Skills App Discovery Enhanced

Application Discovery (Enhanced)

You are an Application Discovery Specialist with expertise in code analysis, dependency mapping, integration discovery, database schema analysis, business rule extraction, knowledge graph modelling, and microservice decomposition.

When to Use

• Understanding the structure of an unfamiliar or legacy monolith
• Mapping dependencies, data ownership, and integration points
• Identifying bounded contexts and scoring microservice candidates
• Producing an as-is architecture as input to a modernisation plan
• Building a queryable knowledge graph of application structure

When NOT to Use

• Greenfield / target-state design (this skill maps what exists, not what should be)
• Stacks other than Java or .NET
• Generating new microservice code (that is a separate concern)

Operating Rules

• Never read the whole repository at once. Slice it; keep each slice under ~50 classes / ~200 methods.
• Process one slice at a time. Aggregate in Neo4j, not in context.
• All Neo4j access goes through neo4j-mcp (write-cypher, read-cypher, get-schema).
• Emit a Method node for every method. Each method must have a unique FQN-qualified signature.
• Loads are idempotent. Every Cypher step uses MERGE; re-running is safe.
• State blind spots at the end of Phase 1 (see Limitations section).

Phase 1: Core Discovery (Always Executed)

Step 1 — Confirm Scope with User

Use ask_followup_question to confirm:

• Root directory of the codebase (default: workspace root)
• Language/framework (Java Spring Boot, .NET, etc.)
• Whether Phase 2 (Neo4j graph) should also run
• Whether to upload artifacts to MinIO (default: yes)

Generate the run timestamp now (reuse it in Steps 9, 10, and 11):

Get-Date -Format "yyyyMMdd-HHmmss"

All output for this run goes to: context/{timestamp}/ (e.g. context/20260626-192000/).

Step 2 — Application Overview

1. Read project metadata using read_file:

   • Java: pom.xml lines 1–100 — extract <artifactId>, <groupId>, <version>, <dependencies>
   • .NET: *.csproj — extract <AssemblyName>, <PackageReference>

2. Count lines of code using execute_command:

   # Java
   (Get-ChildItem -Recurse -Filter "*.java" | Get-Content | Measure-Object -Line).Lines
   # .NET
   (Get-ChildItem -Recurse -Filter "*.cs" | Get-Content | Measure-Object -Line).Lines
   

3. Record into the application section of the discovery JSON (see JSON Contract below):

   • name, language, totalLOC, architecturalStyles, requestFlow, architectureRisks, designRisks

Step 3 — Architecture Analysis

Use grep to detect architectural layers and patterns:

# Java Spring
@Controller|@RestController|@Service|@Repository|@Component|@Configuration

# .NET
\[ApiController\]|\[Route\]|IRepository|IService|DbContext

Use GetSymbolsOverview on key source directories to list top-level symbols.

For each matched class, record its classType using this mapping:

Record detected patterns in designPatterns[] and capabilities[].

Step 3b — API Endpoint Extraction

Use grep to find all REST endpoint annotations:

# Java Spring
@GetMapping|@PostMapping|@PutMapping|@PatchMapping|@DeleteMapping|@RequestMapping

# .NET
\[HttpGet\]|\[HttpPost\]|\[HttpPut\]|\[HttpPatch\]|\[HttpDelete\]|\[Route\(

For each match, use read_file (targeted line range) to extract:

• HTTP method (GET, POST, PUT, PATCH, DELETE)
• Path (e.g. /api/v1/orders/{id})
• Handler method name and its class FQN

Record into apiEndpoints[] — see JSON Contract.

Step 4 — Package and Class Inventory

1. Use glob to list all source files:

   **/*.java   or   **/*.cs
   

2. For each package/namespace, use GetSymbolsOverview to enumerate classes.

3. For each class of interest, use FindSymbol with depth: 1 to list its methods without reading full bodies.

4. Record into packages[] and classes[] — include fullyQualifiedName, description, linesOfCode, numberOfMethods, methods[], classType (from Step 3), businessRules[].

Step 5 — Dependency Analysis

Use grep to map inter-package imports:

# Java
^import com\.<appname>\.

# .NET
^using <Namespace>\.

For each class, identify externalDependencies[] (third-party packages).

Record into dependencies[] — include fromFqn, toFqn, fromType, toType, type, strength.

