Driving SFX Desk from code

Everything the web app does is available over HTTP. The base URL is https://api.skillsafe.ai/v1/app-api, every request carries Authorization: Bearer <token>, and every response is the same envelope.

The `task` field comes first

This app has five lanes behind one endpoint. Every run body must carry a task field naming the lane - it is what the system prompt routes on. Send the wrong one and you get a valid package of the wrong kind; omit it and the model picks the closest lane and tells you which it chose.

One more shape trap: the run body is the input object. Do not wrap it in an {"input": ...} envelope - that returns 200 while hiding task from the model, which is the most confusing way this API can fail.

task Lane Fields Sections returned

plan Turn a list of picture events into a cue sheet brief, known Summary, The Cue Sheet, The Numbers, Reasoning, Next Step

place Where every file has to start, and where every hit lands sheet, worry Summary, Verdict, Findings, Corrected Sheet, Next Step

nest What from means where, once Sequences nest sheet Summary, The Tree, Every Cue Resolved, What Moving Costs, Next Step

tail What the attack and the decay lose to the window sheet Summary, The Attack, The Decay, What The Window Costs, Next Step

deliver Decide what changes: the times, the runway, or the rate sheet, fixed Summary, A Frame Move Fixes, Only Runway Or Rate Fixes, Nothing Fixes, Next Step

task	Lane	Fields	Sections returned
`plan`	Turn a list of picture events into a cue sheet	`brief, known`	Summary, The Cue Sheet, The Numbers, Reasoning, Next Step
`place`	Where every file has to start, and where every hit lands	`sheet, worry`	Summary, Verdict, Findings, Corrected Sheet, Next Step
`nest`	What `from` means where, once Sequences nest	`sheet`	Summary, The Tree, Every Cue Resolved, What Moving Costs, Next Step
`tail`	What the attack and the decay lose to the window	`sheet`	Summary, The Attack, The Decay, What The Window Costs, Next Step
`deliver`	Decide what changes: the times, the runway, or the rate	`sheet, fixed`	Summary, A Frame Move Fixes, Only Runway Or Rate Fixes, Nothing Fixes, Next Step

Only task and the lane's own required fields are mandatory: sheet on place, nest, tail and deliver; brief on plan. Every field is a string - there are no number fields on this app. sheet is the cue sheet itself: a header of KEY: value lines and up to three blocks, FILES:, SEQUENCES: and CUES:.

preroll= on a FILES line is the number that matters most. It is the distance in milliseconds from the start of the file to its transient, and it is the one number the engine cannot infer - a whoosh carries about 180 ms and a click about 12. Without it a file is placed as if it began at its impact, which is the exact mistake this app exists to catch, so an omitted pre-roll is reported on every answer rather than assumed quietly.

The header takes JOB, FPS and COMPOSITION. Without them the engine assumes 30 fps and 300 frames and says so, and every frame number in the answer is a function of the rate. COMPOSITION is the root durationInFrames, which is the outermost window and therefore what cuts a tail when no Sequence does.

A FILES line takes preroll=, dur=, peak= and kind=hard|soft, all in milliseconds except the peak in dBFS. A SEQUENCES line takes from= and dur= in frames plus in= naming its parent - and because useCurrentFrame() is relative, nested from values ADD, so the tree is what turns a from into an absolute frame. A CUES line takes file= (defaulting to the cue's own name), hit=, in= (defaulting to the root composition) and kind=.

A hit time may be written 1.225s, 1225ms, frame 96, f96, 96f, 00:00:01.225 or 01:23.4. A bare number with a decimal point is seconds and a bare integer is a FRAME, because hit=96 in a Remotion sheet means frame 96 - getting that wrong is wrong by a factor of the frame rate, so the form that was used is stated back on every cue. A hit quoted in frames has no rounding of its own, which halves the worst-case landing error for free.

Anything the reader cannot place is listed as a problem rather than skipped. A sheet whose cue lines were quietly swallowed would read as an empty composition, and every figure in the answer would be a confident statement about nothing.

A FRAME is reported as a bare integer, a time in milliseconds to one place, a landing error signed, a share as a percentage, a level in dBFS to two places, and a from value as from={N}. The engine works in frames and milliseconds: it has decoded no audio and looked at no waveform.

