Case Study 03: CodeExplorer vs codebase-memory-mcp (CBM).

# C1: Incoming HTTP / GraphQL / FastAPI Endpoints
# CodeExplorer (ce):
MATCH (e:Endpoint)-[:EXPOSED_BY]->(f:Function)
RETURN f.file_path, f.start_line, f.name, e.http_method, e.route_template

# codebase-memory-mcp (CBM):
MATCH (m)-[:HANDLES]->(r:Route)
RETURN m.file_path, m.start_line, m.name, r.name

# ------------------------------------------------------------------------------
# C2: Outbound Inter-Service & External HTTP Calls
# CodeExplorer (ce):
MATCH (ext:ExternalService)-[r:CALLED_BY]->(f:Function)
WHERE COALESCE(ext.protocol, 'http') <> 'graphql'
RETURN f.file_path, COALESCE(r.line, f.start_line), f.name, COALESCE(ext.url, ext.name);

MATCH (f:Function)-[r:CALLS_ENDPOINT]->(ep:Endpoint)
WHERE COALESCE(ep.protocol, 'REST') <> 'GraphQL'
RETURN f.file_path, COALESCE(r.line, f.start_line), f.name, COALESCE(ep.route_template, ep.name);

# codebase-memory-mcp (CBM):
MATCH (a)-[:HTTP_CALLS]->(b)
RETURN a.file_path, a.start_line, a.name, b.name

# ------------------------------------------------------------------------------
# C6: Call Graph (Direct & DI Service Method Callers)
# CodeExplorer (ce):
MATCH (caller:Function)-[:CALLS]->(callee:Function)
WHERE callee.name IN [<target_methods>]
OPTIONAL MATCH (enclosing:Function)-[:DECLARES]->(caller)
RETURN caller.file_path, COALESCE(enclosing.start_line, caller.start_line), COALESCE(enclosing.name, caller.name), callee.name

# codebase-memory-mcp (CBM):
MATCH (caller)-[:CALLS]->(callee)
WHERE callee.name = '<target_method>'
RETURN caller.file_path, caller.start_line, caller.name, callee.name

# ------------------------------------------------------------------------------
# C7: Class Inheritance & Interface Implementation
# CodeExplorer (ce):
MATCH (c:Type)-[r:INHERITS_FROM|IMPLEMENTS]->(p)
RETURN c.file_path, c.start_line, c.name, type(r), p.name

# codebase-memory-mcp (CBM):
MATCH (c)-[r:INHERITS|IMPLEMENTS]->(p)
RETURN c.file_path, c.start_line, c.name, type(r), p.name

# C3 & C8: Message Queue Producers & Consumers (BullMQ / @OnJob)
MATCH (t:Topic)-[:PUBLISHED_BY]->(f:Function)
RETURN f.file_path, f.start_line, f.name, t.name;

MATCH (t:Topic)-[:SUBSCRIBED_BY]->(m:Function)
RETURN m.file_path, m.start_line, m.name, t.name;

# C4 & C10: Database Tables, Entities & Schema Members
MATCH (t:Table) OPTIONAL MATCH (t)-[:IMPLEMENTED_BY]->(ent:Type)
RETURN COALESCE(ent.file_path, t.path), ent.start_line, COALESCE(ent.name, t.name), t.name;

MATCH (t:Table)-[:IMPLEMENTED_BY]->(ent:Type)-[:HAS_MEMBER]->(m:Member)
RETURN ent.file_path, m.start_line, m.name, t.name;

# C5: Code-to-Table Read/Write Lineage (TypeORM & Kysely)
MATCH (q:Query)-[r:WRITES_TO|READS_FROM]->(t:Table)
OPTIONAL MATCH (q)-[:ACCESSED_BY]->(f:Function)
RETURN COALESCE(f.file_path, q.file_path), q.start_line, COALESCE(f.name, q.name), type(r), t.name;

