Web

Request → envelope

Envelope field	From
@web.req.method	HTTP verb
@web.req.url.{full,scheme,path,hostname,port,query.<k>.0,query.raw}	URL parts; query values are arrays
@web.req.headers.<name>	Headers (arrays)
@web.req.cookies.<name>	Parsed cookies
@web.req.body	Body, base64-encoded
@web.req.host / @web.req.proto	Host header / protocol
@rid	From X-Request-ID, or a fresh UUID

{
  "_ts": "2026-06-18T16:58:59+02:00",
  "_txc": {
    "_seen": [
      "boot/0->boot/50",
      "boot/50->boot/100"
    ],
    "flag_breakpoint": true,
    "fuel_used": 105,
    "hostname_verified": true,
    "ingress": "host:build-1.local.thanks.computer",
    "rid": "CcAvW7aoT26xqmjgGVZbw",
    "src": "http",
    "stack": "build-1",
    "tenant": "default",
    "ttl": 497,
    "web": {
      "req": {
        "headers": {
          "Accept-Encoding": [
            "gzip"
          ],
          "User-Agent": [
            "Go-http-client/1.1"
          ]
        },
        "host": "build-1.local.thanks.computer",
        "method": "GET",
        "proto": "HTTP/1.1",
        "url": {
          "full": "/",
          "path": "/"
        }
      }
    }
  }
}

Envelope → response

Rules (or ops) shape the response by writing:

• @web.res.status — defaults to 200
• @web.res.headers.<name> — response headers
• @web.res.body — base64; decoded and written raw
• @halt — true — stop execution of further steps.

With no @web.res.body, the response is the merged envelope as JSON, with _-prefixed fields stripped (the privacy convention).

{
  "_txc": {
    "halt": true,
    "web": {
      "res": {
        "body": b64"Thanks, Computer",
        "headers": {
          "content-type": [
            "text/plain; charset=utf-8"
          ]
        },
        "status": 200
      }
    }
  }
}

Which renders as:

HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Server-Timing: total;dur=10
X-Request-Id: CcAw2fqr8j3PmWf5eG9qP
X-Txco-Served-By: imac; sid=CcAvUzHFQWxDcsc44kADw
Date: Thu, 18 Jun 2026 15:05:54 GMT
Content-Length: 17

Thanks, Computer

Streaming: setting @web.res.body in a non-terminal scope locks the status + headers and switches to chunked transfer — each subsequent chunk flushes immediately, with natural backpressure (the processor blocks until the flush completes). HEAD requests and 1xx/204/304 statuses omit body bytes.

Limits and timeouts

• Headers capped at 256 KiB.
• The per-request deadline derives from --op-timeout-max (10m) — deliberately separate from --web-write-timeout (15s), which guards header reads (slowloris), so long-running ops aren’t cut off by the socket timeout.

TLS

Plain HTTP by default — a front proxy terminates TLS. With --web-tls-addr (e.g. :8443) the chassis terminates TLS itself, serving certificates per SNI from its cert manager (ACME DNS-01; requires the dns personality and --acme-email).

Special request signals

Signal	Effect
?_txc.continuation=<id>	Poll a suspended run (continuations)
?_txc.break=N or =stack/N	Breakpoint gate — only with --debug-breakpoints
X-Txco-Mocks: <patterns>	Request-scoped mock patterns — only with --web-mock-header
_txc.admission.* (set by rules)	Denials translate to HTTP status + headers before normal render