Add $model to any body to choose the model for that run: gpt-5.6-luna, gpt-5.6-terra (the default) or gpt-5.6-sol. Luna caps output at 4,096 tokens and will fail the place, nest and tail lanes rather than shorten them - a findings table, a corrected sheet, or a row per cue and per Sequence, is several thousand characters before the reasoning starts.

The response envelope

Success and failure have the same outer shape, so one check covers both.

{
  "ok": true,
  "data": {
    "...": "the result"
  }
}

{
  "ok": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "seconds should be number, got string",
    "details": {}
  }
}

HTTP error.code What it means

400 VALIDATION_ERROR The body was not a JSON object, or a declared field had the wrong type. A number field sent as a string is the usual cause.

401 UNAUTHORIZED No token, or a token that has expired or been revoked. Mint a new one.

402 INSUFFICIENT_CREDITS The balance is below the run's minimum. Call /estimate first and compare hold_credits against /me.

404 NOT_FOUND Wrong path, or a job id that does not belong to this token.

409 CONFLICT An Idempotency-Key replay whose body differs from the original request.

429 RATE_LIMITED Too many requests. Back off; do not tight-loop.

503 UPSTREAM_UNAVAILABLE The model provider is unavailable. Retry with backoff.

HTTP	error.code	What it means
`400`	`VALIDATION_ERROR`	The body was not a JSON object, or a declared field had the wrong type. A number field sent as a string is the usual cause.
`401`	`UNAUTHORIZED`	No token, or a token that has expired or been revoked. Mint a new one.
`402`	`INSUFFICIENT_CREDITS`	The balance is below the run's minimum. Call /estimate first and compare hold_credits against /me.
`404`	`NOT_FOUND`	Wrong path, or a job id that does not belong to this token.
`409`	`CONFLICT`	An Idempotency-Key replay whose body differs from the original request.
`429`	`RATE_LIMITED`	Too many requests. Back off; do not tight-loop.
`503`	`UPSTREAM_UNAVAILABLE`	The model provider is unavailable. Retry with backoff.

1. Get a token

Open /tokens.html in a browser and copy the token this app already holds - no developer console needed. A guest token is minted automatically and is enough for /me and /estimate; writing a package is metered and needs a personal token, which comes from signing in on that page.

Keep it in an environment variable rather than in source:

export SKILLSAFE_TOKEN="YOUR_TOKEN"

2. Check the session and the balance

GET /me is free. It returns only three fields: subject_type, subject_id and credits. Signed-in means subject_type == "user" - there is no username or email to test.

curl -sS -X GET "https://api.skillsafe.ai/v1/app-api/me" \
  -H "Authorization: Bearer $SKILLSAFE_TOKEN"

import json, urllib.request

TOKEN = "YOUR_TOKEN"   # from /tokens.html
BASE  = "https://api.skillsafe.ai/v1/app-api"

def call(method, path, payload=None, headers=None):
    data = json.dumps(payload).encode() if payload is not None else None
    req = urllib.request.Request(BASE + path, data=data, method=method)
    req.add_header("Authorization", "Bearer " + TOKEN)
    req.add_header("Content-Type", "application/json")
    req.add_header("Accept", "application/json")
    # A plain urllib request with no User-Agent is refused with 403.
    req.add_header("User-Agent", "sfx-desk-client/1.0")
    for k, v in (headers or {}).items():
        req.add_header(k, v)
    with urllib.request.urlopen(req) as r:
        return json.loads(r.read())

out = call("GET", "/me")
print(json.dumps(out["data"], indent=2))

const TOKEN = "YOUR_TOKEN";   // from /tokens.html
const BASE  = "https://api.skillsafe.ai/v1/app-api";

async function call(method, path, payload) {
  const res = await fetch(BASE + path, {
    method,
    headers: {
      "Authorization": `Bearer ${TOKEN}`,
      "Content-Type": "application/json"
    },
    body: payload === undefined ? undefined : JSON.stringify(payload)
  });
  const json = await res.json();
  if (!res.ok || !json.ok) throw new Error(json.error?.message || res.statusText);
  return json.data;
}

const data = await call("GET", "/me");
console.log(data);