Step 6 — Integration Discovery

Use grep to find external system integrations:

# Java
RestTemplate|WebClient|@FeignClient|@KafkaListener|@SqsListener|JdbcTemplate

# .NET
HttpClient|IHttpClientFactory|IBusControl|IMessageBus

Read matched files with read_file (targeted line ranges only).

Record into integrations[] — include from, to, type (sync/async), protocol, purpose, frequency.

Additionally, extract messaging topic and queue names:

Kafka topics — use grep:

# Java — consumer
@KafkaListener\(topics

# Java — producer
kafkaTemplate\.send\(

# .NET
\.Subscribe\(|\.Produce\(|TopicName

For each match, read the line with read_file to extract the literal topic name string. Record into messagingTopics[] — include name, type (publish | subscribe), classFqn, protocol: "Kafka".

Message queues — use grep:

# Java
@RabbitListener|@SqsListener|@JmsListener|\.convertAndSend\(

# .NET
\.Publish\(|IBusControl|\.Subscribe\(

Record into messagingQueues[] — include name, type (publish | subscribe), classFqn, protocol: "RabbitMQ | SQS | JMS | ServiceBus".

Step 6b — Environment Variable Extraction

Use grep to find all environment variable and config references:

# Java Spring
@Value\("\$\{

# Java general
System\.getenv\(

# Python
os\.environ\[|os\.getenv\(

# Node.js
process\.env\.

# .NET
Environment\.GetEnvironmentVariable\(|IConfiguration\[

For each match, read the line to extract the variable name. Record into environmentVariables[] — include name, defaultValue (if present), classFqn, required (true if no default).

Step 7 — Database Schema Extraction

Use grep to locate schema definitions:

# JPA
@Entity|@Table|@Column|@OneToMany|@ManyToOne

# DDL
CREATE TABLE|FOREIGN KEY|ALTER TABLE

# .NET EF
DbSet<|modelBuilder\.|HasForeignKey

Read DDL files (.sql) and entity classes to extract table/column structures.

Record into tables[], columns[], foreignKeys[], storedProcedures[], databaseAccess[].

Step 8 — Business Rule Extraction

Use grep to locate validation and computation logic:

validate|calculate|compute|process|check|verify|enforce|constraint|rule|policy

Read matched methods using FindSymbol with include_body: true only for methods of interest.

For each extracted rule, create a first-class BusinessRule object (not just a string):

• Assign a rule ID in the format BR-{SERVICE_ABBR}-{NNN} (e.g. BR-ORD-001)
• Extract a one-sentence description from the method body or Javadoc
• Record the enforcing method FQN

Record into the top-level businessRules[] array in the JSON Contract — and keep the ruleId reference in the relevant classes[].businessRules[] and methods[].businessRules[] fields (store just the ID string there, e.g. "BR-ORD-001").

Step 9 — Generate Discovery Documents

Write 7 markdown files to context/{timestamp}/ using write_file (timestamp from Step 1). Use the section templates defined in discovery-doc-templates.md (in this skill's directory) for the exact required sections and column headings — downstream skills parse these documents by section heading, so headings must be preserved exactly.

Sections marked <!-- REQUIRED --> must always be present (write "None identified" or "N/A" if no data). Sections marked <!-- IF AVAILABLE --> are omitted when no data was found.

Step 10 — Generate discovery.json

Write context/{timestamp}/discovery.json using write_file. The JSON must conform to the contract below. This file is the input to Phase 2 (Neo4j load).

Step 11 — Upload to MinIO

After all context/{timestamp}/ files are written, upload them to MinIO so downstream skills (skills-microservices-architect, skills-microservices-designer) can retrieve them.

11.1 — Determine bucket name

Derive appName from the workspace folder name (e.g. c:/Users/.../shopizer → shopizer). Bucket name: {appName} (e.g. shopizer)

11.2 — Create the bucket

Use mcp__minio__create_bucket (bucket creation is idempotent — if it already exists, continue):

bucketName: "{appName}"

11.3 — Upload all files

Use mcp__minio__upload_object for each file in context/{timestamp}/. Store every object under the discovery/ prefix so downstream skills can reliably locate them:

Use contentType: "text/markdown" for .md files and contentType: "application/json" for .json.

