create-config-field - SKILL.md Agent Skill

name: create-config-field description: Add a new configuration field to the Datadog Agent (datadog.yaml) allowed-tools: Bash, Read, Write, Edit, Glob, Grep, AskUserQuestion argument-hint: "[config.key.name]" model: sonnet

Add a new configuration field to a Datadog Agent. This involves registering the key with defaults/env bindings in Go, and optionally documenting it in the config template.

There are two separate config objects, each with their own Go init function. Within the core agent config, many subsystems have dedicated setup functions and template sections.

Config objects

Config object	Config file	Go init function
Core Agent	`datadog.yaml`	`InitConfig()` in `pkg/config/setup/config.go`
System Probe	`system-probe.yaml`	`InitSystemProbeConfig()` in `pkg/config/setup/system_probe.go`

Core Agent subsystems

Subsystem	Go setup function	Template conditional	Key prefix examples
Common / General	`agent()` or inline in `InitConfig()`	`.Common`, `.Agent`	`api_key`, `hostname`, `site`
Logs Agent	`logsagent()`	`.LogsAgent`	`logs_config.*`
APM / Trace Agent	`setupAPM()` in `apm.go`	`.TraceAgent`	`apm_config.*`
Process Agent	`setupProcesses()` in `process.go`	`.ProcessAgent`	`process_config.*`
DogStatsD	`dogstatsd()`	`.Dogstatsd`	`dogstatsd_*`
Security Agent	via `InitConfig()`	`.SecurityAgent`	`security_agent.*`
Cluster Agent	via `InitConfig()`	`.ClusterAgent`	`cluster_agent.*`
OTLP	`OTLP()` in `otlp.go`	`.OTLP`	`otlp_config.*`

System Probe subsystems

Subsystem	Go setup function	Template conditional	Key prefix examples
General	`InitSystemProbeConfig()`	`.SystemProbe`	`system_probe_config.*`
CWS	`initCWSSystemProbeConfig()` in `system_probe_cws.go`	`.SecurityModule`	`runtime_security_config.*`
USM	`initUSMSystemProbeConfig()` in `system_probe_usm.go`	`.UniversalServiceMonitoringModule`	`service_monitoring_config.*`
Network	via `InitSystemProbeConfig()`	`.NetworkModule`	`network_config.*`

Instructions

Step 1: Gather information from the user

Use AskUserQuestion to collect the following. If $ARGUMENTS provides the config key name, skip that question.

Target config: Core Agent (datadog.yaml) or System Probe (system-probe.yaml)?
Subsystem: Which subsystem does this field belong to? (see tables above)
Config key (dot-separated, e.g. my_feature.enabled): the YAML path.
Value type: Boolean, String, Integer, Float, Duration, String slice, or Map.
Default value: What should the default be?
Description: Human-readable description of what this field controls.
Scope: Add inline in the subsystem function, or create a dedicated setup file (pkg/config/setup/<feature>.go) for a group of related fields?
User-facing?: Should the rendered example yaml (datadog.yaml, system-probe.yaml, ...) show this setting?

Step 2: Register the config key

Find the right subsystem function from the tables above and add the binding. Use Grep if unsure where related keys live.

config.BindEnvAndSetDefault("my_feature.enabled", false)

For a group of related fields, create pkg/config/setup/<feature>.go with a dedicated setup function, then call it from the appropriate init function. Read an existing setup file (e.g. pkg/config/setup/apm.go) for the pattern.

For serverless-compatible core agent fields, register via the serverlessConfigComponents slice in config.go instead of directly in InitConfig.

Step 3: Regenerate the schema

The example yaml configs (datadog.yaml, system-probe.yaml, etc.) are rendered from the enriched schema under pkg/config/schema/yaml/. The schema is derived from the running agent, so build first, then regenerate:

dda inv agent.build --build-exclude=systemd
dda inv schema.generate --agent-bin=./bin/agent/agent

Commit the resulting changes under pkg/config/schema/yaml/ alongside your Go code.

Step 4: Verify

Lint: dda inv linter.go
Report the results to the user.

Key Methods Reference

BindEnvAndSetDefault(key, default, envVars...) — Preferred. Registers key, sets default, binds DD_* env var.
SetDefault(key, value) — Default without env binding.

BindEnvAndSetDefault("my_feature.timeout", 30) auto-creates DD_MY_FEATURE_TIMEOUT. Custom alias: BindEnvAndSetDefault("my_feature.timeout", 30, "DD_MY_TIMEOUT").

Important Notes

Do NOT use SetKnown for new fields — it's deprecated. Use BindEnvAndSetDefault.
Config priority: default < file < env-var < fleet-policies < agent-runtime < remote-config < cli.
Define exported string constants for keys when creating a dedicated setup file.

Usage

/create-config-field — Interactive: prompts for all details
/create-config-field my_feature.enabled — Pre-fills the key name