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Decosa API

Every tool on this site and the open models under it, by API in the OpenAI format, with a signed receipt for each model call. Or run any of it on your own hardware.

Decosa API

A key, a first call, a receipt.

The hosted API speaks the OpenAI format, so the SDK or coding agent you already use works. It serves every tool on this site and the open models under them, and each model call comes back with a signed receipt.

Checking the API’s live status…

export DECOSA_API_KEY=dk_...   # from /account/keys

curl https://api.decosa.ai/v1/chat/completions -i \
  -H "Authorization: Bearer $DECOSA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "qwen3.8-27b", "messages": [{"role": "user", "content": "Hello"}]}'

# The answer, and a signed receipt id in the x-decosa-receipt header.

Who serves it

Hosted calls are processed by Decosa's API server, with the open models run by NEAR AI through OpenRouter, with Reka AI as the only fallback under Decosa's account. Each receipt names who served the call; the companies are listed below.

Where your data goes

Credits

One credit is $1 of usage at list price: hosted API calls, the coding agent, Studio and tool runs all draw on the same balance.

$1 a credit, in US dollars. A new key has a free budget of $0.02 of usage a day; a key with credits has no daily cap. At zero, calls stop with HTTP 402 and a link to buy more.

API pricing

Receipts

Each hosted model call is signed with Decosa's Ed25519 key: the model, and hashes of what went in and came out. A receipt shows the record wasn't changed after signing; it holds hashes, not your text.

Verify a run
CompanyWhat it does for DecosaPolicy
OpenRouterRoutes Decosa's hosted language-model calls to NEAR AI (Reka AI as the only fallback), requiring zero data retention and no data collection on every request.Privacy
NEAR AIRuns Qwen3.8-27B in FP8 inside a TEE (a hardware enclave) for the hosted API.Privacy
Reka AIThe only fallback, when NEAR AI is unavailable: Qwen3.8-27B in FP8, keeping no prompts.Privacy
falRenders images and video for UGC ads (the render prompt and inputs); keeps request data 30 days by default, and outputs sit on its CDN for at least 7 days.Privacy

The services that need no GPU run on Decosa's own server: the tools' checkers and lookups, music similarity and beat alignment, Kokoro and Chatterbox speech, and the browser that runs site checks.

Coding agents: start at For AI agents (llms.txt, catalog.json, the MCP server).

The Decosa agent

A private coding agent, and Decosa in the agent you already use

decosa agent is a coding agent on the open Qwen3.8-27B model. Run it on your own GPU and nothing leaves your machine, or use it on Decosa's hosted service with a signed receipt for every call. The same install adds the Decosa tools to Claude Code, Cursor or any MCP client, so they can run a Decosa tool on your input, verify a receipt offline, plan a self-host install or check a GPU box.

1. Install (Python 3.10+)
# The Decosa agent is in early access: ask for it at https://decosa.ai/contact?topic=self-host
2. Run the coding agent (Node 22.19+)
decosa setup && decosa agent
Or add the Decosa tools to Claude Code (Cursor, Codex: see setup)
claude mcp add decosa -e DECOSA_API_KEY=dk_... -- decosa-mcp

Private beta. The install line works for beta accounts with repository access; the public package is waiting on release approval.

What you can ask it

  • Find the right tool for a job and show its working example call
  • Run a tool on your input and save the full output and its receipts
  • Verify a receipt offline against the pinned signing key
  • Plan a self-host install for your GPU: pinned images, models and a smoke test
93%
of 46 Decosa tasks done right by Qwen3.8 with these tools (100% with thinking on)
46%
the same model as a generic agent with our docs and a raw HTTP tool
$0.007
per task at list price, a quarter of the model calls a generic agent makes

Our own eval, 46 tasks written for it, 28 Sep 2026: not a public benchmark. In Claude Code with the MCP server, 4 of 5 hand-run tasks were right the first time. The fifth (can an RTX 4090 run the coding model?) was wrong, and the tool now checks the GPU architecture.

Why developers use Decosa

  • Open models, with receiptsEvery hosted call runs on pinned open weights and comes back with a signed receipt: which model, which weights, a hash of what went in and came out. You can check it yourself, offline.
  • Prove what an endpoint servesPaying for an open model by the token? Check that the endpoint really serves the model and precision you're paying for, with a signed report you can hand to procurement.
  • Run it yourselfEvery tool also ships as a self-host kit: pinned containers, a copy-paste prompt for your coding agent and a smoke test. Your code and data never leave your machine.

Jobs for developers

Make and do

Check and prove

Start to finish

My runs

No runs yet. Open a tool above and run a sample; it will show up here. Runs are saved on this device only.

Building blocks22

Every Decosa tool is made from these. Use them in your own product through the API or the Decosa agent.

