routstr-core/docs/tinfoil-direct-integration.md

Tinfoil / PPQ Private-Mode Integration Notes

This document summarizes the current options for integrating Tinfoil/PPQ private models with Routstr, based on the EHBP work in this branch and local testing against ppq-private-mode-proxy.

Background

PPQ private models run behind a Tinfoil/EHBP flow:

• Request bodies are HPKE-encrypted by a Tinfoil client.
• The PPQ /private/ endpoint routes ciphertext to the attested enclave.
• The enclave decrypts, runs inference, and returns an encrypted response.
• The caller's Tinfoil client decrypts the response locally.

The PPQ private-mode proxy (~/projects/ppq-private-mode-proxy) uses this pattern with the JavaScript tinfoil SDK:

import { SecureClient } from "tinfoil";

const apiBase = "https://api.ppq.ai";

const client = new SecureClient({
  baseURL: `${apiBase}/private/`,
  attestationBundleURL: `${apiBase}/private`,
  transport: "ehbp",
});

await client.ready();

const response = await client.fetch(`${apiBase}/private/v1/chat/completions`, {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    Authorization: `Bearer ${process.env.PPQ_API_KEY}`,
    "X-Private-Model": "private/gpt-oss-120b",
    "x-query-source": "api",
  },
  body: JSON.stringify({
    model: "gpt-oss-120b", // enclave-internal model id
    messages: [{ role: "user", content: "Hello" }],
  }),
});

const json = await response.json();
console.log(json.usage);

X-Private-Model carries the PPQ-facing private model id, while the encrypted JSON body uses the enclave-internal model id without the private/ prefix.

PPQ private model pricing

PPQ exposes private model pricing through:

GET https://api.ppq.ai/v1/models?type=all

Filter models whose IDs start with private/.

Example private pricing observed:

Model	Input USD / 1M tokens	Output USD / 1M tokens
private/gpt-oss-120b	0.79125	1.31875
private/llama3-3-70b	1.84625	2.90125
private/qwen3-vl-30b	1.31875	4.22
private/glm-5-2	1.5825	5.53875
private/gemma4-31b	0.47475	1.055
private/kimi-k2-6	1.5825	5.53875

The ppq-private-mode-proxy commit ba984214793d3bca0f7d046b6955d42abc1c6843 changed OpenClaw display metadata to align with a 5% API margin. The live PPQ model endpoint returns the more precise rates above, which already include that margin.

Actual PPQ private billing is:

price_usd =
  input_tokens  * input_per_1M_tokens  / 1_000_000
+ output_tokens * output_per_1M_tokens / 1_000_000

A test request to private/gpt-oss-120b produced:

{
  "input_count": 74,
  "output_count": 3,
  "price_in_usd": 0.00006250875
}

which exactly matches:

74 * 0.79125 / 1_000_000 + 3 * 1.31875 / 1_000_000
= 0.00006250875 USD

Integration architectures

There are three materially different ways Routstr could integrate Tinfoil/PPQ private inference.

Option A: User integrates Tinfoil directly

User app / SDK
  -> Tinfoil SecureClient / TinfoilAI
    -> EHBP-encrypted request
      -> Tinfoil/PPQ private enclave

Properties:

• Best privacy for the user.
• Routstr is not in the request path.
• User's client encrypts requests and decrypts responses.
• Usage is visible to the user's app after decryption.
• Billing is handled directly by Tinfoil/PPQ.

Example with Tinfoil's OpenAI-compatible client:

import { TinfoilAI } from "tinfoil";

const client = new TinfoilAI({
  apiKey: process.env.TINFOIL_API_KEY,
  transport: "ehbp",
});

const res = await client.chat.completions.create({
  model: "llama3-3-70b",
  messages: [{ role: "user", content: "Hello" }],
});

console.log(res.choices[0].message.content);
console.log(res.usage);

This is not a Routstr marketplace flow unless Routstr only acts as discovery/UI around direct Tinfoil/PPQ usage.

Option B: Routstr integrates Tinfoil as an upstream client

User -> Routstr plaintext request
  -> Routstr Tinfoil SecureClient encrypts to PPQ/Tinfoil
    -> PPQ private enclave
  -> Routstr receives decrypted response
  -> Routstr bills from decrypted usage
  -> Routstr returns plaintext response to user

Properties:

• Easier exact billing.
• Routstr can read the decrypted OpenAI response and usage object.
• Routstr can charge exact PPQ token pricing.
• Privacy is different: the user sends plaintext to Routstr, and Routstr sees prompts/responses.
• End-to-end encryption is only Routstr-to-enclave, not user-to-enclave.

