> Markdown version of https://tuna.am/en/blog/new-inspector/. Documentation index: [llms.txt](https://tuna.am/en/llms.txt), full text in one file: [llms-full.txt](https://tuna.am/en/llms-full.txt). Any page is available as Markdown: append `.md` to its URL without the trailing slash.

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# The new inspector, with an API for AI agents

November 10 · 5 min

The inspector is the page at `http://127.0.0.1:4040` that shows everything coming into a tunnel. In tuna-cli 0.40 we rewrote it from scratch and added what was missing: requests that used to get lost, database sessions, and an API for AI agents.

![The new inspector on a wide monitor: request list, a Stripe webhook, request and response in two columns](/docs/img/inspect/http-wide-webhook.webp)

> **In brief**
>
> * **Rejected requests are visible.** A request rejected by `--basic-auth`, `--cidr-allow`, or a traffic policy now shows up in the inspector along with the reason.
> * **Databases.** PostgreSQL, MySQL, and Redis sessions with durations, results, errors, and transactions. The MySQL tunnel is new.
> * **AI agents.** `llms.txt` and an HTTP API: an agent finds a failed request on its own, replays it, and waits for a webhook.
> * **The inspector port** is set with `--inspect-port`. In Docker, the inspector is now off by default.
> * Everything else is in the [documentation](https://tuna.am/en/docs/tunnels/inspect.md).

## HTTP: everything on one screen

The request list and details take the full height of the window. On a wide monitor the request and response sit in two columns, on a laptop you switch between them, and on a phone the list and the details open as separate screens. There's now a dark theme and an English UI.

The search box understands filter tokens: `method:POST`, `status:500`, a header, an IP, a policy rule. Clicking the status or path in the details adds a filter; Alt-click adds an exclusion filter.

A token from the `Authorization` header opens in the JWT decoder in one click, and a timestamp opens in the time converter. We rewrote these tools in Go and covered them with tests: they no longer round large numbers, break Cyrillic in Base64, or shift the time zone.

## Rejected requests

Before, a request rejected by `--basic-auth`, `--key-auth`, `--cidr-*`, a [traffic policy](https://tuna.am/en/docs/traffic-policy.md), or webhook signature verification never reached the inspector. The client got a 401 or 403, the inspector stayed empty, and there was no way to tell whether the request had arrived at all.

Now these requests appear in the list with a Policy label. The details show who answered instead of the application and which rules matched.

![A request to /wp-login.php rejected by the Block scanners policy rule](/docs/img/inspect/http-rejected-policy.webp)

## Edit and replay

Edit opens an editor right in place of the request: method, path, headers as a table, and body, with the original response next to them. A plain replay sends the body byte for byte, so the webhook signature still matches and you can run a Stripe event through your handler again.

![Replay editor with the original response alongside](/docs/img/inspect/http-replay-editor.webp)

## Databases

For [`tuna postgres`](https://tuna.am/en/docs/tunnels/postgres.md), [`tuna redis`](https://tuna.am/en/docs/tunnels/redis.md), and the new [`tuna mysql`](https://tuna.am/en/docs/tunnels/mysql.md), the inspector shows sessions and their queries: duration, result, and errors with a code and a link to its description. Transactions are marked with a bar, and rollbacks with a red one. The Errors and Slow tabs filter the log.

![Postgres session: error 42P01 and a link to the code description](/docs/img/inspect/pg-error.webp)

For Postgres, you see command tags (`UPDATE 1`) and prepared statement parameters. For Redis, you see the database number in the session name, binary values quoted the way `redis-cli` does it, and `MULTI`/`EXEC`. RESP3 and `redis-cli --pipe` work through the tunnel.

![Redis session: a binary PNG value in quotes](/docs/img/inspect/rd-binary.webp)

For MySQL, you see queries, transactions, and `PREPARE`/`EXECUTE`, but not results or errors: the inspector doesn't parse server responses.

The terminal shows the same thing:

## AI agents

Claude Code, Cursor, and other agents read the inspector through its HTTP API. Give the agent a link to `http://127.0.0.1:4040/llms.txt`: it contains instructions with live addresses and ready-made `curl` commands.

```shell
I=http://127.0.0.1:4040
curl -s "$I/v1/events?status=5xx&since=15m"     # what failed in the last 15 minutes
curl -s "$I/v1/events?path=~hook&wait=60s"      # wait for the next webhook
curl -s -X POST "$I/v1/events/<id>/replay"      # replay through the tunnel

```

`wait` covers the common "wait for the webhook" request: the call hangs until a matching event arrives. The Copy for AI button in the request details copies a link to the event: a person who opens it sees the inspector screen, and an agent gets Markdown.

![Warning when copying an event for an AI agent](/docs/img/inspect/http-copy-for-agent.webp)

The inspector masks nothing: tokens, cookies, and request bodies end up in the agent's context and with the model provider. It warns about this when you copy, and `llms.txt` asks the agent not to repeat secrets. Be careful with production data.

## What changes when you upgrade

* **Port.** The first tunnel takes 4040, the next ones 4041, 4042, and so on. Set a fixed port with `--inspect-port` or `TUNA_INSPECT_PORT`. If that port is busy, the tunnel fails to start and names whoever holds it.
* **`inspectAddr` in `tuna.yml` is no longer read.** Set the address with `TUNA_INSPECT_ADDR`; a port in it is deprecated.
* **Docker.** In the `yuccastream/tuna` image, the inspector of `tuna http`, `tuna 1c`, and `tuna kubernetes` is off. If you only set `TUNA_INSPECT_ADDR`, add `TUNA_INSPECT=true`.
* **Network access.** With `TUNA_INSPECT_ADDR=0.0.0.0`, the CLI logs a warning and the inspector shows a banner saying it's open without authorization.

See the [guide](https://tuna.am/en/docs/guides/update.md) for how to update the CLI. Details are on the [inspector](https://tuna.am/en/docs/tunnels/inspect.md) page. Found a bug or missing a feature? Contact [support](https://tuna.am/en/docs/support.md).

## Leave feedback

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![](/blog/img/2024-08-22/feedback.gif)

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Categories: [tuna-cli releases](https://tuna.am/en/blog/tags/releases)

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