# C9: Monorepo Services & Sub-Projects
MATCH (p:Project) RETURN p.path, labels(p), p.name;

# C11: 6 End-to-End Architectural Queries (Single-Query Expressibility)
# Q1 — Topics with producers but no consumers (or vice versa):
MATCH (t:Topic) WHERE NOT (t)-[:SUBSCRIBED_BY]->() OR NOT (t)-[:PUBLISHED_BY]->() RETURN t.name
# Q2 — Pairs of projects sharing a database:
MATCH (p1:Project)-[:USES_DB]->(d:Database)<-[:USES_DB]-(p2:Project) WHERE p1.name < p2.name RETURN p1.name, p2.name, d.name
# Q3 — Top written database tables:
MATCH (q:Query)-[:WRITES_TO]->(t:Table) RETURN t.name, count(q) AS writes ORDER BY writes DESC LIMIT 10
# Q4 — Endpoints transitively writing to a database table within 1..4 call hops:
MATCH (e:Endpoint)-[:EXPOSED_BY]->(f:Function)-[:CALLS*1..4]->(w:Function)<-[:DECLARED_IN]-(q:Query)-[:WRITES_TO]->(t:Table) RETURN e.name, t.name LIMIT 20
# Q5 — Per-project endpoint and published topic counts:
MATCH (p:Project) OPTIONAL MATCH (p)-[:EXPOSES]->(e:Endpoint) OPTIONAL MATCH (p)-[:PUBLISHES_TO]->(tp:Topic) RETURN p.name, count(DISTINCT e), count(DISTINCT tp)
# Q6 — End-to-end chain: Endpoint -> Call Chain (0..3 hops) -> Queue Publish -> Queue Subscriber:
MATCH (e:Endpoint)-[:EXPOSED_BY]->(f:Function)-[:CALLS*0..3]->(pub:Function)<-[:PUBLISHED_BY]-(t:Topic)-[:SUBSCRIBED_BY]->(sub) RETURN e.name, t.name, sub.name LIMIT 20

All patterns were verified against real source files in `twentyhq/twenty` (`12e8fae471865e9dab60c0b0fd59f318505c804e`) and `immich-app/immich` (`2153d22f34349de690cd98890ee4c635808da638`). Test files (`*.spec.ts`, `*.test.ts`, `__tests__`, `test/`, `e2e/`, `fixtures/`, `test_*.py`) are excluded across all categories. Stratified random sampling uses `random.Random(42)`.

- C1 (Incoming HTTP / GraphQL / FastAPI Endpoints): NestJS `@Controller` + `@(Get|Post|Put|Patch|Delete)`, NestJS GraphQL `@Resolver` + `@(Query|Mutation|Subscription)`, and Python FastAPI `@(app|router).(get|post|put|delete|patch)`.
- C2 (Outbound Inter-Service / External HTTP Calls): `fetch(...)`, `axios.(get|post|put|delete|patch|request)`, `this.httpService.(get|post|...)` (excluding IMAP `imapClient.fetch`).
- C3 & C8 (Message Queues & Async Jobs): `twenty` `enum MessageQueue` (27 queues), `@InjectMessageQueue` producers, `@Processor` + `@Process` consumers; `immich` `enum QueueName` (19 queues) & `enum JobName`, `jobRepository.queue` producers, `@OnJob` consumers.
- C4 & C10 (Database Tables & Schema): `twenty` TypeORM `@Entity` + `@Column`/`@ManyToOne`/`@OneToMany`; `immich` `@Table` + `@Column`/`@ForeignKeyColumn`.
- C5 (Code-to-Table Lineage): `twenty` `@InjectRepository` / `@InjectWorkspaceScopedRepository` read (`find*`, `count`, `createQueryBuilder`) & write (`save`, `insert`, `update`, `delete`, `softDelete`, `upsert`); `immich` Kysely `selectFrom` (read) & `insertInto`/`updateTable`/`deleteFrom` (write).
- C6 (Call Graph): Deterministic sample of 10 service methods across `*.service.ts`, tracing non-test callers invoking `this.<serviceField>.<methodName>(` or `this.<methodName>(`.
- C7 (Inheritance & Implementation): Top 5 base classes/interfaces with ≥3 non-test classes matching `export (abstract )?class <Child> (extends|implements) <Parent>`.