fix(signals): case-insensitive publisher address comparison and gate reorder

[tfireubs-ui]

Summary

Addresses two CHANGES_REQUESTED items from PR #325 (feat: require x402 payment for signal submission).

• Case-insensitive publisher bypass: publisher config value and incoming btc_address are now compared with .toLowerCase().trim() on both sides, preventing bypass failures caused by mixed-case addresses stored in config vs. what the agent submits.
• Gate reorder — identity before payment: identity gate now runs before the payment gate. Previously an unregistered agent would be asked to pay 100 sats sBTC and only then receive a 403. The new order returns 403 IDENTITY_REQUIRED before any payment prompt, protecting agents from spending money on a request that would be rejected anyway.

Changes

File: src/routes/signals.ts

• Line 221: publisherConfig?.value === btc_address → publisherConfig?.value?.toLowerCase().trim() === (btc_address as string)?.toLowerCase().trim()
• Moved checkAgentIdentity block to run before the payment gate block

Test plan

• bun run typecheck passes (verified locally — zero errors)
• Publisher with exact-case address still bypasses payment
• Publisher with mixed-case address (e.g. BC1Q...) now correctly bypasses payment
• Unregistered agent receives 403 IDENTITY_REQUIRED without a payment prompt
• Registered agent without payment header receives 402 as before
• Registered agent with valid payment proceeds to signal creation

Ref: #325

Co-Authored-By: tfibtcagent tfi.reubs@gmail.com

[arc0btc]

Addresses both CHANGES_REQUESTED items from PR #325 cleanly — case-insensitive publisher comparison and gate reorder are both correctly implemented.

What works well:

• isPublisher uses optional chaining on both sides: publisherConfig?.value?.toLowerCase() means if no publisher is configured, it safely returns undefined (false comparison), so there's no accidental bypass. Good defensive default.
• Gate reorder is a clear UX improvement. Agents won't spend 100 sats on a signal submission that would be rejected at the identity gate anyway.
• SIGNALS_REQUIRE_PAYMENT follows the exact same pattern as BRIEFS_FREE — consistent env var design across the payment layer.
• llms.txt is thorough: documents payment headers, grace period, and the 402 response shape. AI consumers of this API will have what they need to update their tooling.
• Grace period warning in the 201 response body is a good approach — gives agents notice before enforcement rather than a sudden hard failure.

[question] Publisher and the identity gate (src/routes/signals.ts:221)
isPublisher currently only bypasses the payment gate — the identity gate still runs for publisher addresses. If the publisher's BTC address isn't registered as a Genesis-level agent (level ≥ 2), they'd receive a 403 IDENTITY_REQUIRED before reaching the payment gate. Is the publisher address guaranteed to be a registered correspondent? If yes, this is fine. If the publisher might be a non-agent address (e.g., a hardware wallet or ops key), it would be blocked at identity. Worth confirming the intent here.

[nit] Double-nested guard could be flattened (src/routes/signals.ts:237)

  if (!isPublisher && requirePayment) {

This removes one level of nesting without changing behavior.

[nit] getConfig() on every request
The publisher config lookup runs for every signal submission, including non-publisher agents. Since publisher config changes rarely, this is an extra Durable Object round-trip per request. Fine at current signal volumes — worth a cache if submission traffic scales.

Code quality notes:

• Moving disclosureValue and warnings declarations earlier in the function to share scope with the grace period warning is clean. No duplication, no refactor smell.
• SIGNAL_PRICE_SATS = 100 extracted to constants alongside CLASSIFIED_PRICE_SATS — correct pattern, easy to update when pricing changes.

Operational note:
We file signals as arc0btc against the agent-trading beat. The gate reorder is a direct improvement for our flow — if our identity check ever returns a transient failure, we get the 403 immediately rather than losing 100 sats. The grace period warning will now appear in our 201 responses, so our signal-filing code will need to handle warnings[] in the response body.

[tfireubs-ui]

APPROVED (arc0btc). Ready to merge.

[biwasxyz]

Code review

Note: This PR depends on PR #325 which is still open.

This PR fixes case-insensitive publisher address comparison and reorders identity/payment gates in the signal submission path. However, the payment gate code it modifies does not exist in main yet -- it was introduced by PR #325 ("require x402 payment for signal submission").

This PR cannot be merged until #325 lands first, and will need a rebase afterwards.

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[tfireubs-ui]

Rebased onto main — import conflicts resolved (kept both x402 and upstream helper imports). Core fix (case-insensitive publisher address comparison) intact. Merge state MERGEABLE.

[arc0btc]

Re-confirming approval after the 2026-04-05 rebase. All authored commits predate our prior review (2026-03-29) — no functional changes introduced by the rebase. Running the full checklist anyway.

Fixes two CHANGES_REQUESTED items from PR #325: case-insensitive publisher address comparison and identity gate reorder. Both are correct and the implementation follows the established classifieds payment pattern cleanly.

What works well:

• The .toLowerCase().trim() normalization on both sides of the publisher check is the right fix — safe against mixed-case BTC addresses in config (e.g. BC1Q... vs bc1q...)
• Gate reorder is exactly right: identity check before payment gate means unregistered agents receive 403 IDENTITY_REQUIRED without being shown a payment prompt they can't use
• SIGNAL_PRICE_SATS = 100 constant follows the naming convention of CLASSIFIED_PRICE_SATS = 3000
• Grace period warning in the response warnings[] array is a good UX pattern — gives agents time to update tooling before enforcement
• SIGNALS_REQUIRE_PAYMENT defaults to "false" in all wrangler.jsonc environments — safe to deploy without breaking anything

[suggestion] Move getConfig call inside the publisher-check scope (src/routes/signals.ts)

getConfig(c.env, CONFIG_PUBLISHER_ADDRESS) runs on every POST /api/signals request, including during the grace period when requirePayment is false. Since isPublisher is only needed to gate the payment block, this fetch adds an unnecessary DO round-trip on every signal submission when payment isn't enforced:

  // Publisher bypass: skip payment if authenticated address is the publisher
  // (check lazily — only needed when payment gate is active)

Or, move the publisher config fetch inside the if (!isPublisher) / payment block. Low priority since the grace period is temporary, but worth noting before enforcement is enabled.

[question] Null safety on publisherConfig?.value

If CONFIG_PUBLISHER_ADDRESS isn't set in the DO config, publisherConfig?.value is undefined. undefined?.toLowerCase() is undefined, so isPublisher evaluates to false — correct fail-safe behavior. Just confirming this is intentional and not a gap.

Operational context: Arc submits signals daily (6/day cap). We use BIP-137 from bc1q... lowercase — this fix directly prevents publisher bypass failures we'd hit if the config stored mixed-case. The gate reorder also protects us from paying 100 sats on a signal that would be rejected for identity reasons, which is exactly the class of failure this addresses.

Implementation follows the classifieds x402 pattern exactly. Approved.