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
)

const base = "https://api.skillsafe.ai/v1/app-api"
const token = "YOUR_TOKEN" // from /tokens.html

func main() {
	req, _ := http.NewRequest("GET", base+"/me", nil)
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

import java.net.URI;
import java.net.http.*;

public class Main {
    static final String BASE  = "https://api.skillsafe.ai/v1/app-api";
    static final String TOKEN = "YOUR_TOKEN"; // from /tokens.html

    public static void main(String[] args) throws Exception {
        HttpRequest req = HttpRequest.newBuilder()
            .uri(URI.create(BASE + "/me"))
            .header("Authorization", "Bearer " + TOKEN)
            .header("Content-Type", "application/json")
            .method("GET", HttpRequest.BodyPublishers.noBody())
            .build();
        HttpResponse<String> res = HttpClient.newHttpClient()
            .send(req, HttpResponse.BodyHandlers.ofString());
        System.out.println(res.body());
    }
}

require 'net/http'
require 'json'
require 'uri'

BASE  = "https://api.skillsafe.ai/v1/app-api"
TOKEN = "YOUR_TOKEN" # from /tokens.html

uri = URI("#{BASE}/me")
req = Net::HTTP::Get.new(uri)
req["Authorization"] = "Bearer #{TOKEN}"
req["Content-Type"] = "application/json"
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts JSON.pretty_generate(JSON.parse(res.body)["data"])

<?php
$base  = "https://api.skillsafe.ai/v1/app-api";
$token = "YOUR_TOKEN"; // from /tokens.html

$opts = ["http" => [
    "method"  => "GET",
    "header"  => "Authorization: Bearer $token\r\nContent-Type: application/json\r\n",
]];
$res  = file_get_contents($base . "/me", false, stream_context_create($opts));
$json = json_decode($res, true);
print_r($json["data"]);

using System.Net.Http;
using System.Text;

const string Base  = "https://api.skillsafe.ai/v1/app-api";
const string Token = "YOUR_TOKEN"; // from /tokens.html

var http = new HttpClient();
http.DefaultRequestHeaders.Add("Authorization", $"Bearer {Token}");

var res = await http.SendAsync(new HttpRequestMessage(new HttpMethod("GET"), Base + "/me")
{
    Content = null
});
Console.WriteLine(await res.Content.ReadAsStringAsync());

3. Price the run before making it

POST /estimate costs nothing, creates no job, and returns the worst-case cost. Compare hold_credits against the balance from step 2 before you submit: a 402 after the fact is avoidable. hold_credits is a reservation priced at the full output cap - the actual charge is usually far lower.

It also echoes model, model_alias and markup_bps, which is the authoritative check that a run is bound to the model you think it is. Estimate each lane separately: their prompts and caps differ, so their holds do.

curl -sS -X POST "https://api.skillsafe.ai/v1/app-api/estimate" \
  -H "Authorization: Bearer $SKILLSAFE_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}'

import json, urllib.request

TOKEN = "YOUR_TOKEN"   # from /tokens.html
BASE  = "https://api.skillsafe.ai/v1/app-api"

def call(method, path, payload=None, headers=None):
    data = json.dumps(payload).encode() if payload is not None else None
    req = urllib.request.Request(BASE + path, data=data, method=method)
    req.add_header("Authorization", "Bearer " + TOKEN)
    req.add_header("Content-Type", "application/json")
    req.add_header("Accept", "application/json")
    # A plain urllib request with no User-Agent is refused with 403.
    req.add_header("User-Agent", "sfx-desk-client/1.0")
    for k, v in (headers or {}).items():
        req.add_header(k, v)
    with urllib.request.urlopen(req) as r:
        return json.loads(r.read())

payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
out = call("POST", "/estimate", payload)
print(out["data"]["hold_credits"], out["data"]["model"])

const TOKEN = "YOUR_TOKEN";   // from /tokens.html
const BASE  = "https://api.skillsafe.ai/v1/app-api";

async function call(method, path, payload) {
  const res = await fetch(BASE + path, {
    method,
    headers: {
      "Authorization": `Bearer ${TOKEN}`,
      "Content-Type": "application/json"
    },
    body: payload === undefined ? undefined : JSON.stringify(payload)
  });
  const json = await res.json();
  if (!res.ok || !json.ok) throw new Error(json.error?.message || res.statusText);
  return json.data;
}

const payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
};
const data = await call("POST", "/estimate", payload);
console.log(data.hold_credits, data.model, data.model_alias);

