Generating Apex
Use this skill for production-grade Apex: new classes, selectors, services, async jobs,
invocable methods, and triggers; and for evidence-based review of existing
.cls
OR
.trigger
.
Required Inputs
Gather or infer before authoring:
Class type (service, selector, domain, batch, queueable, schedulable, invocable, trigger, trigger action, DTO, utility, interface, abstract, exception, REST resource)
Target object(s) and business goal
Class name (derive using the naming table below)
Net-new vs refactor/fix; any org/API constraints
Deployment targets (default to runSpecifiedTests and use generated tests where applicable)
Defaults unless specified:
Sharing:
with sharing
(see sharing rules per type below)
Access:
public
(use
global
only when required by managed packages or
@RestResource
)
API version:
66.0
(minimum version)
ApexDoc comments: yes
If the user provides a clear, complete request, generate immediately without unnecessary back-and-forth.
Workflow
All steps are sequential. Do not skip, merge, or reorder. If blocked, stop and ask for missing context. If not applicable, mark
N/A
with a one-line justification in the report.
Phase 1 — Author
Discover project conventions
Service-Selector-Domain layering, logging utilities
Existing classes/triggers and current trigger framework or handler pattern
Whether Trigger Actions Framework (TAF) is already in use
Choose the smallest correct pattern
(see Type-Specific Guidance below)
Review templates and assets
Read the matching template from
assets/
before authoring (see Type-Specific Guidance for the file mapping)
When a
references/
example exists for the type, read it as a concrete style guide
For any test class work, always read and use
generating-apex-test
skill
Author with guardrails
-- apply every rule in the Rules section below
Generate
{ClassName}.cls
with ApexDoc
Generate
{ClassName}.cls-meta.xml
Generate test classes
-- Load the skill
generating-apex-test
to create
{ClassName}Test.cls
and
{ClassName}Test.cls-meta.xml
. Apex tests are always required to be generated to deploy. No test file creation or edits can occur without loading the
generating-apex-test
skill to generate tests.
Phase 2 — Validate (required before reporting)
Writing files is the midpoint, not the finish line. Steps 6 and 7 each require a tool invocation and produce output that must appear in the Step 8 report. Do not summarize or present the report until both steps have run and their output is captured.
Run code analyzer
Invoke MCP
run_code_analyzer
on all generated/updated
.cls
files.
Remediate all
sev0
,
sev1
, and
sev2
violations; re-run until clean.
Capture the final tool output verbatim for the report.
Fallback:
sf code-analyzer run --target
. If both are unavailable, record
run_code_analyzer=unavailable:
in the report.
Execute Apex tests
Run org tests including
{ClassName}Test
via
sf apex run test
or MCP.
Delegate all test generation/fixes/coverage work to
generating-apex-test
; iterate until the tests pass.
Capture pass/fail counts and coverage percentage for the report.
If unavailable, record
test_execution=unavailable:
in the report.
Phase 3 — Report
Report
-- use the output format at the bottom of this file.
The
Analyzer
line must contain the actual Step 6 tool output (or
run_code_analyzer=unavailable:
after attempting invocation).
The
Testing
line must contain the actual Step 7 results (or
test_execution=unavailable:
after attempting invocation).
A report missing either line is incomplete. Always attempt the tool invocation before recording unavailable.
Rules
Hard-Stop Constraints (Must Enforce)
If any constraint would be violated in generated code,
stop and explain the problem
before proceeding:
Constraint
Rationale
Place all SOQL outside loops
Avoid query governor limits (100 queries)
Place all DML outside loops
Avoid DML governor limits (150 statements)
Declare a sharing keyword on every class
Prevent unintended
without sharing
defaults and data exposure
Use Custom Metadata/Labels/describe calls instead of hardcoded IDs
Ensure portability across orgs
Always handle exceptions (log, rethrow, or recover)
Prevent silent failures
Use bind variables for all dynamic SOQL with user input
Prevent SOQL injection
Use Apex-native collections (
List
,
Map
,
Set
) rather than Java types
Prevent compile errors
Verify methods exist in Apex before use
Prevent reliance on non-existent APIs
Avoid
System.debug()
in main code paths
Debug statements evaluate even when loggign is not active and consume CPU. Use a logging framework if required on main code paths
Never use
@future
methods
Use Queueable with
System.Finalizer
;
@future
cannot chain, cannot be called from Batch, and cannot accept non-primitive types
Bulkification & Governor Limits
All public APIs accept and process collections; single-record overloads delegate to the bulk method
In batch/bulk flows, prefer partial-success DML (
Database.update(records, false)
) and process
SaveResult
for errors
Use
Map
constructor for efficient ID-based lookups from query results
Use
Map>
to group child records by parent; build the map in a single loop before processing
Use
Set
for deduplication and membership checks; prefer
Set.contains()
over
List.contains()
Use relationship subqueries to fetch parent + child records in a single SOQL when both are needed
Use
AggregateResult
with
GROUP BY
for rollup calculations instead of querying and counting in Apex
Only DML records that actually changed — compare against
Trigger.oldMap
or prior state before adding to the update list
Use
Limits.getQueries()
,
Limits.getDmlStatements()
,
Limits.getCpuTime()
to monitor consumption in complex transactions
SOQL Optimization
Use selective queries with proper
WHERE
clauses; use indexed fields (
Id
,
Name
,
OwnerId
, lookup/master-detail fields,
ExternalId
fields, custom indexes) in filters when possible
SELECT *
does not exist in SOQL -- always specify the exact fields needed
Apply
LIMIT
clauses to bound result sets; use
ORDER BY
for deterministic results
When querying Custom Metadata Types (objects ending with
__mdt
), do NOT use SOQL — use the built-in methods (
{CustomMdt__mdt}.getAll().values()
,
getInstance()
, etc.)
