Agent-First HTTP

Ask your agent: “Open this link and pull the pricing table out for me.”

What problem does this solve?

Agents are bad at opening pages. Ask one to read a specific URL and it tends to:

• answer from a search-result guess instead of the page you actually named,
• hand back an empty app shell because the page needed JavaScript it never ran, or
• mistake a bot check or login wall for the real content.

afhttp fixes this by loading the actual URL itself — falling back to a real browser of its own to render JavaScript when the page needs one — and returns the page as files the agent can inspect, so it answers from verified content instead of a guess.

That browser is fully isolated: it runs separately from the browser you use every day and never touches your cookies, logins, or history. When a page needs a login, captcha, or 2FA, you can take over that same isolated browser, clear the wall yourself, and let the agent continue — without ever mixing it into your own session.

The basics: hand it a URL, get the page back as data

Give afhttp a URL; it writes the page to disk and prints one line of JSON saying what it got:

$ afhttp fetch https://example.com
{"kind":"result","result":{"code":"fetch","request_url":"https://example.com","status":200,"final_url":"https://example.com/","body_file":"/tmp/afhttp-out/<id>/body.html"},"trace":{}}

That is the whole job: hand it a URL, get the page back as files an agent can read — never a terminal blob to scrape. CLI output follows AFDATA protocol v1: command data is in result; failures use kind: "error" with stable error.code values rather than guesses.

By default afhttp sends a plain HTTP request, returns the raw body_file, and only starts a real browser when the page actually needs one (--render none forces the fast path, --render always forces the browser, --render auto decides). A browser-backed fetch automatically captures more of what a human would look at — an agent-oriented composed page view (content.md, the one to read first), rendered HTML, a screenshot, a DOM observation, the network and console logs — each a flat *_file field on the same JSON, never nested:

{
  "kind": "result",
  "result": {
    "code": "fetch",
    "request_url": "https://example.com",
    "status": 200,
    "final_url": "https://example.com/",
    "body_file": "/tmp/afhttp-out/<id>/body.html",
    "content_file": "/tmp/afhttp-out/<id>/content.md",
    "content_json_file": "/tmp/afhttp-out/<id>/content.json",
    "rendered_html_file": "/tmp/afhttp-out/<id>/rendered.html",
    "text_file": "/tmp/afhttp-out/<id>/text.txt",
    "screenshot_file": "/tmp/afhttp-out/<id>/page.png",
    "network_file": "/tmp/afhttp-out/<id>/network.json",
    "console_file": "/tmp/afhttp-out/<id>/console.json",
    "observation_file": "/tmp/afhttp-out/<id>/observation.json"
  },
  "trace": {}
}

What afhttp covers

The hard part for an agent is not fetching bytes. It is that many useful URLs do not turn into a usable page from a simple shell request — they need JavaScript rendering, cookies, session state, or a real browser fingerprint. Where a human would open a browser and inspect, an agent needs those same facts as data it can branch on. afhttp covers the whole range:

• Plain HTTP fetch when the page works without a browser.
• Browser-backed fetch when it does not — rendered HTML, an agent-readable observation snapshot, screenshot, and network/console logs as artifacts.
• Deep network capture when the visible page is only chrome and the useful data arrives through XHR/fetch/GraphQL calls.
• Raw CDP escape hatch when the agent needs to drive the browser directly (DOM inspection, form submission, custom waits) without going through any “click/type” abstraction layer.
• Human takeover when a person needs to step in on the same browser the agent is using — afhttp fetch <url> --takeover on a takeover-ready host (auto-discovered for the standard local container) hands a person the browser for a login, 2FA, captcha, or security challenge, then lets the agent re-fetch the same tab once the wall is cleared.
• Host health/capabilities and local profile tools so agents can discover backend support and operators can list, inspect, retrieve captured downloads, prune, or delete persistent profiles.

The agent never has to parse a human-readable error message. Every CLI output is an AFDATA protocol-v1 JSON event, and every failure carries a stable error.code. See docs/architecture.md for the full contract.

Two roles: host and driver

afhttp splits into two roles that are independently locatable:

Run the host where the browser needs to be (residential IP, GUI machine, datacenter); run the driver wherever the agent runs. Connectivity is your mesh’s problem, not afhttp’s. The CLI has 11 commands: host, fetch, upload, cdp, panel, health, capabilities, profile, tabs, skill, and container.

Running it: inline for a one-shot, a host for sessions

afhttp fetch <url> with no --endpoint-url runs inline — it spins up a sandboxed browser for that one fetch and tears it down. Zero setup; use it for stateless, one-shot acquisition.

