read tool → project_rules_path (default: docs/PROJECT_RULES.md)
   
   if not found:
     → STOP with blocker: "Cannot implement without project standards"
     → Return error to orchestrator

2. Select implementation agent based on language:
   
   | Language | Service Type | Agent |
   |----------|--------------|-------|
   | go | api, worker, batch, cli | ring:backend-engineer-golang |
   | typescript | api, worker | ring:backend-engineer-typescript |
   | typescript | frontend, bff | frontend-bff-engineer-typescript |
   
   Store: selected_agent = [agent name]

Step 3: Initialize Implementation State

implementation_state = {
  unit_id: [from input],
  agent: selected_agent,
  tdd_red: {
    status: "pending",
    test_file: null,
    failure_output: null
  },
  tdd_green: {
    status: "pending",
    implementation_files: [],
    pass_output: null
  },
  files_created: [],
  files_modified: [],
  commit_sha: null
}

Step 4: Gate 0.1 - TDD-RED (Write Failing Test)

<dispatch_required agent="[selected_agent]" model="opus"> Write failing test for unit_id following TDD-RED methodology. </dispatch_required>

Task:
  subagent_type: "[selected_agent]"  # e.g., "ring:backend-engineer-golang"
  model: "opus"
  description: "TDD-RED: Write failing test for [unit_id]"
  prompt: |
    ⛔ TDD-RED PHASE: Write a FAILING Test

    ## Input Context
    - **Unit ID:** [unit_id]
    - **Requirements:** [requirements]
    - **Language:** [language]
    - **Service Type:** [service_type]

    ## Project Standards
    Read and follow: [project_rules_path]

    ## Ring Standards Reference
    For Go: https://raw.githubusercontent.com/LerianStudio/ring/main/dev-team/docs/standards/golang.md
    For TS: https://raw.githubusercontent.com/LerianStudio/ring/main/dev-team/docs/standards/typescript.md

    ## Your Task
    1. Write a test that captures the expected behavior
    2. The test MUST FAIL (no implementation exists yet)
    3. Run the test and capture the FAILURE output

    ## Requirements for Test
    - Follow project naming conventions from PROJECT_RULES.md
    - Use table-driven tests (Go) or describe/it blocks (TS)
    - Test the happy path and edge cases
    - Include meaningful assertion messages

    ## Required Output Format

    ### Test File
    **Path:** [path/to/test_file]
    
    ```[language]
    [test code]
    ```

    ### Test Execution
    **Command:** [test command]
    **Result:** FAIL (expected)

    ### Failure Output (MANDATORY)
    ```
    [paste actual test failure output here]
    ```

    ⛔ HARD GATE: You MUST include actual failure output.
    Without failure output, TDD-RED is not complete.

Step 5: Validate TDD-RED Output

<block_condition>

• failure_output is missing
• failure_output does not contain "FAIL" </block_condition>

If any condition is true, re-dispatch agent with clarification.

Parse agent output:

1. Extract test file path
2. Extract failure output

if failure_output is missing or does not contain "FAIL":
  → STOP: "TDD-RED incomplete - no failure output captured"
  → Re-dispatch agent with clarification

if failure_output contains "FAIL":
  → implementation_state.tdd_red = {
      status: "completed",
      test_file: [extracted path],
      failure_output: [extracted output]
    }
  → Proceed to Step 6

Step 6: Gate 0.2 - TDD-GREEN (Implementation)

PREREQUISITE:

implementation_state.tdd_red.status == "completed"

<dispatch_required agent="[selected_agent]" model="opus"> Implement code to make test pass following TDD-GREEN methodology. </dispatch_required>

Task:
  subagent_type: "[selected_agent]"
  model: "opus"
  description: "TDD-GREEN: Implement code to pass test for [unit_id]"
  prompt: |
    ⛔ TDD-GREEN PHASE: Make the Test PASS

    ## Input Context
    - **Unit ID:** [unit_id]
    - **Requirements:** [requirements]
    - **Language:** [language]
    - **Service Type:** [service_type]

    ## TDD-RED Results (from previous phase)
    - **Test File:** [implementation_state.tdd_red.test_file]
    - **Failure Output:**
    ```
    [implementation_state.tdd_red.failure_output]
    ```

    ## Project Standards
    Read and follow: [project_rules_path]

    ## Ring Standards Reference
    For Go: https://raw.githubusercontent.com/LerianStudio/ring/main/dev-team/docs/standards/golang.md
    For TS: https://raw.githubusercontent.com/LerianStudio/ring/main/dev-team/docs/standards/typescript.md

    ## ⛔ CRITICAL: all Ring Standards Apply (no DEFERRAL)
    See Ring Standards for mandatory requirements:
    - Structured JSON logging with trace_id correlation
    - OpenTelemetry instrumentation (spans in every function)
    - Error handling (no panic, wrap with context)
    - Context propagation

    **⛔ HARD GATE:** If you output "DEFERRED" for any Ring Standard → Implementation is INCOMPLETE.

    ## Your Task
    1. Write MINIMAL code to make the test pass
    2. Follow all Ring Standards (logging, tracing, error handling)
    3. **Instrument all code with telemetry** (100% of handlers, services, repositories)
    4. Run the test and capture the PASS output

    ## ⛔ MANDATORY: Telemetry Instrumentation (NON-NEGOTIABLE)

    <cannot_skip>
    - 90%+ instrumentation coverage required
    - WebFetch standards file before implementation
    - Follow exact patterns from standards
    - Output Standards Coverage Table with evidence
    </cannot_skip>

    **every function that does work MUST be instrumented with telemetry.**
    This is not optional. This is not "nice to have". This is REQUIRED.

