configs-targeting

★ 19

by launchdarkly · part of launchdarkly/agent-skills

Configure config targeting rules to control which variations serve to different users. Enable percentage rollouts, attribute-based rules, segment targeting, and guarded rollouts.

🔌 This skill ships inside the launchdarkly plugin — install the plugin and you also get an MCP server.

This is the playbook your agent receives when the skill activates — you don't need to read it to use the skill, but it's here to audit before installing.

Config Targeting

Configure targeting rules for configs to control which variations serve to different contexts. Works the same for both completion and agent mode.

API Key Detection

Check environment variables - LAUNCHDARKLY_API_KEY, LAUNCHDARKLY_API_TOKEN, LD_API_KEY
Check MCP config - Claude: ~/.claude/config.json -> mcpServers.launchdarkly.env.LAUNCHDARKLY_API_KEY
Prompt user - Only if detection fails

Core Concepts

Evaluation Order

Targeting rules evaluate in this order (same as feature flags):

Individual targets - Specific context keys (highest priority)
Segment rules - Pre-defined segments
Custom rules - Attribute-based conditions (evaluated in order)
Default rule - Fallthrough for all others
Off variation - When targeting is disabled

Semantic Patch API

config targeting uses semantic patch instructions:

PATCH /api/v2/projects/{projectKey}/ai-configs/{configKey}/targeting
Content-Type: application/json; domain-model=launchdarkly.semanticpatch

Key Concepts

variationId: UUIDs, not keys. Always fetch targeting first to get IDs.
Weights: Thousandths (50000 = 50%, 100000 = 100%)
Clause logic: Multiple clauses = AND, multiple values = OR
Null attributes: Rules with null/missing attributes are skipped

Workflow

Step 1: Get Targeting (with Variation IDs)

curl -X GET "https://app.launchdarkly.com/api/v2/projects/{projectKey}/ai-configs/{configKey}/targeting" \
  -H "Authorization: {api_token}" \
  -H "LD-API-Version: beta"

Response includes variations array with _id (UUID) for each variation.

Step 2: Edit the Default Rule

Edit the default rule to serve the variation you created.

Important: The turnTargetingOn instruction does not work for configs. Use updateFallthroughVariationOrRollout instead.

# First, get variation IDs from Step 1 response
# Then set fallthrough to the enabled variation (e.g., "Default" variation)
curl -X PATCH "https://app.launchdarkly.com/api/v2/projects/{projectKey}/ai-configs/{configKey}/targeting" \
  -H "Authorization: {api_token}" \
  -H "Content-Type: application/json; domain-model=launchdarkly.semanticpatch" \
  -H "LD-API-Version: beta" \
  -d '{
    "environmentKey": "production",
    "instructions": [{
      "kind": "updateFallthroughVariationOrRollout",
      "variationId": "your-enabled-variation-uuid"
    }]
  }'

Step 3: Add Targeting Rules

Attribute-based rule:

curl -X PATCH "https://app.launchdarkly.com/api/v2/projects/{projectKey}/ai-configs/{configKey}/targeting" \
  -H "Authorization: {api_token}" \
  -H "Content-Type: application/json; domain-model=launchdarkly.semanticpatch" \
  -H "LD-API-Version: beta" \
  -d '{
    "environmentKey": "production",
    "instructions": [{
      "kind": "addRule",
      "clauses": [{
        "contextKind": "user",
        "attribute": "selectedModel",
        "op": "contains",
        "values": ["sonnet"],
        "negate": false
      }],
      "variation": 0
    }]
  }'

Percentage rollout:

curl -X PATCH "..." \
  -d '{
    "environmentKey": "production",
    "instructions": [{
      "kind": "addRule",
      "clauses": [{
        "contextKind": "user",
        "attribute": "tier",
        "op": "in",
        "values": ["premium"],
        "negate": false
      }],
      "percentageRolloutConfig": {
        "contextKind": "user",
        "bucketBy": "key",
        "variations": [
          {"variation": 0, "weight": 60000},
          {"variation": 1, "weight": 40000}
        ]
      }
    }]
  }'

Set fallthrough (default rule):

curl -X PATCH "..." \
  -d '{
    "environmentKey": "production",
    "instructions": [{
      "kind": "updateFallthroughVariationOrRollout",
      "variationId": "fallback-variation-uuid"
    }]
  }'