For state that outlives a single fetch — a reused login, a warmed profile, human takeover — run a long-lived host in a container (the isolation boundary). One command builds the image from a recipe embedded in the binary and runs it (Docker, Podman, or Apple container, auto-detected — override with --runtime); it prints structured connection metadata and a ready-to-run driver command without exposing the long-lived host token by default:

afhttp container install

Once it is running, nothing has to be said about it again: every command that needs a host — fetch --takeover, fetch --profile, cdp, tabs, upload, health, capabilities, panel — discovers the standard local afhttp-host and reads its token from the container when --endpoint-url is omitted. No environment variable, no docker exec … cat.

container install is takeover-ready by default (Brave + KasmVNC + an ephemeral initial profile + a 2g /dev/shm). A takeover fetch switches to a persistent per-site profile derived from the URL, and lets a human clear a wall on the same browser the agent drives:

afhttp fetch "$URL" --takeover

If the warmed profile already reaches the target, fetch --takeover just returns the page. Otherwise it keeps a persistent tab open and returns a next_action with kind: "human_takeover", a takeover_url_secret for a human to open, and a recommended_command that re-fetches the same --tab once the wall is cleared. The capability URL is intentionally revealed only in this explicit takeover result; other _secret fields remain redacted. fetch --takeover needs a running host (auto-discovered locally, or supplied with --endpoint-url / AFHTTP_ENDPOINT_URL) and a browser render (--render auto or always); it does not auto-create containers.

Building from a source checkout instead? Use afhttp container install --from-source (or docker compose -f container/docker/compose.yaml up --build when driving the runtime directly). See docs/deployment.md for the full container setup, upgrades, and security posture.

Browser backends: meet each site with the engine it demands

afhttp is not “headless Chromium.” How hard a site fights back decides which engine actually reaches it, so afhttp drives a whole spectrum behind one CDP contract — pick one with --browser (or point --browser-bin at a binary):

• chromium / chrome — the default: full rendering, screenshots, downloads, all artifacts, observation, network body capture, and optional real-display takeover, with multi-attach.
• fingerprint-chromium — the Chromium capability matrix (including optional real-display takeover) plus engine-level fingerprint spoofing (UA, WebGL, canvas, CDP-detection evasion) for bot-walled sites; a stable seed derived from the profile path keeps identity per-profile.
• camoufox (via foxbridge) — a Firefox stealth fork for sites that fingerprint Chromium, driven through the foxbridge CDP→Juggler proxy. Same CDP subset as Lightpanda (no Chromium screenshot), but optional real-display takeover works because the human drives the real X display.
• lightpanda — an ultralight engine covering a rendering subset: HTML / text / network metadata / console / limited observation only — no screenshot, no display takeover (no rendering).
• edge — Microsoft Edge, when a target expects that specific engine; the full Chromium capability matrix.
• brave — Brave, with built-in ad/tracker blocking and the full capability matrix; the default browser a human drives during takeover.
• chrome — Google Chrome, the other takeover backend; reach for it for the web’s most common fingerprint, or when Brave’s Shields break a login flow.
• Any other CDP-compatible browser — launch it yourself; drivers connect via --endpoint-url.

Unsupported per-artifact operations return per-artifact warnings (backend_unsupported), not whole-fetch failures.

Human takeover: a person drives the same browser when a step needs it

When a fetch hits a login, captcha, or 2FA wall, afhttp fetch <url> --takeover keeps a persistent tab open on a takeover-ready host and hands back a complete short-lived takeover_url_secret a human opens to drive the same browser the agent is using, via real-display takeover backed by KasmVNC. Once the human is past the wall, the agent re-fetches the same tab to continue. Without --profile, takeover switches to a persistent profile derived from the URL’s registrable domain. The worked example below shows the full next_action payload.

Handing over a URL leaves the agent guessing when the person is finished. Where a window can open on the agent’s own machine, afhttp ui takeover opens the panel itself and blocks until they close it, so “done” is an event rather than a guess.

Worked examples

One-shot fetch, no host

The shortest path starts with pure HTTP. --render none never starts a browser. With the default --render auto, afhttp tries the same HTTP fast path first and only starts an inline ephemeral host if the response needs browser rendering.

afhttp fetch https://example.com

{
  "code": "fetch",
  "status": 200,
  "final_url": "https://example.com/",
  "body_file": "/tmp/afhttp-out/<id>/body.html",
  "trace": {
    "render_decision": "http_only",
    "render_mode": "auto",
    "render_used": false,
    "current_stage": "complete",
    "duration_ms": 120,
    "timeout_ms": 30000,
    "stages": [
      {"name": "navigate", "status": "ok", "duration_ms": 110},
      {"name": "capture_body", "status": "ok", "duration_ms": 12}
    ]
  }
}

Long-running host + remote fetch

For real workflows: start one afhttp host, drive it from anywhere.