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
)

const base = "https://api.skillsafe.ai/v1/app-api"
const token = "YOUR_TOKEN" // from /tokens.html

func main() {
	payload := []byte(`{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}`)
	req, _ := http.NewRequest("POST", base+"/estimate", bytes.NewReader(payload))
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

import java.net.URI;
import java.net.http.*;

public class Main {
    static final String BASE  = "https://api.skillsafe.ai/v1/app-api";
    static final String TOKEN = "YOUR_TOKEN"; // from /tokens.html

    public static void main(String[] args) throws Exception {
        String payload = """
{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
""";
        HttpRequest req = HttpRequest.newBuilder()
            .uri(URI.create(BASE + "/estimate"))
            .header("Authorization", "Bearer " + TOKEN)
            .header("Content-Type", "application/json")
            .method("POST", HttpRequest.BodyPublishers.ofString(payload))
            .build();
        HttpResponse<String> res = HttpClient.newHttpClient()
            .send(req, HttpResponse.BodyHandlers.ofString());
        System.out.println(res.body());
    }
}

require 'net/http'
require 'json'
require 'uri'

BASE  = "https://api.skillsafe.ai/v1/app-api"
TOKEN = "YOUR_TOKEN" # from /tokens.html

payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}

uri = URI("#{BASE}/estimate")
req = Net::HTTP::Post.new(uri)
req["Authorization"] = "Bearer #{TOKEN}"
req["Content-Type"] = "application/json"
req.body = JSON.dump(payload)
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts JSON.pretty_generate(JSON.parse(res.body)["data"])

<?php
$base  = "https://api.skillsafe.ai/v1/app-api";
$token = "YOUR_TOKEN"; // from /tokens.html

$payload = json_encode([
  "task" => "check",
  "sheet" => "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry" => "it graded fine last time and this one will not come clean",
  "rules" => "<the working rules for this lane, sent by the app>"
]);

$opts = ["http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer $token\r\nContent-Type: application/json\r\n",
    "content" => $payload,
]];
$res  = file_get_contents($base . "/estimate", false, stream_context_create($opts));
$json = json_decode($res, true);
print_r($json["data"]);

using System.Net.Http;
using System.Text;

const string Base  = "https://api.skillsafe.ai/v1/app-api";
const string Token = "YOUR_TOKEN"; // from /tokens.html

var http = new HttpClient();
http.DefaultRequestHeaders.Add("Authorization", $"Bearer {Token}");

var payload = """
{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
""";
var content = new StringContent(payload, Encoding.UTF8, "application/json");
var res = await http.SendAsync(new HttpRequestMessage(new HttpMethod("POST"), Base + "/estimate")
{
    Content = content
});
Console.WriteLine(await res.Content.ReadAsStringAsync());

4. Write a package

POST /run submits the job. Always send an Idempotency-Key: a network blip that replays the same request must not bill twice. A replay with the same key returns the stored result and is not charged again; a replay with the same key but a different body is a 409.

The response carries output.output (the Markdown package), charged_credits and truncated. If truncated is true the balance sat between min_credits and hold_credits and the output was cut short - render what arrived and say so rather than presenting it as complete.

curl -sS -X POST "https://api.skillsafe.ai/v1/app-api/run" \
  -H "Authorization: Bearer $SKILLSAFE_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}'

import json, urllib.request

TOKEN = "YOUR_TOKEN"   # from /tokens.html
BASE  = "https://api.skillsafe.ai/v1/app-api"

def call(method, path, payload=None, headers=None):
    data = json.dumps(payload).encode() if payload is not None else None
    req = urllib.request.Request(BASE + path, data=data, method=method)
    req.add_header("Authorization", "Bearer " + TOKEN)
    req.add_header("Content-Type", "application/json")
    req.add_header("Accept", "application/json")
    # A plain urllib request with no User-Agent is refused with 403.
    req.add_header("User-Agent", "sfx-desk-client/1.0")
    for k, v in (headers or {}).items():
        req.add_header(k, v)
    with urllib.request.urlopen(req) as r:
        return json.loads(r.read())

payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
out = call("POST", "/run", payload)
print(out["data"]["output"]["output"])

const TOKEN = "YOUR_TOKEN";   // from /tokens.html
const BASE  = "https://api.skillsafe.ai/v1/app-api";

async function call(method, path, payload) {
  const res = await fetch(BASE + path, {
    method,
    headers: {
      "Authorization": `Bearer ${TOKEN}`,
      "Content-Type": "application/json"
    },
    body: payload === undefined ? undefined : JSON.stringify(payload)
  });
  const json = await res.json();
  if (!res.ok || !json.ok) throw new Error(json.error?.message || res.statusText);
  return json.data;
}

const payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
};
const data = await call("POST", "/run", payload);
console.log(data.output.output);

