Developer Documentation

Zero to first gate call
in under 10 minutes.

One endpoint. One header. POST before each step — the gate returns ALLOW or DENY. Your agent only proceeds on ALLOW.

Gate live — https://agenticrail.nz/evaluate
How it works

Three steps. No magic.

Every gate call follows the same path. Your agent sends a request. The gate enforces sequence. You get a receipt or a halt.

01
Send request

POST to /evaluate with your agent's current step, a unique nonce, and a timestamp. Auth via the x-slp8-key header.

02
Gate enforces sequence

The gate validates step order, checks the nonce for replay, verifies function and action_type against the policy for this step, and confirms the sequence is not sealed. All checks must pass.

03
Receive receipt or halt

On pass: a cryptographic receipt with decision ALLOW. On failure: a DENY with a reason code. Your agent only proceeds on ALLOW.

Authentication

One header. Every request.

All requests require the x-slp8-key header. The demo key is public and rate-limited — use it to test without signing up.

Demo key — public, free to use
DEMO-AGENTICRAIL-PUBLIC-2026

Add to every request: x-slp8-key: DEMO-AGENTICRAIL-PUBLIC-2026

For production use, contact hello@agenticrail.nz for a private key with no rate limits.

Request format

Fields, one by one.

All requests are Content-Type: application/json via POST. Fields are validated in order — a missing required field halts at gate step 1.

Field Type Description
schema_version string Always "1.0"
sequence_id string Unique per sequence — e.g. a UUID or session ID. Groups steps together.
step string Canonical step name — must match function. Sequence: intake → disruption → instability → state_read → internal_driver → execution → boundary → settle. Must run in order. No skipping.
function string Canonical function name — must equal step. e.g. "intake", "execution". Used for policy lookup.
action_type string Canonical action type for this step. Must be in the allowed set for the function. e.g. "CHECK_STATE", "RECORD_RESULT", "WAIT_FOR_SIGNAL".
model_id string Your agent identifier — e.g. "my-agent-v2".
nonce string Unique hex string per request. Used for replay protection — never reuse.
action string Descriptive action label for this step. e.g. "run intake", "run execution".
ts_ms number Unix timestamp in milliseconds. Required — use Date.now() or equivalent.
inputs object Optional. Any context you want to log alongside the step.
Quickstart

Copy. Paste. Run.

This example works against the live gate right now. Replace ts_ms with the current Unix timestamp in milliseconds before running.

curl — bash / mac / linux 
# Get current timestamp: date +%s%3N
curl -X POST https://agenticrail.nz/evaluate \\
  -H 'Content-Type: application/json' \\
  -H 'x-slp8-key: DEMO-AGENTICRAIL-PUBLIC-2026' \\
  -d '{
    "schema_version": "1.0",
    "model_id":       "my-agent",
    "sequence_id":    "my-seq-001",
    "step":           "intake",
    "function":       "intake",
    "action_type":    "CHECK_STATE",
    "action":         "run intake",
    "nonce":          "a1b2c3d4e5f6",
    "ts_ms":          1741654800000,
    "inputs":         {}
  }'
powershell — windows 
# Paste all four lines at once into PowerShell
$ts = [DateTimeOffset]::UtcNow.ToUnixTimeMilliseconds()
$body = '{"schema_version":"1.0","model_id":"my-agent","sequence_id":"my-seq-001","step":"intake","function":"intake","action_type":"CHECK_STATE","action":"run intake","nonce":"a1b2c3d4e5f6","ts_ms":' + $ts + ',"inputs":{}}'
$headers = @{ "Content-Type" = "application/json"; "x-slp8-key" = "DEMO-AGENTICRAIL-PUBLIC-2026" }
(Invoke-WebRequest -UseBasicParsing -Uri https://agenticrail.nz/evaluate -Method POST -Headers $headers -Body $body).Content

ts_ms is a required field — pass the current Unix timestamp in milliseconds. On Mac/Linux: date +%s%3N. On Windows: [DateTimeOffset]::UtcNow.ToUnixTimeMilliseconds() as shown above.