# On the host machine (or in a systemd unit, tmux pane, docker container — your choice).
# A non-loopback listener (anything other than 127.0.0.1 / a unix: socket) serves
# full browser control over /cdp, so a --token-secret is required — the host refuses to
# bind otherwise:
mkdir -p ~/.afhttp && printf '{"work":{"token_secret":"%s"}}\n' \
  "$(head -c 32 /dev/urandom | base64 | tr '+/' '-_' | tr -d '=\n')" > ~/.afhttp/hosts.json
afhttp host --listen tcp:0.0.0.0:9222 --profile work --display headless \
            --token-secret file:$HOME/.afhttp/hosts.json#work.token_secret

# From the agent's machine. --token-secret names where the token is — a config
# file, an environment variable (env:NAME), or a local container
# (container:NAME) — so the secret never goes through the shell:
afhttp fetch --endpoint-url ws://host.mesh.internal:9222 \
             --token-secret file:$HOME/.afhttp/hosts.json#work.token_secret \
             --render auto --wait auto \
             --want rendered_html --want observation --want screenshot \
             --want network --want console \
             --network-bodies xhr \
             https://target.example.com/dashboard

The token secret gates /cdp, display takeover, and /profile; bind tcp:127.0.0.1:<port> or a unix: socket instead when the host and driver share a machine and you want to skip it. The profile persists across host restarts. Cookies and localStorage acquired in one fetch are available to the next.

Raw CDP escape hatch

When fetch is not enough — for example, evaluating arbitrary JavaScript in the target page:

# Against the local afhttp-host container, which is found rather than named:
afhttp cdp Runtime.evaluate \
  --tab abc123 \
  --params '{"expression":"document.querySelectorAll(\"a\").length","returnByValue":true}'
# {"result":{"type":"number","value":42}}

# Against a host elsewhere:
afhttp cdp Runtime.evaluate \
  --endpoint-url ws://host.mesh.internal:9222 \
  --token-secret file:$HOME/.afhttp/hosts.json#work.token_secret \
  --tab abc123 \
  --params '{"expression":"document.querySelectorAll(\"a\").length","returnByValue":true}'

No click / type / navigate wrappers. The agent talks raw CDP; afhttp only forwards.

Check health and capabilities

Before assigning work to a host, an agent or supervisor can ask what is alive and what the backend supports:

afhttp health --endpoint-url ws://host.mesh.internal:9222
# {"kind":"result","result":{"code":"health","status":"ok","backend":{"family":"chromium","connected":true},...},"trace":{}}

afhttp capabilities --endpoint-url ws://host.mesh.internal:9222
# {"kind":"result","result":{"code":"capabilities","artifacts":{"observation":{"supported":true},...},...},"trace":{}}

/health is for readiness. /capabilities is for planning artifact requests and avoiding predictable backend_unsupported warnings.

Human takes over (real-display takeover)

With the default local afhttp container install host running, fetch --takeover discovers its endpoint and token automatically:

afhttp fetch "$URL" --takeover

If the warmed profile already reaches the target, fetch --takeover just returns the content. Otherwise it keeps a persistent tab open and returns a next_action:

{
  "code": "fetch",
  "next_action": {
    "kind": "human_takeover",
    "takeover_url_secret": "http://host.mesh.internal:9222/takeover/panel?handoff_secret=…",
    "takeover_url_expires_at_rfc3339": "2026-06-11T08:15:00Z",
    "takeover_url_ttl_s": 900,
    "takeover_url_scope": "takeover",
    "recommended_command": "afhttp fetch \"$URL\" --tab page-7 --endpoint-url ws://host.mesh.internal:9222 …"
  }
}

A human opens the takeover_url_secret in a local browser and drives the real display (Brave on KasmVNC). Once they are past the wall, the agent runs the recommended_command to re-fetch the same tab and continue. The agent can stay CDP-attached the whole time. afhttp panel --endpoint-url … returns the same short-lived capability in takeover_url_secret. See docs/architecture.md §9 for the risk-control honest assessment.

Manage persistent profiles

Persistent browser profiles are local disk identities. Operators can inspect and clean them up without guessing which temp directory belongs to which host:

afhttp profile list
afhttp profile info work --backend brave
afhttp profile lock-status work --backend brave
afhttp profile downloads work --backend brave
afhttp profile prune --older-than 30d --dry-run
afhttp profile delete old-work --backend brave --confirm old-work

Profile lifecycle commands are local-only; downloads only lists captured files, and destructive commands refuse locked profiles. Profile names are logical and persistent storage is backend-scoped, so work under Brave and work under Chromium are different directories.

