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Ministack

27304b7b6d09 21 recorded runs

86.6%
correct, across 873 of 873 operations
Tier 1 91.0%
Tier 2 81.9%
Tier 3 82.0%

Fully supports

Operation areas this target implements completely - every test passes, nothing skipped. Areas it only partly implements, or gets wrong, are in “Where it falls short” below.

  • batchGetItem tier 1
  • deleteItem tier 1
  • deleteTable tier 1
  • describeTable tier 1
  • listTables tier 1
  • updateTable tier 1
  • account tier 2
  • backups tier 2
  • contributorInsights tier 2
  • export tier 2
  • kinesis tier 2
  • resourcePolicy tier 2
  • streams tier 2
  • tags tier 2
  • ttl tier 2
  • updateTable tier 2
  • legacy-api tier 3

Conformance over time

Ministack conformance history, 2026-04-27 to 2026-07-13 55% 78% 100% 62.4% 27 Apr 68.4% 23 May 66.1% 24 May 65.5% 25 May 65.1% 26 May 87.0% 29 May 97.4% 9 Jun 97.4% 16 Jun 97.4% 18 Jun 97.4% 19 Jun 96.6% 21 Jun 91.0% 22 Jun 90.1% 23 Jun 90.0% 24 Jun 89.4% 27 Jun 89.4% 29 Jun 89.0% 30 Jun 86.5% 1 Jul 86.5% 2 Jul 86.5% 6 Jul 86.6% 13 Jul

Where it falls short

Operation groups with gaps in the latest run, biggest first. Unsupported means the target doesn't implement that feature at all, often by design. Open one for the exact tests, or see the conformance suite.

