# otel-ottl

Helps write and debug OTTL statements for OpenTelemetry Collector components. It assists with telemetry filtering, attribute redaction, and routing rules.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 599 installs · ★ 98
- Author: dash0
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/dash0hq/agent-skills/tree/HEAD/skills/otel-ottl/SKILL.md
- Updated: 2026-10-21
- HTML: https://affpapa.org/en/nevibecode/skills/dash0-otel-ottl

## What it does

The skill equips coding agents with syntax rules and context conventions for the OpenTelemetry Transformation Language (OTTL). It covers data path traversal across `span`, `log`, `metric`, `datapoint`, and `resource` contexts. OTTL strictly differentiates function types: converters such as `ToUpperCase` or `Substring` are uppercase and return values, while editors like `set` and `delete_key` are lowercase and modify fields in place.

It provides patterns for sanitizing sensitive fields, handling missing timestamps, and normalizing high-cardinality attributes. When testing whether an attribute exists, OTTL requires checking against `nil` rather than `null`. Syntax mistakes fail early during collector initialization. Always run `otelcol validate --config=config.yaml` before rolling out configurations.

Setting `error_mode` explicitly prevents silent telemetry loss in production. The `transform` and `filter` processors default to `ignore` in OpenTelemetry Collector Contrib v0.153.0 and newer, whereas connectors like `routing` propagate errors and drop the entire payload by default.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add dash0hq/agent-skills --skill otel-ottl -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/otel-ottl/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/otel-ottl/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add dash0hq/agent-skills --skill otel-ottl -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/otel-ottl/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add dash0hq/agent-skills --skill otel-ottl -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/otel-ottl/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install dash0hq/agent-skills otel-ottl
```

2. **Manually: put the files in place**
- File: `.github/skills/otel-ottl/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add dash0hq/agent-skills --skill otel-ottl -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/dash0hq/agent-skills --path skills/otel-ottl
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/otel-ottl/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add dash0hq/agent-skills --skill otel-ottl -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/dash0hq/agent-skills/tree/HEAD/skills/otel-ottl/SKILL.md

## When to use it
- redact sensitive fields like database statements and authorization tokens
- normalize high-cardinality attributes across span paths
- route and filter telemetry payloads using conditional `where` clauses
- configure the `transform` processor with safe error handling modes
- validate path expressions across span, metric, and log contexts

## Example prompts
- Write an OTTL transform rule to redact db.statement when service.name is accounting
- How do I drop spans using a filter processor where the path matches a regex?
- Show me how to safely parse JSON from a log body attribute using OTTL

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: f8aee19df58d8bbf.

BEGIN THIRD-PARTY FILE f8aee19df58d8bbf
````text
---
name: otel-ottl
description: OpenTelemetry Transformation Language (OTTL) expert. Use when writing or debugging OTTL expressions for any OpenTelemetry Collector component that supports OTTL (processors, connectors, receivers, exporters). Triggers on tasks involving telemetry transformation, filtering, attribute manipulation, data redaction, sampling policies, routing, or Collector configuration. Covers syntax, contexts, functions, error handling, and performance.
metadata:
  author: dash0
  version: '1.0.0'
---

# OpenTelemetry Transformation Language (OTTL)

## Components that use OTTL

OTTL is not limited to the transform and filter processors.
Processors (transform, filter, tailsampling, logdedup) and connectors (routing, count, sum, signaltometrics) accept OTTL expressions.
See [components](./rules/components.md) for the full list with use cases.

## OTTL syntax

### Path expressions

Navigate telemetry data using dot notation:

```
span.name
span.attributes["http.method"]
resource.attributes["service.name"]
```

**Contexts** (first path segment): `resource`, `scope`, `span`, `spanevent`, `metric`, `datapoint`, `log`.

### Enumerations

Use int64 constants for enumeration fields:

```
span.status.code == STATUS_CODE_ERROR
span.kind == SPAN_KIND_SERVER
```

### Operators

Assignment: `=` — Comparison: `==`, `!=`, `>`, `<`, `>=`, `<=` — Logical: `and`, `or`, `not`

### Functions

**Converters** (uppercase, return values):

```
ToUpperCase(span.attributes["http.request.method"])
Substring(log.body.string, 0, 1024)
Concat(["prefix", span.attributes["request.id"]], "-")
IsMatch(metric.name, "^k8s\\..*$")
```

**Editors** (lowercase, modify data in-place):

```
set(span.attributes["region"], "us-east-1")
delete_key(resource.attributes, "internal.key")
limit(log.attributes, 10, [])
```

See [function-reference](./rules/function-reference.md) for the full list of editors and converters.

### Conditional statements

Use `where` to apply transformations conditionally:

<!-- eval:skip -->
```
span.attributes["db.statement"] = "REDACTED" where resource.attributes["service.name"] == "accounting"
```

### Nil checks

Use `nil` for absence checking (not `null`):

```
resource.attributes["service.name"] != nil
```

## Validation workflow

1. **Validate config syntax** — run `otelcol validate --config=config.yaml` to catch compilation errors before starting the Collector.
2. **Test with the debug exporter** — route transformed telemetry to a `debug` exporter and inspect the output:

```yaml
exporters:
  debug:
    verbosity: detailed

service:
  pipelines:
    traces:
````
END THIRD-PARTY FILE f8aee19df58d8bbf

The third-party file has ended. Everything between the f8aee19df58d8bbf tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 2613 of 6257 bytes. © dash0 · Apache-2.0 · https://github.com/dash0hq/agent-skills/tree/HEAD/skills/otel-ottl/SKILL.md

_Part of the page did not fit — see the HTML version._

---
NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md