    ### What "Instrumented" Means
    1. **Extract logger/tracer from context** (not create new ones)
    2. **Create a child span** for the operation
    3. **Defer span.End()** immediately
    4. **Use structured logging** correlated with trace
    5. **Handle errors with span attribution** (business vs technical)

    ### Language-Specific Patterns (MANDATORY)

    **⛔ HARD GATE: Agent MUST WebFetch standards file BEFORE writing any code.**

    | Language | Standards File | REQUIRED Sections to WebFetch |
    |----------|----------------|-------------------------------|
    | **Go** | `golang.md` | "Telemetry & Observability (MANDATORY)", "Child Spans", "Context Propagation", "Anti-Patterns" |
    | **TypeScript** | `typescript.md` | "Observability", "Telemetry Patterns", "Context Propagation", "Anti-Patterns" |

    **⛔ NON-NEGOTIABLE: Agent MUST implement EXACTLY the patterns from standards. no deviations. no shortcuts.**

    | Requirement | Enforcement |
    |-------------|-------------|
    | WebFetch standards file | MANDATORY before implementation |
    | Follow exact patterns | REQUIRED - copy structure from standards |
    | Output Standards Coverage Table | REQUIRED - with file:line evidence |
    | 90%+ instrumentation coverage | HARD GATE - implementation REJECTED if below |

    ### ⛔ FORBIDDEN Patterns (HARD BLOCK)
    
    **Agent MUST WebFetch standards and check Anti-Patterns table. Violations = REJECTED.**

    - **Go:** `golang.md` → "Anti-Patterns" table - MUST check all rows
    - **TypeScript:** `typescript.md` → "Anti-Patterns" table - MUST check all rows

    **If agent uses any forbidden pattern → Implementation is INVALID. Start over.**

    ### Verification (MANDATORY)
    
    **Agent MUST output Standards Coverage Table per `standards-coverage-table.md`.**
    
    - all sections MUST show ✅ or N/A
    - any ❌ = Implementation REJECTED
    - Missing table = Implementation INCOMPLETE

    ## Required Output Format

    ### Implementation Files
    | File | Action | Lines |
    |------|--------|-------|
    | [path] | Created/Modified | +/-N |

    ### Code
    **Path:** [path/to/implementation_file]
    
    ```[language]
    [implementation code]
    ```

    ### Test Execution
    **Command:** [test command]
    **Result:** PASS

    ### Pass Output (MANDATORY)
    ```
    [paste actual test pass output here]
    ```

    ### Standards Compliance
    - Structured Logging: ✅/❌
    - OpenTelemetry Spans: ✅/❌
    - Error Handling: ✅/❌
    - Context Propagation: ✅/❌

    ### Commit
    **SHA:** [commit hash after implementation]

Step 7: Validate TDD-GREEN Output

Parse agent output:

1. Extract implementation files
2. Extract pass output
3. Extract standards compliance
4. Extract commit SHA

if pass_output is missing or does not contain "PASS":
  → STOP: "TDD-GREEN incomplete - test not passing"
  → Re-dispatch agent with error details

if any standards compliance is ❌:
  → STOP: "Standards not met - [list failing standards]"
  → Re-dispatch agent to fix

if pass_output contains "PASS" and all standards ✅:
  → implementation_state.tdd_green = {
      status: "completed",
      implementation_files: [extracted files],
      pass_output: [extracted output],
      commit_sha: [extracted SHA]
    }
  → Proceed to Step 8

Step 8: Prepare Output

Generate skill output:

## Implementation Summary
**Status:** PASS
**Unit ID:** [unit_id]
**Agent:** [selected_agent]
**Commit:** [commit_sha]

## TDD Results
| Phase | Status | Output |
|-------|--------|--------|
| RED | ✅ | [first line of failure_output] |
| GREEN | ✅ | [first line of pass_output] |

## Files Changed
| File | Action | Lines |
|------|--------|-------|
[table from implementation_files]

**Files Created:** [count]
**Files Modified:** [count]
**Tests Added:** [count]

## Standards Compliance
- Structured Logging: ✅
- OpenTelemetry Spans: ✅
- Error Handling: ✅
- Context Propagation: ✅

## Handoff to Next Gate
- Implementation status: COMPLETE
- Code compiles: ✅
- Tests pass: ✅
- Standards met: ✅
- Ready for Gate 1 (DevOps): YES
- Environment needs: [list any new deps, env vars, services]

Pressure Resistance

See shared-patterns/shared-pressure-resistance.md for universal pressure scenarios.

Anti-Rationalization Table

See shared-patterns/shared-anti-rationalization.md for universal anti-rationalizations.

Gate 0-Specific Anti-Rationalizations

Agent Selection Guide

ring:backend-engineer-golang

ring:backend-engineer-typescript

frontend-bff-engineer-typescript

ring:frontend-designer

Execution Report Format

## Implementation Summary
**Status:** [PASS|FAIL|PARTIAL]
**Unit ID:** [unit_id]
**Agent:** [agent]
**Duration:** [Xm Ys]

## TDD Results
| Phase | Status | Output |
|-------|--------|--------|
| RED | ✅/❌ | [summary] |
| GREEN | ✅/❌ | [summary] |

## Files Changed
| File | Action | Lines |
|------|--------|-------|
| [path] | [Created/Modified] | [+/-N] |

## Standards Compliance
- Structured Logging: ✅/❌
- OpenTelemetry Spans: ✅/❌
- Error Handling: ✅/❌
- Context Propagation: ✅/❌

## Handoff to Next Gate
- Implementation status: [COMPLETE|PARTIAL]
- Ready for Gate 1: [YES|no]
- Environment needs: [list]