From Rust

The library is a thin SDK over the same endpoint protocol. It is not an embedded browser engine; it talks to a running afhttp host over CDP.

use afhttp::{Client, RenderMode, Wait, Artifact};

let client = Client::connect("ws://host.mesh.internal:9222")?;

let result = client.fetch("https://target.example.com")
    .render(RenderMode::Auto)
    .wait(Wait::Auto)
    .timeout(Duration::from_secs(30))
    .want([Artifact::RenderedHtml, Artifact::Observation, Artifact::Screenshot])
    .send()
    .await?;
// result.rendered_html_file -> path on this machine's disk
// result.observation_file -> agent-readable page snapshot

// Dev / test convenience: spawn a host subprocess, use it, kill on drop.
// Requires the `host` feature — pure `features = ["sdk"]` consumers
// connect to an afhttp host started separately.
let local = Client::inline_ephemeral().await?;

Consumers depend on the crate with default-features = false, features = ["sdk"] and link only the client weight — no Chromium, no chromiumoxide, no browser-launch code.

Cross-spore collaboration

afhttp does not operate in isolation. Here is how it fits with the rest of the agentfirstkit suite:

afmail: CAPTCHAs and mail-borne login flows

When a page requires an emailed verification link or OTP, hand off to afmail rather than polling IMAP yourself:

1. afhttp fetch navigates to the login form and submits credentials.
2. The page sends an email. The agent calls afmail triage (or afmail fetch) to find the message, extract the link or code.
3. The agent feeds the link/code back to afhttp via --evaluate-after-wait or a subsequent afhttp fetch.

afhttp handles the browser-side state; afmail handles the mailbox-side state. They share no storage and are always driven by the agent — never by each other.

afpay: profile reuse for payment-gated pages

afhttp holds the browser session (cookies, localStorage) that proves the agent is a logged-in subscriber. afpay handles the wallet and transaction side. The coordination point is the persistent profile:

• Run afhttp host --profile <name> before any payment-gated fetch.
• After afpay completes a purchase, afhttp fetch --endpoint-url <host> uses the same host identity and inherits the session cookies set by the checkout flow.
• Never share --cookie-jar paths across profiles — the isolation invariant requires the jar to live inside the active profile directory.

afdata: field naming alignment

afhttp response fields follow afdata suffix conventions (suffix-typed names: _file, _ms, _url). When an agent passes afhttp artifacts to afdata for extraction, the field shapes should be predictable without a schema lookup. If you add new fields to fetch responses, match the suffix table in the afdata SDK docs.

Adopt it: hand afhttp to your agent

Supported platforms: macOS, Linux, Windows.

The quickest way to find out whether afhttp earns a place in your toolkit is to let your agent read it and tell you. Paste this to your agent:

Read what Agent-First HTTP is at https://agentfirstkit.com/agent-first-http, then tell me in plain terms what it would do for me and whether it fits what I’m working on. If it’s a fit, install it — the prebuilt package for the quick path, or build from source after a quick security review of the repo if you’d rather read what you run — then run afhttp skill install so you follow its behavior rules.

If it’s a fit, install it — a prebuilt package, or from source if you want to read it first:

# prebuilt binary
brew install agentfirstkit/tap/afhttp   # macOS / Linux
scoop bucket add agentfirstkit https://github.com/agentfirstkit/scoop-bucket && scoop install afhttp   # Windows
cargo install agent-first-http          # any platform, from crates.io

# or build from source after reviewing the repo
git clone https://github.com/agentfirstkit/agent-first-http
cargo install --path agent-first-http

Then install the embedded Agent Skill so the agent follows afhttp’s behavior rules — when to escalate --render, when to reach for human takeover, how to read the artifacts. skill install targets Codex, Claude Code, opencode, and Hermes; skill status reports whether each install is present, valid, and current:

afhttp skill install
afhttp skill status

To remove it, run afhttp skill uninstall.

Docs

• Architecture — the canonical contract: roles, CLI surface, profile model, artifacts, health/capabilities endpoints, human takeover, backends, error codes, SDK
• Deployment — running the host in a container: backends, security, human takeover
• Design Principles — codebase-wide conventions
• CLI Reference — flag-by-flag reference for the afhttp binary
• Protocol Reference — output schemas for fetch, cdp, health, capabilities, and profile results
• Testing — test strategy and gates