This should be considered a separate product/provider mode, not the same as an end-to-end private relay.

Practical implementation options:

1. Run a Node sidecar that uses the tinfoil npm package and expose it as a local HTTP upstream to Routstr.
2. Port EHBP client behavior to Python.
3. Reuse or adapt ppq-private-mode-proxy as a local upstream.

A Node sidecar is probably the quickest implementation path because ppq-private-mode-proxy already demonstrates the full flow.

Option C: Routstr uses Tinfoil as a direct blind upstream

This is the current branch's design intent and is likely the best fit if Tinfoil/PPQ exposes usage metadata headers:

User Tinfoil SecureClient
  -> encrypted request body
    -> Routstr proxy
      -> Tinfoil/PPQ private API
         with X-Tinfoil-Request-Usage-Metrics: true
        -> PPQ private enclave
      <- encrypted response
         plus X-Tinfoil-Usage-Metrics / cost headers
    <- Routstr proxy
  -> user decrypts response

In this mode Routstr is still a normal upstream proxy from the user's point of view, but the upstream is Tinfoil/PPQ private inference and the body remains opaque to Routstr.

Properties:

• Strongest privacy with Routstr in the path.
• Routstr never sees plaintext prompt or plaintext response.
• Routstr can authenticate and route based on plaintext headers.
• Routstr should request Tinfoil usage metadata by adding X-Tinfoil-Request-Usage-Metrics: true to the upstream request.
• Tinfoil documents X-Tinfoil-Usage-Metrics as an upstream response header for non-streaming requests.
• For streaming requests, Tinfoil documents X-Tinfoil-Usage-Metrics as an HTTP trailer available only after the response body completes.
• If Tinfoil/PPQ returns X-Tinfoil-Usage-Metrics or a cost header on the encrypted response, Routstr can bill exactly without decrypting the body.
• If usage is only present inside the encrypted response body, Routstr still cannot read it and exact billing is not possible without a separate metadata path.

This is the only architecture that preserves end-to-end encryption from the user to the PPQ/Tinfoil enclave while still letting Routstr mediate payment. The key requirement is that usage/cost metadata must be returned outside the encrypted body, ideally as a response header available before body streaming begins.

Current Routstr problem

The current EHBP implementation charges successful EHBP requests at max_cost_for_model because Routstr cannot decrypt the response body:

successful EHBP request -> charge full reserved max cost

That is incorrect for PPQ private models. Max cost should be only a reservation/solvency ceiling. Final charge should use actual PPQ private token pricing.

Desired behavior:

reserve max cost
forward encrypted request
obtain actual usage/cost metadata
finalize actual cost
refund/release the difference

Usage/cost metadata requirement

For blind-relay exact billing, PPQ should return one of the following outside the encrypted response body:

X-PPQ-Cost-USD: 0.00006250875

or:

X-Private-Usage-Metrics: input=74,output=3

or:

X-Tinfoil-Usage-Metrics: prompt=74,completion=3,total=77

Tinfoil proxy documentation references a usage-metrics flow where a proxy can request usage via:

X-Tinfoil-Request-Usage-Metrics: true

and read usage from:

X-Tinfoil-Usage-Metrics

Docs/example references:

• https://docs.tinfoil.sh/guides/proxy-server
• https://github.com/tinfoilsh/encrypted-request-proxy-example

During local PPQ testing, PPQ responses included this CORS exposure header:

Access-Control-Expose-Headers: Ehbp-Response-Nonce, X-Private-Usage-Metrics, X-Encrypted-Usage-Metrics, X-Tinfoil-Usage-Metrics

However, the actual tested non-streaming response did not include any of these usage headers, even when X-Tinfoil-Request-Usage-Metrics: true was sent.

The decrypted body did include normal OpenAI usage, but only the decrypting Tinfoil client can see that body.

Query-history fallback

PPQ's query history endpoint exposes actual usage and cost:

GET https://api.ppq.ai/queries/history?page=1&page_count=...

A record includes:

{
  "timestamp": "...",
  "model": "private/gpt-oss-120b",
  "input_count": 74,
  "output_count": 3,
  "price_in_usd": 0.00006250875,
  "query_type": "chat_completion",
  "query_source": "api"
}

This could be used as a fallback, but it is less robust than response headers/trailers because matching a request to a history row can be race-prone under concurrency. It would need a reliable request identifier or metadata field that PPQ stores in history.