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
)

const base = "https://api.skillsafe.ai/v1/app-api"
const token = "YOUR_TOKEN" // from /tokens.html

func main() {
	payload := []byte(`{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}`)
	req, _ := http.NewRequest("POST", base+"/run", bytes.NewReader(payload))
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

import java.net.URI;
import java.net.http.*;

public class Main {
    static final String BASE  = "https://api.skillsafe.ai/v1/app-api";
    static final String TOKEN = "YOUR_TOKEN"; // from /tokens.html

    public static void main(String[] args) throws Exception {
        String payload = """
{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
""";
        HttpRequest req = HttpRequest.newBuilder()
            .uri(URI.create(BASE + "/run"))
            .header("Authorization", "Bearer " + TOKEN)
            .header("Content-Type", "application/json")
            .method("POST", HttpRequest.BodyPublishers.ofString(payload))
            .build();
        HttpResponse<String> res = HttpClient.newHttpClient()
            .send(req, HttpResponse.BodyHandlers.ofString());
        System.out.println(res.body());
    }
}

require 'net/http'
require 'json'
require 'uri'

BASE  = "https://api.skillsafe.ai/v1/app-api"
TOKEN = "YOUR_TOKEN" # from /tokens.html

payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}

uri = URI("#{BASE}/run")
req = Net::HTTP::Post.new(uri)
req["Authorization"] = "Bearer #{TOKEN}"
req["Content-Type"] = "application/json"
req.body = JSON.dump(payload)
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts JSON.pretty_generate(JSON.parse(res.body)["data"])

<?php
$base  = "https://api.skillsafe.ai/v1/app-api";
$token = "YOUR_TOKEN"; // from /tokens.html

$payload = json_encode([
  "task" => "check",
  "sheet" => "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry" => "it graded fine last time and this one will not come clean",
  "rules" => "<the working rules for this lane, sent by the app>"
]);

$opts = ["http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer $token\r\nContent-Type: application/json\r\n",
    "content" => $payload,
]];
$res  = file_get_contents($base . "/run", false, stream_context_create($opts));
$json = json_decode($res, true);
print_r($json["data"]);

using System.Net.Http;
using System.Text;

const string Base  = "https://api.skillsafe.ai/v1/app-api";
const string Token = "YOUR_TOKEN"; // from /tokens.html

var http = new HttpClient();
http.DefaultRequestHeaders.Add("Authorization", $"Bearer {Token}");

var payload = """
{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
""";
var content = new StringContent(payload, Encoding.UTF8, "application/json");
var res = await http.SendAsync(new HttpRequestMessage(new HttpMethod("POST"), Base + "/run")
{
    Content = content
});
Console.WriteLine(await res.Content.ReadAsStringAsync());

5. Stream a run

POST /run-stream is the same call with a text/event-stream response. Worth knowing before you build on it: from a server or from cURL you get event: delta frames carrying the output token by token; from a browser you get event: tick heartbeats and then one event: done with the whole output. Handle both, and treat ticks as liveness rather than progress.

Frame types are job (the job id), delta ({"text": "..."}), tick ({"t": seconds}), done, and error. An idempotent replay returns plain JSON with no stream at all, so check the content type before you start reading frames.

