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

Core Agent subsystems

System Probe subsystems

Instructions

Step 1: Gather information from the user

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

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

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: (Optional) Document in the config template

If user-facing, add documentation to pkg/config/config_template.yaml inside the appropriate conditional block (see Template conditional column in tables above). Read existing entries nearby for the exact format (@param, @env annotations).

Step 4: Verify

1. Build: dda inv agent.build --build-exclude=systemd (or dda inv system-probe.build)
2. Lint: dda inv linter.go
3. If the template was modified: dda inv generate-config
4. 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.
• BindEnv(key, envVars...) — Env binding without default.

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