feat(#375): sdk_parity_fixtures for the wrapper — 12 live tags the spec never had

[dcccrypto]

Part 2 of 3 for #375. The percolator-prog target of the Parity Gate has failed with cargo run failed on every run since at least 2026-08-23, for two stacked reasons: this binary did not exist, and the job never checked out the percolator engine that this crate compiles through path = "../percolator". The workflow half is in the percolator-sdk PR.

What the gate finds the moment it can run

percolator-sdk/specs/wrapper-tags.json is missing twelve live instructions, tags 81–92:

tag	instruction		tag	instruction
81	CancelRedemption		87	WithdrawInsuranceReserveToStake
82	UnwrapEscrowedPortfolio		88	UpdateMaintenanceFeePerSlot
83	InitMatcherCtx		89	ExpireBackingBucket
84	WithdrawProtocolFee		90	WithdrawCreatorFee
85	SetProtocolFeeAuthority		91	RebalanceLpVaultBacking
86	UpdateFeeSplit		92	UpdateInsuranceWithdrawPolicy

Seven of those move money. IX_TAG already carried 83–92 so the SDK could encode them; CancelRedemption(81) and UnwrapEscrowedPortfolio(82) were genuinely absent from the SDK, and tags 81/82 were annotated there as "Not in v17" — false.

Everything else already agreed: the gaps list comes back identical, with no name mismatches and no phantom tags.

Why this probes decode instead of reading the source

The obvious implementation parses the match tag arms. Do not.

Writing this, a regex over N => Self::Variant reported 69 tags and concluded that BatchTradeNoCpi(66), BatchTradeCpi(67) and InitMatcherCtx(83) did not exist — that the SDK had invented two of them. All three exist. They are dispatched in block form (66 => { ... }), which the pattern silently skipped. A parser that is wrong about the dispatcher produces a spec that is confidently wrong, which is worse than no gate at all.

Probing Instruction::decode cannot make that mistake — the answer comes from the code path the runtime uses.

A first draft then capped the probe at 200 bytes and reported tag 0 as unallocated, because InitMarket's body is 218. There is now a canary asserting tag 0 decodes, so that failure cannot ship quietly either.

Four names are deliberately the SDK's

Tags 3/4/5/8 emit DepositCollateral, WithdrawCollateral, KeeperCrank, CloseAccount. Not drift: none has appeared in this crate at any commit, they are declared aliases in the SDK (@alias DepositCollateral @since v12.x alias), and test/parity-fixtures.test.ts keys on them. Renaming four entries of the SDK's public surface would fix nothing — this gate catches a tag being renumbered or an instruction appearing/disappearing, and the tag binding is discovered by probing either way. Renaming a variant in the program still breaks the build at the match arm.

The deployed artifact is untouched

cargo build-sbf --features devnet produces a byte-identical percolator_prog.so with and without this file:

without bin: 9a310e287001e620174c271e6712322d4145161998e84cbb85b0f8e4c16942fb
with bin:    9a310e287001e620174c271e6712322d4145161998e84cbb85b0f8e4c16942fb

Checked with the file genuinely moved out of the tree, not stashed.

Upstream aeyakovenko/percolator-prog has no src/bin at all — nothing to coordinate.

🤖 Generated with Claude Code

https://claude.ai/code/session_01NgoNgagkvw7i5SSRC3FJ8D

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