Python Implementation

import requests
import os
from typing import Dict, List, Optional

class AIConfigTargeting:
    """Manager for config targeting rules"""

    def __init__(self, api_token: str, project_key: str):
        self.api_token = api_token
        self.project_key = project_key
        self.base_url = "https://app.launchdarkly.com/api/v2"

    def get_targeting(self, config_key: str) -> Optional[Dict]:
        """Get current targeting with variation IDs."""
        url = f"{self.base_url}/projects/{self.project_key}/ai-configs/{config_key}/targeting"

        response = requests.get(url, headers={
            "Authorization": self.api_token,
            "LD-API-Version": "beta"
        })

        if response.status_code == 200:
            return response.json()
        print(f"[ERROR] {response.status_code}: {response.text}")
        return None

    def get_variation_id(self, config_key: str, variation_key: str) -> Optional[str]:
        """Look up variation UUID from key or name."""
        targeting = self.get_targeting(config_key)
        if targeting:
            for var in targeting.get("variations", []):
                if var.get("key") == variation_key or var.get("name") == variation_key:
                    return var.get("_id")
        return None

    def update_targeting(self, config_key: str, environment: str,
                         instructions: List[Dict], comment: str = "") -> Optional[Dict]:
        """Send semantic patch instructions."""
        url = f"{self.base_url}/projects/{self.project_key}/ai-configs/{config_key}/targeting"

        payload = {"environmentKey": environment, "instructions": instructions}
        if comment:
            payload["comment"] = comment

        response = requests.patch(url, headers={
            "Authorization": self.api_token,
            "Content-Type": "application/json; domain-model=launchdarkly.semanticpatch",
            "LD-API-Version": "beta"
        }, json=payload)

        if response.status_code == 200:
            return response.json()
        print(f"[ERROR] {response.status_code}: {response.text}")
        return None

    def enable_config(self, config_key: str, environment: str,
                      variation_key: str = "default") -> bool:
        """
        Enable a config by setting fallthrough to an enabled variation.

        Note: turnTargetingOn doesn't work for configs. Instead, set the
        fallthrough from the disabled variation (index 0) to an enabled one.
        """
        variation_id = self.get_variation_id(config_key, variation_key)
        if not variation_id:
            print(f"[ERROR] Variation '{variation_key}' not found")
            return False
        return self.set_fallthrough(config_key, environment, variation_id)

    def add_rule(self, config_key: str, environment: str,
                 clauses: List[Dict], variation: int,
                 description: str = "") -> bool:
        """Add targeting rule serving a specific variation index."""
        instruction = {
            "kind": "addRule",
            "clauses": clauses,
            "variation": variation
        }
        if description:
            instruction["description"] = description

        result = self.update_targeting(config_key, environment,
            [instruction], f"Add rule: {description}")
        if result:
            print(f"[OK] Rule added")
            return True
        return False

    def add_rollout_rule(self, config_key: str, environment: str,
                         clauses: List[Dict],
                         weights: List[Dict],
                         bucket_by: str = "key") -> bool:
        """
        Add percentage rollout rule.

        weights: [{"variation": 0, "weight": 50000}, {"variation": 1, "weight": 50000}]
        """
        result = self.update_targeting(config_key, environment, [{
            "kind": "addRule",
            "clauses": clauses,
            "percentageRolloutConfig": {
                "contextKind": "user",
                "bucketBy": bucket_by,
                "variations": weights
            }
        }], "Add percentage rollout")
        if result:
            print(f"[OK] Rollout rule added")
            return True
        return False

    def set_fallthrough(self, config_key: str, environment: str,
                        variation_id: str) -> bool:
        """Set default (fallthrough) variation by UUID."""
        result = self.update_targeting(config_key, environment, [{
            "kind": "updateFallthroughVariationOrRollout",
            "variationId": variation_id
        }], "Set fallthrough")
        if result:
            print(f"[OK] Fallthrough set")
            return True
        return False

    def target_individuals(self, config_key: str, environment: str,
                          context_keys: List[str], variation: int,
                          context_kind: str = "user") -> bool:
        """Target specific context keys."""
        result = self.update_targeting(config_key, environment, [{
            "kind": "addTargets",
            "variation": variation,
            "contextKind": context_kind,
            "values": context_keys
        }], f"Target {len(context_keys)} individuals")
        if result:
            print(f"[OK] Individual targets added")
            return True
        return False

    def target_segment(self, config_key: str, environment: str,
                      segment_keys: List[str], variation: int) -> bool:
        """Target a segment."""
        result = self.update_targeting(config_key, environment, [{
            "kind": "addRule",
            "clauses": [{
                "attribute": "segmentMatch",
                "contextKind": "",  # Leave blank for segments
                "op": "segmentMatch",
                "values": segment_keys,
                "negate": False
            }],
            "variation": variation
        }], f"Target segments: {segment_keys}")
        if result:
            print(f"[OK] Segment targeting added")
            return True
        return False

    def clear_rules(self, config_key: str, environment: str) -> bool:
        """Remove all targeting rules."""
        result = self.update_targeting(config_key, environment,
            [{"kind": "replaceRules", "rules": []}], "Clear all rules")
        if result:
            print(f"[OK] All rules cleared")
            return True
        return False

Instruction Reference

Note: turnTargetingOn and turnTargetingOff do not work for configs. Configs have targeting enabled by default. To "enable" a config, set the fallthrough to an enabled variation using updateFallthroughVariationOrRollout.

