---
title: "Kiro"
description: "Trace Kiro CLI agent turns, tool calls, and credit usage in Phoenix."
keywords: ["kiro", "kiro tracing", "kiro cli", "phoenix", "agent tracing"]
---

> Trace Kiro CLI agent turns, tool calls, and credit usage in Phoenix for full observability.

Trace your [Kiro](https://kiro.dev) CLI sessions in Phoenix with the [coding-harness-tracing](https://github.com/Arize-ai/coding-harness-tracing) toolkit — every turn shows up as a trace with the model call, each tool it runs, credit cost, and turn duration, grouped into its session. No application code changes required: the toolkit registers hooks on a Kiro agent and streams [OpenInference](https://github.com/Arize-ai/openinference) spans to Phoenix.

## Launch Phoenix

The fastest way to get started with Phoenix is by signing up for a [free Phoenix Cloud account](https://app.arize.com/auth/phoenix/signup). If you prefer, you can also run Phoenix in a [notebook](/docs/phoenix/environments#notebooks), [self-host it](/docs/phoenix/environments#container), or use it directly from your [terminal](/docs/phoenix/environments#terminal).

Go to the settings page in your Phoenix instance to find your **endpoint** and **API key**. A self-hosted Phoenix defaults to `http://localhost:6006`; the API key is only required when auth is enabled.

## Install

The **curl installer** is the simplest — it runs a short wizard that saves your Phoenix credentials for you. Use a **local clone** if you'd rather run the installer from a checkout of the source.

### Curl installer (recommended)

**macOS / Linux:**

```bash
curl -sSL https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.sh | bash -s -- kiro
```

**Windows (PowerShell):**

```powershell
iwr -useb https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.bat -OutFile $env:TEMP\install.bat
& $env:TEMP\install.bat kiro
```

### Local clone

```bash
git clone https://github.com/Arize-ai/coding-harness-tracing.git
cd coding-harness-tracing
./install.sh kiro          # macOS / Linux
install.bat kiro           # Windows
```

The installer prompts you through:

1. **Agent name** — the Kiro agent to install hooks into (default: `arize-traced`)
1. **Set as default** — whether to run `kiro-cli agent set-default <name>` so the agent is used by default
1. **Backend** — select **Phoenix** and enter your endpoint and optional API key
1. **Project name** — project name in your backend (default: `kiro`)
1. **User ID** — optional user identifier added to all spans
1. **Logging** — whether to include prompt text, tool content, and tool details in spans

Once installed, run Kiro as usual. If you set the traced agent as the default during install:

```bash
kiro-cli chat
```

Otherwise, point Kiro at the traced agent explicitly:

```bash
kiro-cli chat --agent arize-traced
```

## Configuration

Credentials live under `harnesses.kiro` in `~/.arize/harness/config.json` (written by the installer). Environment variables override values in `config.json` and can be set in your shell profile so they apply to every Kiro session.

```bash
export PHOENIX_ENDPOINT="http://localhost:6006"
export PHOENIX_API_KEY="<your-api-key>"   # optional, only if auth is enabled
export PHOENIX_PROJECT="kiro"
export ARIZE_TRACE_ENABLED="true"
```

On the Phoenix backend, set the project name with `PHOENIX_PROJECT` (or `PHOENIX_PROJECT_NAME`); `ARIZE_PROJECT_NAME` is Arize-only and ignored here. `ARIZE_TRACE_ENABLED` is a backend-agnostic harness setting and keeps the `ARIZE_` prefix regardless of destination.

### Redaction controls

Each `ARIZE_LOG_*` flag accepts `"true"` or `"false"` and defaults to `"true"`. Set to `"false"` to opt out per category:

```bash
export ARIZE_LOG_PROMPTS="false"
export ARIZE_LOG_TOOL_DETAILS="false"
export ARIZE_LOG_TOOL_CONTENT="false"
```

| Flag | Redacts |
| :--- | :------ |
| `ARIZE_LOG_PROMPTS` | User prompt and assistant response text |
| `ARIZE_LOG_TOOL_DETAILS` | Tool names and arguments |
| `ARIZE_LOG_TOOL_CONTENT` | Tool call output content |

The same flags can be set in `config.json` under `harnesses.kiro.logging` as `log_prompts`, `log_tool_details`, and `log_tool_content` — env vars take precedence.

## Observe

Once tracing is enabled, Kiro activity is streamed to Phoenix. You'll see:

- **Turn traces** — each agent turn (user prompt to assistant response) as a parent LLM span
- **Tool call spans** — one per pre/post tool event pair, parented to the LLM turn
- **Session grouping** — all turns from the same Kiro session grouped by `session.id`
- **Credit cost** — Kiro meters in credits rather than tokens; cost is captured as `kiro.cost.credits`
- **Model and duration** — `llm.model_name`, `kiro.turn_duration_ms`, and `kiro.context_usage_percentage` from the session sidecar

### Span attributes

LLM spans are enriched from the session sidecar at `~/.kiro/sessions/cli/<session_id>.json` with model name, cost in credits, metering usage, and turn duration. Enrichment is fail-soft — if the sidecar is unavailable, the span is emitted with basic attributes only.

| Attribute | Description |
| :-------- | :---------- |
| `session.id` | Kiro session UUID |
| `llm.model_name` | Model ID from the session sidecar |
| `kiro.cost.credits` | Cost in credits from metering data |
| `kiro.metering_usage` | Full metering usage JSON |
| `kiro.turn_duration_ms` | Turn duration in milliseconds |
| `kiro.agent_name` | Name of the Kiro agent |
| `kiro.context_usage_percentage` | Context window usage percentage |

## Known limitations

- **Token counts are 0.** Kiro CLI does not report prompt or completion token counts in current versions and meters in credits instead. Token count attributes are omitted when 0; see `kiro.cost.credits`.
- **FIFO tool matching.** Kiro does not expose a tool-call ID, so pre/post tool events are matched using a FIFO stack. This assumes serial tool execution within a session.
- **Per-workspace agents not supported.** Only global agents under `~/.kiro/agents/` are instrumented.

## Reference

For the full list of environment variables, default file paths, and troubleshooting steps, see the [Kiro tracing README](https://github.com/Arize-ai/coding-harness-tracing/blob/main/tracing/kiro/README.md).

## Uninstall

```bash
curl -sSL https://raw.githubusercontent.com/Arize-ai/coding-harness-tracing/main/install.sh | bash -s -- uninstall kiro
```

Uninstall removes hook entries from every Kiro agent file. If the `arize-traced` agent was created by the installer, that agent file is deleted; pre-existing agents are preserved.

## Resources

<CardGroup>
  <Card
    icon="github"
    href="https://github.com/Arize-ai/coding-harness-tracing"
    title="Arize Coding Harness Tracing"
    horizontal
  />
  <Card
    icon="github"
    href="https://github.com/Arize-ai/openinference"
    title="OpenInference"
    horizontal
  />
  <Card
    icon="book-open"
    href="https://kiro.dev"
    title="Kiro Documentation"
    horizontal
  />
</CardGroup>