javascript 
// One gate call — adapt into your agent loop
const res = await fetch('https://agenticrail.nz/evaluate', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'x-slp8-key':    'DEMO-AGENTICRAIL-PUBLIC-2026',
  },
  body: JSON.stringify({
    schema_version: '1.0',
    model_id:       'my-agent',
    sequence_id:    'my-seq-001',
    step:           'intake',
    function:       'intake',
    action_type:    'CHECK_STATE',
    action:         'run intake',
    nonce:          crypto.randomUUID().replace(/-/g, '').slice(0, 16),
    ts_ms:          Date.now(),
    inputs:         {},
  }),
});

const gate = await res.json();

if (gate.pack?.decision === 'ALLOW') {
  // Proceed with your step
} else {
  // Halt — do not proceed
  console.error('DENY:', gate.pack?.reasons);
}
Response reference

ALLOW or DENY. Nothing in between.

Every response has a top-level status of "OK" or "HALT", and a pack object with the decision details.

✓ ALLOW — step accepted
{
  "status":  "OK",
  "pack": {
    "decision":  "ALLOW",
    "reasons":   [],
    "executed":  true,
    "meta": {
      "step":        "intake",
      "function":    "intake",
      "action_type": "CHECK_STATE"
    }
  },
  "pack_id":  "a7f3c2d4...e91b"
}
✗ DENY — sequence violation
{
  "status":  "OK",
  "pack": {
    "decision": "DENY",
    "reasons":  ["SEQUENCE_VIOLATION"],
    "executed": false
  },
  "pack_id":  "c9f2d1a3...f82e"
}
Reason code
Meaning
SEQUENCE_VIOLATION
Step arrived out of order — e.g. instability before disruption.
REPLAY_NONCE
Nonce has already been used. Generate a fresh nonce per request.
SEALED_SEQUENCE
This sequence has already been completed. Start a new sequence_id.
ACTION_NOT_ALLOWED
action_type is not in the allowed set for this function/step.
NO_POLICY_MATCH
function value is not a recognised step name.
FUNCTION_STEP_MISMATCH
function and step fields do not match.
missing_*
Required field absent — e.g. missing_function, missing_action_type, missing_nonce.
METHOD_NOT_ALLOWED
Request was not a POST. Only POST is accepted.
UNAUTHORIZED
Missing or invalid x-slp8-key header.
SCHEMA_VIOLATION
Body parse error, wrong content-type, or body too large.
Sequence rules

The rules the gate enforces.

These aren't soft guidelines. A violation on any one of them returns DENY immediately.

Steps must run in order. intake → disruption → instability → state_read → internal_driver → execution → boundary → settle. No skipping. An out-of-order step returns SEQUENCE_VIOLATION.
Nonces are single-use. Each request must supply a unique nonce. Reusing any nonce — even from a prior sequence — returns REPLAY_NONCE.
function and action_type must be valid. function must match step. action_type must be in the allowed set for that function. Invalid combinations return ACTION_NOT_ALLOWED or FUNCTION_STEP_MISMATCH.
Sequences seal after completion. Once settle is accepted, the sequence locks. Any further request on that sequence_id returns SEALED_SEQUENCE. Start a new sequence with a fresh ID.
Only POST is accepted. GET, PUT, PATCH and all other methods return METHOD_NOT_ALLOWED immediately.
SDKs & next steps

Ready to go further?

The demo key is open for testing. When you're ready for production — dedicated rate limits, private key, support — get in touch.

Get a production key

No rate limits. Private key. Direct support. Contact us and we'll have you set up within 24 hours.

hello@agenticrail.nz →

SDK integrations and language-specific wrappers are in progress. Watch the GitHub repo or subscribe to the blog for updates.