Check what a model wrote

  • GroundingChecks each sentence against its sources: supported, partial, unsupported or contradicted, with the span it rests on.API POST /grounding/checkAsk the agent “Check this answer against these sources with Decosa.”Try it, with the request shape →Inside 38 Decosa tools
  • Numeric groundingEvery amount, date, count, span and percentage in a sentence recomputed in code from the table rows it cites; a mismatch comes back with the figure the rows do support.API POST /sar/numbersAsk the agent “Check every number in this draft against the case data.”Try it, with the request shape →Inside 8 Decosa tools
  • Typed judgmentYes/no, one-of-N, score and label questions answered as typed values with a calibrated probability and a receipt.API POST /judgment/judgeAsk the agent “Label these tickets with Decosa's typed judgment and give me the probabilities.”Try it, with the request shape →Inside 28 Decosa tools
  • Small checker modelsTwo small models of our own, Apache-2.0 on Hugging Face, that run on a CPU: citation support (does the cited passage back the sentence?) and note-detail checking (did a drug, dose or date change between transcript and note?).API Hugging Face: decosaaiTry it, with the request shape →

Prove what ran

  • Signed recordA hash chain over every entry, signed with Ed25519, that anyone can re-verify in the browser.API POST /record/verifyAsk the agent “Verify this Decosa record.”Try it, with the request shape →Inside 80 Decosa tools
  • Record AI decisions about peopleA signed, hash-chained record of every automated step your app takes about a person (score, screen, rank, filter, a message sent without approval) and the human decisions after it, holding hashes and your own ids, never personal data. Explain one person's steps in plain words and export a retention log. Open-source TypeScript; nothing is sent to Decosa.API POST /record/verifyAsk the agent “Verify this decision-record export and tell me which entry changed.”Try it, with the request shape →
  • Agent flight recorderA signed, step-by-step record of what a browser or computer-use agent saw, decided and did.API POST /flight/runsAsk the agent “Record this agent run with the Decosa flight recorder.”Try it, with the request shape →Inside 6 Decosa tools
  • Endpoint auditProbes an OpenAI-compatible endpoint for model identity, quality and speed, and signs the verdict.API POST /audit/runsAsk the agent “Audit this endpoint: does it serve the model it claims?”Try it, with the request shape →Inside 2 Decosa tools
  • Content credentialsC2PA credentials and watermarks on rendered files, and a checker for any file.API POST /provenance/checkAsk the agent “Check this image's content credentials.”Try it, with the request shape →Inside 17 Decosa tools

Read, hear and act

  • Document readerPDFs (born-digital or scanned), images, forms and handwriting read into elements with page and box: text in reading order, tables as cells with spans, form fields and checkboxes, and a signed receipt over the page pixels.API POST /docreader/readTry it, with the request shape →Inside 7 Decosa tools
  • Evidence retrievalFinds the passages that answer a question in your documents: an embedder, BM25 and a reranker, each hit a chunk with byte offsets and a Merkle proof into a signed index snapshot.API POST /retrieval/searchTry it, with the request shape →Inside 6 Decosa tools
  • Citation indexLooks up case citations in a local index of public court opinions first (a remote lookup only on a miss), so invented citations are caught without sending the brief out.API Inside POST /preflight/checkAsk the agent “Check the citations in this brief with Decosa.”Try it, with the request shape →Inside 2 Decosa tools
  • Live speech to textStreaming transcription from a microphone or a sample script, sentence by sentence.API POST /lang/transcribeTry it, with the request shape →Inside 11 Decosa tools
  • Speaker diarizationWho said what: transcripts with speakers from recorded audio.Try it, with the request shape →Inside 14 Decosa tools
  • Language packTranslation into all 24 EU official languages with a number lock, the model chosen per language from measured scores: every number, unit, date, code, negation and required term checked in each language's own format, drift flagged with its source span. Speech in consented house voices, speech recognition, and a signed receipt for every model call.API POST /lang/translateTry it, with the request shape →Inside 3 Decosa tools
  • Video understandingOne recording per request to Qwen3.8-27B, sampled at 1 frame a second (up to 240 frames, 32,768 video tokens), answers that cite time ranges, and a receipt whose request hash covers the video's sha256 and the sampling settings.Try it, with the request shape →Inside 2 Decosa tools
  • Form fillingFills a PDF or web form from your own documents, shows the source line for every value, never types passwords or card numbers, and stops before Submit.API POST /fill/pdf/runAsk the agent “Fill this PDF form from these documents with Decosa, and stop before submitting.”Try it, with the request shape →Inside 4 Decosa tools

Make

  • Studio renderMusic, image and video generation on pinned checkpoints, queued, with a seeded render receipt.API POST /studio/jobsTry it, with the request shape →Inside 12 Decosa tools

More

  • Evidence tables from PubMedWhat the trials, meta-analyses and reviews in PubMed found for a supplement and an outcome: one row per study with its PMID, design, n, direction, finding and a quote checked word for word, each finding judged against its own abstract, graded by a published rubric in code, with a signed record.Eval and API →Inside 1 Decosa tools
  • Song starts in long audioWhere each song starts in a mix, a radio show or any long recording, from a tracklist (with or without times), your own track files and the audio itself, on CPU with no model call: a chaptered .m4a, a timestamped tracklist and a signed cue sheet that names the audio's SHA-256.Eval and API →Inside 1 Decosa tools
  • Site checksDeterministic checks for AI answers: robots.txt for AI crawlers by RFC 9309, llms.txt, JSON-LD property by property, and a review-reply guard that never confirms a patient. Open source, in TypeScript and Python.Eval and API →Inside 2 Decosa tools

Self-host prompts92

Each tool has a copy-paste prompt that tells a coding agent how to set it up on your own machine, with a smoke test.

Every self-host prompt
More tools