Recommended Routstr direction

Use Tinfoil/PPQ as a direct blind upstream and have Routstr explicitly request usage metadata:

User encrypts body
Routstr reserves max cost
Routstr forwards encrypted body to Tinfoil/PPQ /private/
Routstr includes X-Tinfoil-Request-Usage-Metrics: true
Tinfoil/PPQ returns X-Tinfoil-Usage-Metrics as a response header for non-streaming,
or as an HTTP trailer after the body completes for streaming
Routstr finalizes exact charge
User decrypts encrypted response

This preserves both:

• privacy: Routstr cannot read prompts/responses;
• exact billing: Routstr can charge actual PPQ private model cost, assuming Tinfoil/PPQ returns usage/cost metadata outside the encrypted body.

Implementation steps:

1. Update PPQ model fetching to include private models:

   GET https://api.ppq.ai/v1/models?type=all
   

2. Register private/* models and any Routstr-facing aliases with correct forwarded_model_id.

3. Keep max-cost reservation for bearer keys and X-Cashu solvency checks.

4. Add parsing support for possible usage/cost headers:

   X-PPQ-Cost-USD
   X-Private-Usage-Metrics
   X-Tinfoil-Usage-Metrics
   X-Encrypted-Usage-Metrics
   

5. Finalize by actual cost instead of max cost:

   actual_msats = ceil((actual_usd / sats_usd_price()) * 1000)
   actual_msats = max(actual_msats, settings.min_request_msat)
   actual_msats = min(actual_msats, reserved_msats)
   

   or, if only token counts are available:

   actual_usd =
     input_tokens  * input_per_1M_tokens  / 1_000_000
   + output_tokens * output_per_1M_tokens / 1_000_000
   

6. If usage/cost metadata is missing, choose an explicit policy:

   • fail closed and refund/revert;
   • query PPQ history as a fallback;
   • fallback to max-cost billing only if explicitly configured and clearly disclosed.

Silent max-cost billing should not be the default for PPQ private requests.

X-Cashu consideration

For bearer-auth requests, finalization can happen after the response stream completes if usage is delivered as a trailer.

For X-Cashu, Routstr needs to return the refund token in the response headers. If usage/cost is only available after consuming the encrypted response stream, Routstr may need to buffer EHBP responses before sending them to the client so it can compute the refund amount first.

Possible approaches:

1. Prefer a non-trailer response header with actual cost, available before streaming body starts.
2. Buffer EHBP X-Cashu responses and then return X-Cashu refund.
3. Introduce a later/refund-claim mechanism, which would be a larger protocol change.

Summary

• PPQ private models are billed per actual input/output tokens.
• Private model rates are available from GET /v1/models?type=all.
• Current Routstr EHBP billing at max cost is wrong for PPQ private models.
• Direct Tinfoil integration inside Routstr would enable exact usage billing but would make Routstr see plaintext.
• A blind EHBP relay preserves privacy but requires PPQ/Tinfoil to expose usage/cost in plaintext headers/trailers.
• The preferred solution is to keep Routstr blind and have PPQ return billing metadata outside the encrypted body.

Implementation status

Direct Tinfoil upstream integration is implemented in routstr/upstream/tinfoil.py and routstr/upstream/ehbp.py.

What was built

• TinfoilUpstreamProvider (provider_type = "tinfoil"):

  • Base URL: https://inference.tinfoil.sh
  • Fetches models from the public GET /v1/models endpoint (no auth needed).
  • Parses Tinfoil's pricing (inputTokenPricePer1M, outputTokenPricePer1M, requestPrice) into the standard Model/Pricing schema.
  • supports_ehbp = True — acts as a blind EHBP relay.
  • get_ehbp_forwarding_target() returns a target that includes X-Tinfoil-Request-Usage-Metrics: true.
  • forward_get_request() proxies /attestation to https://atc.tinfoil.sh/attestation so the SDK can fetch attestation bundles through Routstr.
  • Registered in routstr/upstream/__init__.py and seeded from TINFOIL_API_KEY env var.