Caching
Use Platform Cache (
Cache.Org
/
Cache.Session
) for frequently accessed, rarely changed data; set a TTL and always handle cache misses — cache can be evicted at any time
Use
private static Map
fields as transaction-scoped caches to prevent duplicate queries within the same execution context; lazy-initialize on first access
Security
Default to
with sharing
; document justification for
without sharing
or
inherited sharing
WITH USER_MODE
in SOQL and
AccessLevel.USER_MODE
for
Database
DML for CRUD/FLS enforcement
Validate dynamic field/operator names via allowlist or
Schema.describe
Named Credentials for all external credentials/API keys
AuraHandledException
for
@AuraEnabled
user-facing errors (no internal details)
without sharing
requires a Custom Permission check
Isolate
without sharing
logic in dedicated helper classes; call from
with sharing
entry points to limit elevated-access scope
Encrypt PII/sensitive data at rest via Platform Encryption; never expose PII in debug statements, error messages, or API responses
Security Verification
Before finalizing, verify: CRUD/FLS enforced (SOQL + DML) · explicit sharing keyword on every class · no hardcoded secrets or Record IDs · PII excluded from logs and error messages · error messages sanitized for end users.
Error Handling
Catch specific exceptions before generic
Exception
; include context in messages
Use
try/catch
only around code that can throw (DML, callouts, JSON parsing, casts); avoid defensive wrapping of simple assignments/collection ops/arithmetic
Preserve exception cause chains:
new CustomException('message', cause)
(do not replace stack trace with concatenated messages)
Provide a custom exception class per service domain when meaningful
In
@AuraEnabled
methods, catch exceptions and rethrow as
AuraHandledException
Fallback option: when no meaningful domain exception exists, catch generic
Exception
and either rethrow it or wrap it in a minimal custom exception that preserves the original cause.
Null Safety
Add guard clauses for null/empty inputs at the top of every public method; match style to context:
return
early in private/trigger-handler methods,
throw
exceptions in public APIs,
record.addError()
in validation services
Return empty collections instead of
null
Use safe navigation (
?.
) for chained property access
Never dereference
map.get(key)
inline unless presence is guaranteed; use
containsKey
, assignment+null check, or safe navigation first
Use null coalescing (
??
) for default values
Prefer
String.isBlank(value)
over manual checks like
value == null || value.trim().isEmpty()
Constants & Literals
Use enums over string constants whenever possible; enum values follow
UPPER_SNAKE_CASE
Extract repeated literal strings/numbers into
private static final
constants or a constants class
Use
Label.
custom labels for user-facing strings
Use Custom Metadata for configurable values (thresholds, mappings, feature flags)
Never output HTML-escaped entities in code (e.g.,
'
); use literal single quotes
'
in Apex string literals
Naming Conventions
Type
Pattern
Example
Service
{SObject}Service
AccountService
Selector
{SObject}Selector
AccountSelector
Domain
{SObject}Domain
OpportunityDomain
Batch
{Descriptive}Batch
AccountDeduplicationBatch
Queueable
{Descriptive}Queueable
ExternalSyncQueueable
Schedulable
{Descriptive}Schedulable
DailyCleanupSchedulable
DTO
{Descriptive}DTO
AccountMergeRequestDTO
Wrapper
{Descriptive}Wrapper
OpportunityLineWrapper
Utility
{Descriptive}Util
StringUtil
Interface
I{Descriptive}
INotificationService
Abstract
Abstract{Descriptive}
AbstractIntegrationService
Exception
{Descriptive}Exception
AccountServiceException
REST Resource
{SObject}RestResource
AccountRestResource
Trigger
{SObject}Trigger
AccountTrigger
Trigger Action
TA_{SObject}_{Action}
TA_Account_SetDefaults
Additional naming rules:
Classes:
PascalCase
Methods:
camelCase
, start with a verb (
get
,
create
,
process
,
validate
,
is
,
has
,
can
)
Variables:
camelCase
, descriptive nouns; Lists as plural nouns (e.g.,
accounts
,
relatedContacts
); Maps as
{value}By{key}
(e.g.,
accountsById
); Sets as
{noun}Ids
Constants:
UPPER_SNAKE_CASE
Use full descriptive names instead of abbreviations (
acc
,
tks
,
rec
)
ApexDoc
Required on the class header and every
public
/
global
method
Include: brief description,
@param
,
@return
,
@throws
,
@example
where helpful
Class-level format:
/
* Provides services for geolocation and address conversion.