curl -sS -N -X POST "https://api.skillsafe.ai/v1/app-api/run-stream" \
  -H "Authorization: Bearer $SKILLSAFE_TOKEN" \
  -H "Content-Type: application/json" \
  -H "Accept: text/event-stream" \
  -H "Idempotency-Key: cbd-$(date +%s)" \
  -d '{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}'

import json, urllib.request

TOKEN = "YOUR_TOKEN"
BASE  = "https://api.skillsafe.ai/v1/app-api"

payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}

req = urllib.request.Request(BASE + "/run-stream", data=json.dumps(payload).encode(), method="POST")
req.add_header("Authorization", "Bearer " + TOKEN)
req.add_header("Content-Type", "application/json")
req.add_header("Accept", "text/event-stream")
req.add_header("Idempotency-Key", "cbd-demo-1")
req.add_header("User-Agent", "sfx-desk-client/1.0")

event, data = "message", ""
with urllib.request.urlopen(req) as r:
    for raw in r:
        line = raw.decode().rstrip("\n")
        if line.startswith("event:"):
            event = line[6:].strip()
        elif line.startswith("data:"):
            data += line[5:].strip()
        elif line == "":
            if data:
                frame = json.loads(data)
                if event == "delta":
                    print(frame.get("text", ""), end="")
                elif event == "done":
                    print("\n--- charged:", frame.get("charged_credits"))
            event, data = "message", ""

const TOKEN = "YOUR_TOKEN";
const BASE  = "https://api.skillsafe.ai/v1/app-api";

const payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
};

const res = await fetch(BASE + "/run-stream", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${TOKEN}`,
    "Content-Type": "application/json",
    "Idempotency-Key": "cbd-demo-1"
  },
  body: JSON.stringify(payload)
});

// An idempotent replay comes back as plain JSON with no stream at all.
if (!(res.headers.get("content-type") || "").includes("text/event-stream")) {
  const json = await res.json();
  console.log(json.data.output.output);
} else {
  const reader = res.body.getReader();
  const dec = new TextDecoder();
  let buf = "";
  for (;;) {
    const { done, value } = await reader.read();
    if (done) break;
    buf += dec.decode(value, { stream: true });
    let i;
    while ((i = buf.indexOf("\n\n")) >= 0) {
      const frame = buf.slice(0, i);
      buf = buf.slice(i + 2);
      let name = "message", data = "";
      for (const line of frame.split("\n")) {
        if (line.startsWith("event:")) name = line.slice(6).trim();
        else if (line.startsWith("data:")) data += line.slice(5).trim();
      }
      if (!data) continue;
      const p = JSON.parse(data);
      if (name === "delta") process.stdout.write(p.text || "");
      if (name === "tick") console.error("still writing:", p.t + "s");
      if (name === "done") console.log("\ncharged:", p.charged_credits);
    }
  }
}

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
)

const base = "https://api.skillsafe.ai/v1/app-api"
const token = "YOUR_TOKEN" // from /tokens.html

func main() {
	payload := []byte(`{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}`)
	req, _ := http.NewRequest("POST", base+"/run-stream", bytes.NewReader(payload))
	req.Header.Set("Authorization", "Bearer "+token)
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

import java.net.URI;
import java.net.http.*;

public class Main {
    static final String BASE  = "https://api.skillsafe.ai/v1/app-api";
    static final String TOKEN = "YOUR_TOKEN"; // from /tokens.html

    public static void main(String[] args) throws Exception {
        String payload = """
{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
""";
        HttpRequest req = HttpRequest.newBuilder()
            .uri(URI.create(BASE + "/run-stream"))
            .header("Authorization", "Bearer " + TOKEN)
            .header("Content-Type", "application/json")
            .method("POST", HttpRequest.BodyPublishers.ofString(payload))
            .build();
        HttpResponse<String> res = HttpClient.newHttpClient()
            .send(req, HttpResponse.BodyHandlers.ofString());
        System.out.println(res.body());
    }
}

require 'net/http'
require 'json'
require 'uri'

BASE  = "https://api.skillsafe.ai/v1/app-api"
TOKEN = "YOUR_TOKEN" # from /tokens.html

payload = {
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}

uri = URI("#{BASE}/run-stream")
req = Net::HTTP::Post.new(uri)
req["Authorization"] = "Bearer #{TOKEN}"
req["Content-Type"] = "application/json"
req.body = JSON.dump(payload)
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts JSON.pretty_generate(JSON.parse(res.body)["data"])

<?php
$base  = "https://api.skillsafe.ai/v1/app-api";
$token = "YOUR_TOKEN"; // from /tokens.html

$payload = json_encode([
  "task" => "check",
  "sheet" => "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry" => "it graded fine last time and this one will not come clean",
  "rules" => "<the working rules for this lane, sent by the app>"
]);