• routstr/upstream/ehbp.py:

  • parse_tinfoil_usage_metrics() parses prompt=N,completion=N[,total=N][,model=<name>] into an OpenAI-style usage dict. The model field (added in tinfoilsh/confidential-model-router PR #385) is extracted as a string.
  • _resolve_ehbp_target_url() overrides the forwarding URL with X-Tinfoil-Enclave-Url when the SDK sends it.
  • _strip_proxy_headers() removes X-Routstr-Model, X-Tinfoil-Enclave-Url, and X-Tinfoil-Request-Usage-Metrics before forwarding to the enclave.
  • _compute_ehbp_actual_cost() converts the usage header into msats via calculate_cost(), clamped to [min_request_msat, max_cost_for_model]. When the header's model=<name> differs from the requested model, the actual served model's pricing is used for cost calculation.
  • forward_ehbp_request() (bearer auth): if X-Tinfoil-Usage-Metrics is present in the response header, finalizes with adjust_payment_for_tokens() for exact billing; otherwise falls back to max-cost. Billing uses the actual served model when it differs from the requested one.
  • forward_ehbp_x_cashu_request(): if usage is available, computes the refund from actual cost instead of max cost, using the actual served model's pricing when applicable.

• routstr/proxy.py: /attestation and /tee/attestation paths are forwarded to Tinfoil upstreams without model/cost/auth lookups.

Billing behavior

Request shape	Usage source	Billing
Bearer, non-streaming	X-Tinfoil-Usage-Metrics response header	Exact token cost via adjust_payment_for_tokens
Bearer, streaming	X-Tinfoil-Usage-Metrics HTTP trailer	Exact token cost (h11 captures trailers)
Bearer, no usage header/trailer	N/A	Max-cost fallback
X-Cashu, non-streaming	X-Tinfoil-Usage-Metrics response header	Refund = redeemed - actual_cost
X-Cashu, streaming	X-Tinfoil-Usage-Metrics HTTP trailer	Refund = redeemed - actual_cost (h11 captures trailers)
X-Cashu, no usage header/trailer	N/A	Refund = redeemed - max_cost

Cost response headers

Since EHBP response bodies are opaque encrypted blobs, per-request cost cannot be injected into the JSON body (as done in the normal proxy flow). Instead, Routstr returns cost info as response headers:

Header	Auth	Description
X-Routstr-Cost-Msats	Bearer, X-Cashu	Total msats charged for this request
X-Routstr-Cost-Usd	Bearer	USD equivalent of the charge
X-Routstr-Input-Cost-Msats	Bearer, X-Cashu	msats attributed to input tokens
X-Routstr-Output-Cost-Msats	Bearer, X-Cashu	msats attributed to output tokens

The client/Tinfoil SDK can read these headers from the HTTP response without needing to decrypt the body.

Setup

TINFOIL_API_KEY=your-tinfoil-api-key

The provider is auto-seeded on first startup.

Usage metrics header format

Tinfoil returns usage metrics in the X-Tinfoil-Usage-Metrics response header (non-streaming) or HTTP trailer (streaming) when X-Tinfoil-Request-Usage-Metrics: true is sent. As of tinfoilsh/confidential-model-router PR #385, the format is:

prompt=<prompt_tokens>,completion=<completion_tokens>,total=<total_tokens>,model=<served_model>

The model field carries the actual model name served by the enclave. Routstr uses this to:

• Verify the served model matches the expected upstream model. The comparison uses model_obj.forwarded_model_id (the actual upstream ID, e.g. glm-5-2) rather than model_obj.id (the client-facing alias, e.g. tinfoil-glm-5-2), so aliased models don't trigger a spurious mismatch.
• When they genuinely differ (Tinfoil served a different upstream model than expected), look up the actual served model's pricing and use it for billing. The reverse lookup uses get_model_instance, which resolves forwarded_model_id values registered as routable aliases.
• Log the discrepancy for observability.

If the actual model is not found in Routstr's model registry, billing falls back to the requested model's pricing.

What still needs verification

• End-to-end test with a real Tinfoil SDK client against a Routstr node with TINFOIL_API_KEY set. Verified: both non-streaming (header) and streaming (trailer) responses include model=<name>.
• Streaming trailer capture is implemented by buffering the encrypted response in forward_with_trailer() and then using the dedicated EHBP payment finalizers for bearer and X-Cashu requests. This provides actual-cost billing today, at the cost of full time-to-last-byte latency for streaming responses.
• Whether Tinfoil's /v1/responses endpoint also returns usage metrics headers or trailers.