Rules

Kind	Description
`addRule`	Add rule with clauses and variation/rollout
`removeRule`	Remove by ruleId
`replaceRules`	Replace all rules
`reorderRules`	Change evaluation order
`updateRuleVariationOrRollout`	Update what a rule serves

Fallthrough

Kind	Description
`updateFallthroughVariationOrRollout`	Set default variation or rollout

Individual Targets

Kind	Description
`addTargets`	Target specific context keys
`removeTargets`	Remove specific targets
`replaceTargets`	Replace all targets

Operators Reference

Operator	Description	Example
`in`	Value in list	`["premium", "enterprise"]`
`contains`	String contains	`["sonnet"]`
`startsWith`	String prefix	`["user-"]`
`endsWith`	String suffix	`[".edu"]`
`matches`	Regex match	`["^user-\\d+$"]`
`greaterThan` / `lessThan`	Numeric comparison	`[100]`
`before` / `after`	Date comparison	`["2024-12-31T00:00:00Z"]`
`semVerEqual` / `semVerGreaterThan`	Version comparison	`["2.0.0"]`
`segmentMatch`	Segment membership	`["beta-testers"]`

Clause Structure

{
  "contextKind": "user",
  "attribute": "email",
  "op": "endsWith",
  "values": [".edu"],
  "negate": false
}

Multiple clauses = AND (all must match)
Multiple values = OR (any can match)
negate: true inverts the operator

Rollout Types

Manual Percentage Rollout

{
  "percentageRolloutConfig": {
    "contextKind": "user",
    "bucketBy": "key",
    "variations": [
      {"variation": 0, "weight": 50000},
      {"variation": 1, "weight": 50000}
    ]
  }
}

Progressive Rollout

{
  "progressiveRolloutConfig": {
    "contextKind": "user",
    "controlVariation": 1,
    "endVariation": 0,
    "steps": [
      {"rolloutWeight": 1000, "duration": {"quantity": 4, "unit": "hour"}},
      {"rolloutWeight": 5000, "duration": {"quantity": 4, "unit": "hour"}},
      {"rolloutWeight": 10000, "duration": {"quantity": 4, "unit": "hour"}}
    ]
  }
}

Guarded Rollout

{
  "guardedRolloutConfig": {
    "randomizationUnit": "user",
    "stages": [
      {"rolloutWeight": 1000, "monitoringWindowMilliseconds": 17280000},
      {"rolloutWeight": 5000, "monitoringWindowMilliseconds": 17280000}
    ],
    "metrics": [{
      "metricKey": "error-rate",
      "onRegression": {"rollback": true},
      "regressionThreshold": 0.01
    }]
  }
}

Common Patterns

Model Routing by Attribute

# Route based on selectedModel context attribute
targeting.add_rule(
    config_key="model-selector",
    environment="production",
    clauses=[{
        "contextKind": "user",
        "attribute": "selectedModel",
        "op": "contains",
        "values": ["sonnet"],
        "negate": False
    }],
    variation=0,  # Sonnet variation index
    description="Route sonnet requests"
)

Tier-Based Variation

targeting.add_rule(
    config_key="chat-assistant",
    environment="production",
    clauses=[{
        "contextKind": "user",
        "attribute": "tier",
        "op": "in",
        "values": ["premium", "enterprise"],
        "negate": False
    }],
    variation=0  # Premium model variation
)

Segment Targeting

targeting.target_segment(
    config_key="chat-assistant",
    environment="production",
    segment_keys=["beta-testers"],
    variation=1  # Experimental variation
)

Error Handling

Status	Cause	Solution
400	Invalid semantic patch	Check instruction format, ops must be lowercase
403	Insufficient permissions	Check API token
404	Config not found	Verify projectKey and configKey
422	Invalid variation	Use index (0, 1, 2...) or UUID from targeting response

Next Steps

After configuring targeting:

Provide config URL:

https://app.launchdarkly.com/projects/{projectKey}/ai-configs/{configKey}

Monitor performance with built-in-metrics
Attach judges with online-evals
Set up guarded rollouts for automatic regression detection

configs-create - Create configs with variations
configs-variations - Manage variations
online-evals - Attach judges
segments - Create segments for targeting

References

Copy & paste — that's it

npx skills add https://github.com/launchdarkly/agent-skills --skill configs-targeting

Run this in your project — your agent picks the skill up automatically.

Prerequisites

LaunchDarkly account with AgentControl enabled
API access token with write permissions
Project key and environment key
Existing config with variations (use configs-create skill)