Attack the signed path that has already merged: src/attack.test.ts #28

Three of the pieces an app's identity rests on are on main — src/sign.ts, src/nonce.ts and client/relay.ts — and nothing yet tries to break them. Write the tests an attacker would, before the door in #8 makes them reachable from the network.

Done looks like

• src/attack.test.ts gathers the attacks in one file, each test named for what it tries and asserting the exact verdict string, so a refusal that quietly becomes a different refusal is visible:
• Identity confusion — a signature made by app a replayed with x-relay-app: b; the app id is inside the canonical string, so this is bad_signature, never ok. And the same app id at a different generation's secret.
• Body confusion — bytes that differ from what was hashed: a trailing newline, the same JSON re-serialised with the keys in another order, \r\n for \n, a zero-width character, and an empty body against a hash of {}.
• Path confusion — /api/events/, /api//events, /api/%65vents, /API/events, and a unicode look-alike: each must fail rather than verify against the real path.
• Field abuse — a timestamp with a leading +, leading zeros, sixteen digits or empty; a nonce at 7, 8, 64 and 65 characters; a nonce carrying +, / or = (base64 rather than base64url); an app id with a capital or a trailing hyphen. Every one is malformed and none of them throws.
• Signature shape — the right length from the wrong secret, a truncated one, one padded to 44 characters, one containing =, and the empty string: all bad_signature, and none of them reaches timingSafeEqual with mismatched lengths.
• Clock — exactly at the window, one millisecond past it in both directions, and a timestamp far in the future; and an assertion that stale is decided before the signature is compared, so an expired request cannot be used as a comparison oracle.
• Replay across rotation — a nonce remembered under one generation stays remembered after the app rotates, because src/nonce.ts keys on the app id and not on the secret.
• Where an attack lands — meaning something is genuinely wrong — the fix goes in the same pull, in the module, and the pull says in a sentence what it was. Where the behaviour is correct but surprising (HMAC accepting a one-byte key and a one-kilobyte key alike), the test says so in a comment so the next reader does not file it as a bug.
• The end of the file lists, as a comment, what cannot be tested from here — the door's status codes, the per-app ration, replay over the network, TLS — naming #8 and #24 as the issues that own them, so the gap is visible rather than assumed covered.
• bun test green, and no production code changes unless an attack found something.

Files: src/attack.test.ts, and src/sign.ts or src/nonce.ts only if something is found

Risks: a test file that restates the happy path in an angrier voice is worse than none — every case has to be one an attacker would actually try, and the file should read as a list of claims about what relay refuses. Never weaken a refusal to make a test pass; if a case is genuinely undecidable, say so in the file.

Suggested: Sentinel — this is the brief exactly: read what merged for replay, injection and unsafe defaults, and leave the findings as something that fails if it ever regresses.

API Error: Can't reach the API server — check your internet or DNS (EAI_AGAIN)

Interrupted, not the work (outage; strike cleared 2026-10-02) — was: Parked by the crew: the run ended without a pull: no changes pushed: API Error: Can't reach the API server — check your internet or DNS (EAI_AGAIN) (api_error)