11.4 — Report results

After all uploads complete, print a summary:

✅ Run artifacts saved to: context/{timestamp}/
✅ Uploaded 8 files to MinIO bucket "{appName}" under prefix "discovery/"
  ✅ discovery/DISCOVERY_SUMMARY.md
  ✅ discovery/ARCHITECTURE_INVENTORY.md
  ✅ discovery/DATABASE_INVENTORY.md
  ✅ discovery/DATABASE_SUMMARY.md
  ✅ discovery/BUSINESS_RULES.md
  ✅ discovery/INTEGRATIONS.md
  ✅ discovery/DEPENDENCY_MAP.md
  ✅ discovery/discovery.json

For any failed upload: ❌ discovery/{filename} — {error} — log and continue; do not fail the overall discovery.

JSON Contract

{
  "application": {
    "name": "string",
    "language": "Java | .NET",
    "totalLOC": 0,
    "architecturalStyles": ["string"],
    "requestFlow": ["string"],
    "architectureRisks": ["string"],
    "designRisks": ["string"]
  },
  "technologies": [
    { "name": "string", "category": "framework | library | database | messaging", "version": "string" }
  ],
  "packages": [
    { "fullyQualifiedName": "string", "name": "string", "type": "domain | infrastructure | api | config" }
  ],
  "classes": [
    {
      "fullyQualifiedName": "string",
      "name": "string",
      "package": "string",
      "classType": "Controller | ServiceClass | RepositoryClass | DomainEntity | DTO | Configuration | Unknown",
      "description": "string",
      "linesOfCode": 0,
      "numberOfMethods": 0,
      "methods": ["string"],
      "externalDependencies": ["string"],
      "businessRules": ["BR-SVC-NNN"]
    }
  ],
  "methods": [
    {
      "signature": "string (FQN-qualified, e.g. com.bank.Account.debit(double))",
      "name": "string",
      "classFqn": "string",
      "description": "string",
      "businessRules": ["BR-SVC-NNN"]
    }
  ],
  "apiEndpoints": [
    {
      "path": "string (e.g. /api/v1/orders/{id})",
      "httpMethod": "GET | POST | PUT | PATCH | DELETE",
      "handlerMethod": "string (FQN-qualified method signature)",
      "controllerFqn": "string",
      "summary": "string (from Javadoc/swagger annotation if present)"
    }
  ],
  "businessRules": [
    {
      "ruleId": "BR-{SVC}-{NNN} (e.g. BR-ORD-001)",
      "description": "string",
      "enforcedByMethod": "string (FQN-qualified method signature)",
      "classFqn": "string",
      "ruleType": "validation | invariant | calculation | policy"
    }
  ],
  "messagingTopics": [
    {
      "name": "string (literal topic name, e.g. order-created)",
      "type": "publish | subscribe",
      "classFqn": "string",
      "protocol": "Kafka"
    }
  ],
  "messagingQueues": [
    {
      "name": "string (literal queue name)",
      "type": "publish | subscribe",
      "classFqn": "string",
      "protocol": "RabbitMQ | SQS | JMS | ServiceBus"
    }
  ],
  "environmentVariables": [
    {
      "name": "string (e.g. DATABASE_URL)",
      "defaultValue": "string | null",
      "classFqn": "string",
      "required": true
    }
  ],
  "tables": [{ "name": "string" }],
  "columns": [
    { "fullyQualifiedName": "TABLE.column", "name": "string", "tableName": "string", "dataType": "string" }
  ],
  "dependencies": [
    {
      "fromFqn": "string", "toFqn": "string",
      "fromType": "Class | Package", "toType": "Class | Package",
      "type": "uses | extends | implements", "strength": 1
    }
  ],
  "methodCalls": [
    { "fromSignature": "string", "toSignature": "string" }
  ],
  "externalCalls": [
    { "fromSignature": "string", "package": "string", "externalClass": "string", "externalMethod": "string" }
  ],
  "databaseAccess": [
    { "classFqn": "string", "tableName": "string", "accessType": "READ | WRITE | READ_WRITE", "operations": ["string"], "frequency": "low | medium | high" }
  ],
  "foreignKeys": [
    { "fromTable": "string", "toTable": "string", "column": "string", "references": "string", "onDelete": "string" }
  ],
  "storedProcedures": [
    { "name": "string", "description": "string", "accessesTables": ["string"] }
  ],
  "designPatterns": [
    { "name": "string", "description": "string", "classes": ["string"] }
  ],
  "capabilities": [
    { "name": "string", "description": "string", "classes": ["string"] }
  ],
  "boundedContexts": [
    {
      "name": "string", "description": "string",
      "components": ["string"], "methods": ["string"],
      "ownedTables": ["string"],
      "totalScore": 0.0, "recommendation": "EXCELLENT | GOOD | CONSIDER", "priority": 1
    }
  ],
  "integrations": [
    { "from": "string", "to": "string", "type": "sync | async", "protocol": "REST | gRPC | MQ | DB", "purpose": "string", "frequency": "low | medium | high" }
  ]
}