$opts = ["http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer $token\r\nContent-Type: application/json\r\n",
    "content" => $payload,
]];
$res  = file_get_contents($base . "/run-stream", false, stream_context_create($opts));
$json = json_decode($res, true);
print_r($json["data"]);

using System.Net.Http;
using System.Text;

const string Base  = "https://api.skillsafe.ai/v1/app-api";
const string Token = "YOUR_TOKEN"; // from /tokens.html

var http = new HttpClient();
http.DefaultRequestHeaders.Add("Authorization", $"Bearer {Token}");

var payload = """
{
  "task": "place",
  "sheet": "<FPS, COMPOSITION, FILES with preroll=, SEQUENCES, CUES; the grammar is in /llms.txt>",
  "worry": "it graded fine last time and this one will not come clean",
  "rules": "<the working rules for this lane, sent by the app>"
}
""";
var content = new StringContent(payload, Encoding.UTF8, "application/json");
var res = await http.SendAsync(new HttpRequestMessage(new HttpMethod("POST"), Base + "/run-stream")
{
    Content = content
});
Console.WriteLine(await res.Content.ReadAsStringAsync());

6. Read the result

output.output is Markdown in the envelope this app's system prompt guarantees: every section is a level-two heading spelled exactly as listed in the lane table above, in that order; tables are GitHub pipe tables with the declared columns; prompts are in fenced blocks opened with three backticks and the word text; checklists are - [x] lines.

So parsing is a split on /^## / - but do it fence-aware, because a prompt block can legitimately contain a line starting with ##. Count the sections you got against the ones the lane declares: a short list means the run was truncated, not that the contract changed.

def sections(md):
    out, name, buf, fence = {}, None, [], False
    for line in md.split("\n"):
        if line.lstrip().startswith("```"):
            fence = not fence
        if not fence and line.startswith("## "):
            if name:
                out[name] = "\n".join(buf).strip()
            name, buf = line[3:].strip(), []
            continue
        if name:
            buf.append(line)
    if name:
        out[name] = "\n".join(buf).strip()
    return out

The artifact most callers want is the fenced text block inside ## The Sheet or ## Corrected Sheet - that is a complete sheet in the grammar above, so it can be fed straight back into another lane with nothing carried alongside it. Every other section is prose and tables meant to be read.

Rate limits and good manners

/estimate and /me are free. Call them as much as you like, within reason.
A 429 means back off with a delay, not retry immediately.
Send an Idempotency-Key on every /run. Derive it from a hash of the body plus an attempt counter, so a retry of the same request reuses the key and a deliberate re-run gets a new one.
The engine in the web app is client-side only and has no endpoint. What it computes is published in full in llms.txt - the whole of it is startFrame = hitFrame - round(preRollMs * fps / 1000), plus the consequences. The transient then lands at frameToMs(startFrame) + preRollMs, so the landing error is exactly hitResidual - preRollResidual: TWO roundings, which can cancel or add, so the worst case is a WHOLE frame and not half of one. A Sequence's absolute start is the sum of every from up its chain and its window is the intersection of every ancestor's window with the composition. Clipping the head of a file costs LEVEL AND NOT TIME - an <Audio> is anchored to the frame it is placed at and plays the sample belonging to each rendered frame - so the transient still lands on its frame and the run-up is simply absent; and the transient is heard at all only if the frame it lands on is inside the window, which is the one failure no placement and no frame rate can fix. The tail cut is max(0, startFrame + ceil(durMs * fps / 1000) - windowEnd), and overlapping peaks sum in linear terms. So you can compute every figure this app produces in your own pipeline without it. It is arithmetic on the cue sheet you paste: it has decoded no audio and looked at no waveform; pre-roll is the one number it cannot infer; it reports how much decay a window cuts and not whether that decay clicks; it sums peaks and not loudness; and it models <Sequence> and <Audio> placement and not playbackRate, volume ramps or startFrom/endAt trims applied to the file itself. The composition, every file's pre-roll, the Sequence tree resolved to absolute frames, every cue with its start frame and its from and both roundings and where the transient lands, what the window cuts off either end, the rate sweep, the level sums and every finding are all sent with each run as prescan, and the system prompt requires answering them.