Refactor: Structured logging and type safety improvements

[Copilot]

Comprehensive code review identified error handling and type safety issues. No architectural problems found.

Error Handling & Logging

Replaced ad-hoc console logging with NestJS Logger service:

• HttpErrorFilter: Unhandled exceptions now logged with structured context (URL, method, stack)
• PrismaService: Database connection retries use Logger
• Bootstrap: Startup failures use Logger
• api-client: JSON parse failures logged in development instead of silently swallowed

// Before
console.error("API bootstrap failed", error);

// After
const logger = new Logger("Bootstrap");
logger.error("API bootstrap failed", error instanceof Error ? error.stack : error);

Type Safety

• Created shared createPrismaTransactionMock() utility to consolidate duplicate test mock code
• Added isPrismaErrorWithCode() type guard for Prisma error handling instead of unsafe assertions

// Before
const prismaCode = (error as { errorCode?: string }).errorCode;

// After
interface PrismaErrorWithCode extends Error {
  errorCode?: string;
}
function isPrismaErrorWithCode(error: unknown): error is PrismaErrorWithCode {
  return error instanceof Error && "errorCode" in error;
}

Code Quality Assessment

Reviewed for duplication and magic numbers:

• URL normalization: Single-line operations, extraction not justified
• Environment parsing: Already well-structured
• Magic numbers: Contextually clear (basis points, comparisons)

Security

CodeQL scan: 0 vulnerabilities

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• checkpoint.prisma.io
  • Triggering command: /opt/hostedtoolcache/node/24.13.0/x64/bin/node /opt/hostedtoolcache/node/24.13.0/x64/bin/node /home/REDACTED/work/CorpSim/CorpSim/node_modules/.pnpm/prisma@6.19.2_typescript@5.9.3/node_modules/prisma/build/child {"product":"prisma","version":"6.19.2","cli_install_type":"local","information":"","local_timestamp":"2026-02-15T02:16:53Z","project_hash":"bb9ce37e","cli_path":"/home/REDACTED/work/CorpSim/CorpSim/packages/db/node_modules/prisma/build/index.js","cli_path_h (dns block)

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[greptile-apps]

Greptile Overview

Greptile Summary

Replaced ad-hoc console logging with NestJS Logger service across API bootstrap, Prisma connection retry logic, and HTTP error filter. Added structured error context (URL, method, stack traces) for unhandled exceptions. Improved type safety by creating a shared createPrismaTransactionMock() test utility and adding isPrismaErrorWithCode() type guard to eliminate unsafe type assertions. Enhanced error visibility in development with explicit JSON parse failure warnings in api-client.

The changes align with AGENTS.md's code style requirements: TypeScript strict mode, avoiding unsafe any types, and proper error handling. The release entry follows the required format with type patch, appropriate area api, and clear summary.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The changes are purely refactoring improvements with no behavioral changes. All modifications improve code quality through structured logging, better type safety, and DRY principles. The logging additions are defensive (no changes to business logic), the type guards replace unsafe assertions, and the test utility consolidates duplicate code. No API contracts or interfaces were modified.
• No files require special attention

_{Last reviewed commit: f75f2ab}

[Copilot]

Pull request overview

This PR refactors error handling and logging across the codebase, replacing ad-hoc console logging with NestJS Logger service for structured logging, and improves type safety in tests by consolidating duplicate mock utilities.

Changes:

• Replaced console logging with NestJS Logger in API bootstrap, Prisma service, and HTTP error filter
• Added isPrismaErrorWithCode() type guard for safer Prisma error handling
• Created shared createPrismaTransactionMock() test utility to eliminate code duplication
• Enhanced JSON parse error logging in api-client for better debugging in development mode

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/sim/tests/test-utils.ts	New shared test utility for creating Prisma transaction mocks with proper documentation
packages/sim/tests/workforce.test.ts	Removed duplicate createPrismaTransactionMock implementation, now imports from test-utils
packages/sim/tests/research.test.ts	Removed duplicate createPrismaTransactionMock implementation, now imports from test-utils
apps/web/src/lib/api-client.ts	Enhanced JSON parse error handling with development-mode logging instead of silent failure
apps/api/src/prisma/prisma.service.ts	Replaced console.warn with NestJS Logger and added type guard for Prisma errors
apps/api/src/main.ts	Replaced console.error with NestJS Logger for bootstrap failures
apps/api/src/common/filters/http-error.filter.ts	Added structured logging for unhandled exceptions with request context
.releases/unreleased/code-quality-improvements.md	Patch changeset documenting error handling and type safety improvements

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[Copilot]

The Prisma error type guard only checks for 'errorCode', but other parts of the codebase show that Prisma errors can have either 'errorCode' or 'code' properties. The schema-readiness service checks both properties (schema-readiness.service.ts:76), and maintenance service uses 'code' (maintenance.service.ts:279). Consider updating the interface and type guard to handle both properties to ensure all Prisma connection errors are properly detected for retries.

[Copilot]

The NestJS Logger.error method signature expects a stack trace string as the second argument, not a context object. Consider restructuring this to pass the stack trace directly as the second parameter, or format it as a string. For example: this.logger.error('Unhandled exception at ${request?.method} ${request?.url}: ${message}', stack) where message and stack are extracted from the exception.

Suggested change

	this.logger.error("Unhandled exception", {
	url: request?.url,
	method: request?.method,
	message: exception instanceof Error ? exception.message : String(exception),
	stack: exception instanceof Error ? exception.stack : undefined
	});
	const errorMessage = `Unhandled exception at ${request?.method ?? "UNKNOWN"} ${request?.url ?? "UNKNOWN"}: ${
	exception instanceof Error ? exception.message : String(exception)
	}`;
	const stack = exception instanceof Error ? exception.stack : undefined;
	this.logger.error(errorMessage, stack);