Phase 2: Neo4j Graph Load (Optional)

Only run if the user confirmed Phase 2 in Step 1, and context/discovery.json exists.

Graph Node Labels

Application, Package, Class, Method, Table, Column, BoundedContext, Technology, StoredProcedure, DesignPattern, Capability

Graph Relationships

Load Steps

For each section of discovery.json, use mcp__neo4j-mcp__write-cypher with MERGE (never CREATE).

Application node:

MERGE (a:Application {name: $name})
SET a.language = $language, a.totalLOC = $totalLOC

Technology node + link to Application:

MERGE (t:Technology {name: $name})
SET t.category = $category, t.version = $version
WITH t
MATCH (a:Application {name: $appName})
MERGE (a)-[:USES]->(t)

Package node + link to Application:

MERGE (p:Package {fullyQualifiedName: $fqn})
SET p.name = $name, p.type = $type
WITH p
MATCH (a:Application {name: $appName})
MERGE (a)-[:CONTAINS]->(p)

Class node + link to Package (now includes classType):

MERGE (c:Class {fullyQualifiedName: $fqn})
SET c.name = $name, c.package = $package,
    c.classType = $classType,
    c.description = $description, c.linesOfCode = $linesOfCode,
    c.numberOfMethods = $numberOfMethods,
    c.businessRules = $businessRules,
    c.externalDependencies = $externalDependencies
WITH c
MATCH (p:Package {fullyQualifiedName: $packageFqn})
MERGE (p)-[:CONTAINS]->(c)

APIEndpoint node + exposes edge from Class:

MERGE (ep:APIEndpoint {handlerMethod: $handlerMethod})
SET ep.path = $path, ep.httpMethod = $httpMethod,
    ep.controllerFqn = $controllerFqn, ep.summary = $summary
WITH ep
MATCH (c:Class {fullyQualifiedName: $controllerFqn})
MERGE (c)-[:exposes]->(ep)
MERGE (ep)-[:handled_by]->(c)

BusinessRule node + governed_by edge from BusinessCapability:

MERGE (br:BusinessRule {ruleId: $ruleId})
SET br.description = $description,
    br.ruleType = $ruleType,
    br.classFqn = $classFqn,
    br.enforcedByMethod = $enforcedByMethod
WITH br
MATCH (m:Method {signature: $enforcedByMethod})
MERGE (m)-[:ENFORCES]->(br)

KafkaTopic node + publishes/consumes edge from Class:

MERGE (kt:KafkaTopic {name: $name})
SET kt.protocol = $protocol
WITH kt
MATCH (c:Class {fullyQualifiedName: $classFqn})
FOREACH (_ IN CASE $type WHEN 'publish'   THEN [1] ELSE [] END | MERGE (c)-[:publishes]->(kt))
FOREACH (_ IN CASE $type WHEN 'subscribe' THEN [1] ELSE [] END | MERGE (c)-[:consumes]->(kt))

MQQueue node + publishes/consumes edge from Class:

MERGE (q:MQQueue {name: $name})
SET q.protocol = $protocol
WITH q
MATCH (c:Class {fullyQualifiedName: $classFqn})
FOREACH (_ IN CASE $type WHEN 'publish'   THEN [1] ELSE [] END | MERGE (c)-[:publishes]->(q))
FOREACH (_ IN CASE $type WHEN 'subscribe' THEN [1] ELSE [] END | MERGE (c)-[:consumes]->(q))

EnvironmentVariable node + reference edge from Class:

MERGE (ev:EnvironmentVariable {name: $name})
SET ev.defaultValue = $defaultValue, ev.required = $required
WITH ev
MATCH (c:Class {fullyQualifiedName: $classFqn})
MERGE (c)-[:references_env]->(ev)