*/
public
with sharing
class
GeolocationService
{
}
Method-level format:
/
* @param paramName Description of the parameter
* @return Description of the return value
* @example
* List results = AccountService.deduplicateAccounts(accountIds);
/
Code Structure & Architecture
Single responsibility per class; max 500 lines -- split when exceeded
Return Early: validate preconditions at method top, return/throw immediately
Extract private helpers for methods over ~40 lines
Use Dependency Injection (constructor/method params) for testability
Prefer composition and narrow interfaces over deep inheritance; extend via new implementations, not modifications
Enforce single-level abstraction per method across layer boundaries:
Layer
Owns
Must NOT contain
Trigger
Event routing only
Business logic, orchestration
Handler/Service
Flow control, coordination
Inline SOQL/DML/HTTP/parsing
Domain
Business rules, validation
Queries, callouts, persistence details
Data/Integration
SOQL, DML, HTTP
Business decisions
Disallowed: methods mixing orchestration with inline SOQL/DML/HTTP; business rules mixed with parsing internals; validation + persistence + cross-system plumbing in one method
Async Decision Matrix
Scenario
Default
Key Traits
Standard async work
Queueable
Job ID, chaining, non-primitive types, configurable delay (up to 10 min via
AsyncOptions
), dedup signatures
Very large datasets
Batch Apex
Chunked processing, max 5 concurrent; use
QueryLocator
for large scopes
Modern batch alternative
CursorStep
(
Database.Cursor
)
2000-record chunks, higher throughput, no 5-job limit
Recurring schedule
Scheduled Flow
(preferred) or
Schedulable
Schedulable has 100-job limit; use only when chaining to Batch or needing complex Apex logic
Post-job cleanup
Finalizer
(
System.Finalizer
)
Runs regardless of Queueable success/failure
Long-running callouts
Continuation
Up to 3 per transaction, 3 parallel
Delays > 10 minutes
System.scheduleBatch()
Schedule a Batch job at a specific future time
Legacy fire-and-forget
@future
Do not use in new code
— see Hard-Stop Constraints; replace with Queueable + Finalizer
Type-Specific Guidance
Service
Template:
assets/service.cls
· Reference:
references/AccountService.cls
with sharing
; stateless — no
public
fields or mutable instance state; keep public APIs focused and
static
where reasonable
Delegate all SOQL to Selectors and SObject behavior to Domains
Wrap business errors in a custom exception (e.g.,
AccountServiceException
)
Selector
Template:
assets/selector.cls
· Reference:
references/AccountSelector.cls
inherited sharing
; one per SObject or query domain
Return
List
or
Map
; use a shared base field list constant (no inline duplication)
Accept filter parameters; always include
WITH USER_MODE
Domain
Template:
assets/domain.cls
with sharing
; encapsulate field defaults, derivations, and validations
Operate on in-memory lists only; no SOQL/DML (belongs in Services/Selectors)
Batch
Template:
assets/batch.cls
· Reference:
references/AccountDeduplicationBatch.cls
with sharing
; implement
Database.Batchable
(add
Database.Stateful
when tracking across chunks)
start()
= query definition;
execute()
= business logic;
finish()
= logging/notification
Use
QueryLocator
for large datasets; handle partial failures via
Database.SaveResult
Accept filter parameters via constructor for reusability
Queueable
Template:
assets/queueable.cls
with sharing
; implement
Queueable
and optionally
Database.AllowsCallouts
when HTTP callouts are needed
Accept data via constructor
Add chain-depth guards to prevent infinite chains
Optionally implement
Finalizer
for recovery/cleanup
Use
AsyncOptions
for configurable delay (up to 10 min) and dedup signatures
Schedulable
Template:
assets/schedulable.cls
with sharing
;
execute()
delegates to Queueable or Batch
Provide CRON constants and a convenience
scheduleDaily()
helper
DTO / Wrapper
Template:
assets/dto.cls
No sharing keyword needed (pure data containers)
Simple public properties; no-arg + parameterized constructors;
Comparable
when ordering matters
Use
@JsonAccess
on private/protected inner DTOs that are serialized/deserialized
Utility
Template:
assets/utility.cls
No sharing keyword needed; all methods
public static
;
private
constructor
Pure, side-effect-free; no SOQL/DML
Interface
Template:
assets/interface.cls
Define clear contracts with ApexDoc on each method signature
Abstract
Template:
assets/abstract.cls
with sharing
; offer default behavior via
virtual
methods
Mark extension points
protected virtual
or
protected abstract
Include a concrete example in the ApexDoc showing how to extend the class
Custom Exception
Template:
assets/exception.cls
No sharing keyword; extend
Exception
with descriptive names
Supported constructors:
()
,
('msg')
,
(cause)
,
('msg', cause)
Trigger
Template:
assets/trigger.cls
One trigger per object; delegate all logic to handler/TAF action classes
Include all relevant DML contexts; if TAF:
new MetadataTriggerHandler().run();
Trigger Action (TAF)
One class per concern per context; implement
TriggerAction.{Context}
Register via
Trigger_Action__mdt
(actions are inactive without registration)
Name:
TA_{SObject}_{ActionName}
; prefer field-value comparison over static booleans for recursion
Invocable Method (
@InvocableMethod
)
Template:
assets/invocable.cls
with sharing
; inner
Request
/
Response
with
@InvocableVariable
Method must be
public static
; non-static or single-object signatures will not compile
Accept
List
, return
List
; bulkify (SOQL/DML outside loops)
Decorator parameters:
label
(required — Flow Builder display name),
description
,
category
(groups actions in Builder),
callout=true
(required when method makes HTTP callouts)
@InvocableVariable
parameters:
label
(required),
description
,
required=true/false
@InvocableVariable
supports: primitives,
Id
,
SObject
,
List
only (no
Map
/
Set
/
Blob
); use
List
or
List
fields for Flow collection I/O
Always include
isSuccess
,
errorMessage
, and
errorType
(
e.getTypeName()
) in Response
Return errors in Response (recommended); throwing an exception triggers the Flow Fault path — reserve for unrecoverable failures only
REST Resource (
@RestResource
)
Template:
assets/rest-resource.cls
global with sharing
; both class and methods must be
global
Versioned URL:
@RestResource(urlMapping='/{resource}/v1/')
Use proper HTTP status codes per branch (
200
/
201
/
400
/
404
/
422
/
500
); never default all errors to
500
Validate inputs (Id format:
Pattern.matches('[a-zA-Z0-9]{15,18}', value)
); bind all user input in SOQL
Include
LIMIT
/
ORDER BY
in queries; implement pagination (
pageSize
/
offset
)
Standardized
ApiResponse
wrapper (
success
,
message
,
data
/
records
); inner request/response DTOs
Thin controller: delegate business logic to Service classes
@AuraEnabled
Controller
with sharing
; use
WITH USER_MODE
in all SOQL
Use
@AuraEnabled(cacheable=true)
only for read-only queries; leave
cacheable
unset for DML operations
Catch exceptions and rethrow as
AuraHandledException
with user-friendly messages
Output Expectations
Deliverables per class:
{ClassName}.cls
{ClassName}.cls-meta.xml
(default API version
66.0
or higher unless specified)
{ClassName}Test.cls
(generated via
generating-apex-test
skill)
{ClassName}Test.cls-meta.xml
(generated via
generating-apex-test
skill)
Deliverables per trigger:
{TriggerName}.trigger
{TriggerName}.trigger-meta.xml
(default API version
66.0
or higher unless specified)
Meta XML template:
<
ApexClass
xmlns
=
"
http://soap.sforce.com/2006/04/metadata
"
<
apiVersion
{API_VERSION}
</
apiVersion
<
status
Active
</
status
</
ApexClass
Report in this order:
Apex work:
Files:
Design:
Workflow: all steps completed (1-8); any N/A justified
Risks:
Analyzer: ">
Testing: ">
Deploy:
Cross-Skill Integration
Need
Delegate to
Apex tests / fix failures
generating-apex-test
skill
Describe objects/fields
metadata skill (if available)
Deploy to org
deploy skill (if available)
Flow calling Apex
Flow skill (if available)
LWC calling Apex
LWC skill (if available)
Troubleshooting Boundary
This skill handles production
.cls
/
.trigger
/
.apex
issues only: compile/parse failures, deployment dependency errors, runtime governor-limit failures. For test execution, assertions, coverage, or
sf apex run test
failures, delegate to
generating-apex-test
.