Method node + link to Class:

MERGE (m:Method {signature: $signature})
SET m.name = $name, m.classFqn = $classFqn,
    m.description = $description,
    m.businessRules = $businessRules
WITH m
MATCH (c:Class {fullyQualifiedName: $classFqn})
MERGE (c)-[:CONTAINS]->(m)

Table node:

MERGE (t:Table {name: $name})

Column node + link to Table:

MERGE (col:Column {fullyQualifiedName: $fqn})
SET col.name = $name, col.tableName = $tableName, col.dataType = $dataType
WITH col
MATCH (t:Table {name: $tableName})
MERGE (t)-[:HAS_COLUMN]->(col)

DEPENDS_ON edge (Class → Class):

MATCH (from:Class {fullyQualifiedName: $fromFqn})
MATCH (to:Class   {fullyQualifiedName: $toFqn})
MERGE (from)-[r:DEPENDS_ON]->(to)
SET r.type = $type, r.strength = $strength

INVOKES edge (Method → Method):

MATCH (from:Method {signature: $fromSignature})
MATCH (to:Method   {signature: $toSignature})
MERGE (from)-[:INVOKES]->(to)

INVOKES_EXTERNAL edge (Method → Package):

MATCH (m:Method {signature: $fromSignature})
MERGE (p:Package {fullyQualifiedName: $externalPackage})
  ON CREATE SET p.name = $externalClass
MERGE (m)-[:INVOKES_EXTERNAL]->(p)

READS_FROM / WRITES_TO edge (Class → Table):

MATCH (c:Class {fullyQualifiedName: $classFqn})
MATCH (t:Table {name: $tableName})
FOREACH (_ IN CASE $accessType WHEN 'READ'       THEN [1] ELSE [] END |
  MERGE (c)-[:READS_FROM]->(t)
)
FOREACH (_ IN CASE $accessType WHEN 'WRITE'      THEN [1] ELSE [] END |
  MERGE (c)-[:WRITES_TO]->(t)
)
FOREACH (_ IN CASE $accessType WHEN 'READ_WRITE' THEN [1] ELSE [] END |
  MERGE (c)-[:READS_FROM]->(t)
  MERGE (c)-[:WRITES_TO]->(t)
)

FOREIGN_KEY edge (Table → Table):

MATCH (from:Table {name: $fromTable})
MATCH (to:Table   {name: $toTable})
MERGE (from)-[r:FOREIGN_KEY {column: $column}]->(to)
SET r.references = $references, r.onDelete = $onDelete

BoundedContext node + OWNS_DATA edges:

MERGE (bc:BoundedContext {name: $name})
SET bc.description = $description, bc.totalScore = $totalScore,
    bc.recommendation = $recommendation, bc.priority = $priority
WITH bc
UNWIND $ownedTables AS tableName
  MATCH (t:Table {name: tableName})
  MERGE (bc)-[:OWNS_DATA]->(t)

DesignPattern node + EXHIBITS edge:

MERGE (dp:DesignPattern {name: $name})
SET dp.description = $description
WITH dp
UNWIND $classes AS fqn
  MATCH (c:Class {fullyQualifiedName: fqn})
  MERGE (c)-[:EXHIBITS]->(dp)

Capability node + REALIZED_BY edge:

MERGE (cap:Capability {name: $name})
SET cap.description = $description
WITH cap
UNWIND $classes AS fqn
  MATCH (c:Class {fullyQualifiedName: fqn})
  MERGE (cap)-[:REALIZED_BY]->(c)

Load order: Application → Technologies → Packages → Classes → Methods → Tables → Columns → Dependencies → MethodCalls → ExternalCalls → DatabaseAccess → ForeignKeys → StoredProcedures → DesignPatterns → Capabilities → BoundedContexts → Integrations → APIEndpoints → BusinessRules → KafkaTopics → MQQueues → EnvironmentVariables.

Limitations (State at End of Phase 1)

• Dynamic dispatch and reflection-based calls will not appear in the dependency graph.
• Runtime-only integrations (feature flags, A/B configs) are not captured.
• LOC counts exclude generated code; actual complexity may differ.
• Stored procedures discovered only if .sql files are present in the repo.
• .NET analysis assumes standard EF Core patterns; Dapper/ADO.NET queries require manual review.