  • error-messages Tier 3 42 failing
    View these tests in the suite →
    • BatchGetItem - exact error messages empty-binary lookup key: full empty-value message
    • BatchGetItem - exact error messages mixing ProjectionExpression on one table and AttributesToGet on another is rejected
    • BatchWriteItem - exact error messages empty-binary delete-request key: full empty-value message
    • BatchWriteItem - exact error messages wrong-typed index key: full type-mismatch message
    • BatchWriteItem - exact error messages non-scalar index key: full type-mismatch message
    • BatchWriteItem - exact error messages empty-string index key: full secondary-index-key message
    • BatchWriteItem - exact error messages empty-binary index key: full secondary-index-key message
    • CreateTable - exact error messages PAY_PER_REQUEST with ProvisionedThroughput: full conflict message
    • CreateTable - exact error messages GSI INCLUDE projection without NonKeyAttributes: full missing-attributes message
    • CreateTable - exact error messages LSI INCLUDE projection without NonKeyAttributes: full missing-attributes message
    • CreateTable - exact error messages StreamSpecification StreamEnabled:false with a StreamViewType: full conflict message
    • DeleteItem - exact error messages empty-binary key value: full ValidationException message
    • GetItem - exact error messages empty-binary key value: full ValidationException message
    • PutItem - exact error messages NULL attr with false is accepted and normalises to NULL true
    • PutItem - exact error messages empty-binary index key value: full secondary-index-key message
    • Query - exact error messages Select SPECIFIC_ATTRIBUTES without ProjectionExpression: full required-projection message
    • Scan - exact error messages Select SPECIFIC_ATTRIBUTES without ProjectionExpression: full required-projection message
    • TransactWriteItems - exact error messages Put wrong-typed table key: cancelled with full ValidationError reason
    • TransactWriteItems - exact error messages Put non-scalar table key: cancelled with full ValidationError reason
    • TransactWriteItems - exact error messages Put wrong-typed index key: cancelled with full ValidationError reason
    • TransactWriteItems - exact error messages Put non-scalar index key: cancelled with full ValidationError reason
    • TransactWriteItems - exact error messages Update wrong-typed index key: cancelled with full ValidationError reason
    • TransactWriteItems - exact error messages Update non-scalar index key: cancelled with full ValidationError reason
    • TransactWriteItems - exact error messages Put empty-string table key: top-level ValidationException
    • TransactWriteItems - exact error messages Put empty-string index key: top-level ValidationException
    • TransactWriteItems - exact error messages Update empty-string index key: top-level ValidationException
    • TransactWriteItems - exact error messages Update empty-string Key: top-level empty-value message
    • TransactWriteItems - exact error messages Delete empty-string Key: top-level empty-value message
    • TransactWriteItems - exact error messages ConditionCheck empty-string Key: top-level empty-value message
    • TransactWriteItems - exact error messages Update wrong-typed Key: cancelled with schema-mismatch reason
    • TransactWriteItems - exact error messages Update non-scalar Key: cancelled with schema-mismatch reason
    • TransactWriteItems - exact error messages Delete wrong-typed Key: cancelled with schema-mismatch reason
    • TransactWriteItems - exact error messages Delete non-scalar Key: cancelled with schema-mismatch reason
    • TransactWriteItems - exact error messages ConditionCheck wrong-typed Key: cancelled with schema-mismatch reason
    • TransactWriteItems - exact error messages ConditionCheck non-scalar Key: cancelled with schema-mismatch reason
    • TransactWriteItems - exact error messages Put empty-binary item key: top-level empty-value message
    • TransactWriteItems - exact error messages Update empty-binary Key: top-level empty-value message
    • TransactWriteItems - exact error messages Delete empty-binary Key: top-level empty-value message
    • TransactWriteItems - exact error messages ConditionCheck empty-binary Key: top-level empty-value message
    • TransactWriteItems - exact error messages Put empty-binary index key: top-level ValidationException
    • TransactWriteItems - exact error messages Update empty-binary index key: top-level ValidationException
    • UpdateItem - exact error messages empty-binary index key value: full secondary-index-key message
  • transactions Tier 2 19 failing
    View these tests in the suite →
    • TransactWriteItems - validation Put with a wrong-typed table key cancels with a ValidationError reason
    • TransactWriteItems - validation Put with a non-scalar table key cancels with a ValidationError reason
    • TransactWriteItems - validation Put with a wrong-typed index key cancels with a ValidationError reason
    • TransactWriteItems - validation Put with a non-scalar index key cancels with a ValidationError reason
    • TransactWriteItems - validation Update setting a wrong-typed index key cancels with a ValidationError reason
    • TransactWriteItems - validation Update setting a non-scalar index key cancels with a ValidationError reason
    • TransactWriteItems - validation Put with an empty-string table key is a top-level ValidationException
    • TransactWriteItems - validation Put with an empty-string index key is a top-level ValidationException
    • TransactWriteItems - validation Update setting an empty-string index key is a top-level ValidationException
    • TransactWriteItems - validation Update with an empty-string Key is a top-level ValidationException
    • TransactWriteItems - validation Delete with an empty-string Key is a top-level ValidationException
    • TransactWriteItems - validation ConditionCheck with an empty-string Key is a top-level ValidationException
    • TransactWriteItems - validation Update with a wrong-typed Key cancels with a ValidationError reason
    • TransactWriteItems - validation Update with a non-scalar Key cancels with a ValidationError reason
    • TransactWriteItems - validation Delete with a wrong-typed Key cancels with a ValidationError reason
    • TransactWriteItems - validation Delete with a non-scalar Key cancels with a ValidationError reason
    • TransactWriteItems - validation ConditionCheck with a wrong-typed Key cancels with a ValidationError reason
    • TransactWriteItems - validation ConditionCheck with a non-scalar Key cancels with a ValidationError reason
    • TransactWriteItems - ConsumedCapacity: conditional, check, replay, cancel reports write capacity on the first call and read capacity on a same-token replay
  • scan Tier 1 12 failing
    View these tests in the suite →
    • Scan - GSI scans a GSI with ALL projection and returns all attributes
    • Scan - GSI scans a GSI with INCLUDE projection and returns only projected attributes
    • Scan - GSI sparse composite GSI: an item missing the GSI range key is not scanned
    • Scan - GSI pagination returns all items across paginated GSI scan
    • Scan - GSI pagination returns all matching items with filter across paginated GSI scan
    • Scan - GSI pagination across tied sort keys walks every item once across a paged GSI scan with tied sort keys
    • Scan - LSI pagination under duplicate cursor components returns all items across paginated LSI scan
    • Scan - LSI pagination under duplicate cursor components returns all matching items with filter across paginated LSI scan
    • Scan - Select / ProjectionExpression rejections Select ALL_ATTRIBUTES with ProjectionExpression is rejected
    • Scan - Select / ProjectionExpression rejections Select ALL_PROJECTED_ATTRIBUTES without an IndexName is rejected
    • Scan - Select / ProjectionExpression rejections Select COUNT with ProjectionExpression is rejected
    • Scan - Select / ProjectionExpression rejections Select ALL_PROJECTED_ATTRIBUTES with ProjectionExpression and no IndexName is rejected
  • putItem Tier 1 9 failing
    View these tests in the suite →
    • PutItem - ConditionExpression rejects a BETWEEN with reversed bounds at parse time
    • PutItem - number format rejects "1_000"
    • PutItem - number format rejects " 5"
    • PutItem - number format rejects "5 "
    • PutItem - validation rejects a wrong-typed index key attribute
    • PutItem - validation rejects a non-scalar index key attribute
    • PutItem - validation rejects an empty-string index key attribute
    • PutItem - validation rejects a number with a leading space
    • PutItem - validation rejects a number with a trailing space
  • partiql Tier 2 9 failing
    View these tests in the suite →
    • ExecuteStatement - PartiQL SELECT with nested map path
    • ExecuteStatement - PartiQL SELECT with begins_with in WHERE clause
    • ExecuteStatement - PartiQL PartiQL UPDATE with REMOVE
    • ExecuteStatement - PartiQL evaluates negated predicates (NOT begins_with, IS NOT MISSING)
    • ExecuteStatement - PartiQL DELETE with a false NOT begins_with predicate fails ConditionalCheckFailed
    • ExecuteStatement - PartiQL DELETE with a true NOT begins_with predicate removes the item
    • ExecuteStatement - PartiQL rejects a write WHERE clause that omits the primary key
    • ExecuteStatement - PartiQL DELETE on a missing key with a non-key predicate is a silent no-op
    • ExecuteTransaction - PartiQL idempotent replay under the same ClientRequestToken does not double-apply
  • query Tier 1 7 failing
    View these tests in the suite →
    • Query - GSI sparse composite GSI: an item with the GSI hash key but no range key is excluded
    • Query - KeyConditionExpression semantics rejects a nested path on a key attribute
    • Query - LSI sparse LSI: an item missing the LSI sort key is excluded but stays in the base table
    • Query - Select / ProjectionExpression rejections Select ALL_ATTRIBUTES with ProjectionExpression is rejected
    • Query - Select / ProjectionExpression rejections Select ALL_PROJECTED_ATTRIBUTES without an IndexName is rejected
    • Query - Select / ProjectionExpression rejections Select COUNT with ProjectionExpression is rejected
    • Query - Select / ProjectionExpression rejections Select ALL_PROJECTED_ATTRIBUTES with ProjectionExpression and no IndexName is rejected
  • limits Tier 3 6 failing
    View these tests in the suite →
    • Key-value length limits rejects a partition key over the 2048-byte limit on write
    • Key-value length limits rejects an over-limit partition key on the read path
    • Nesting depth - 32-level document limit rejects a stored attribute nested 32 levels (leaf at level 33)
    • Nesting depth - 32-level document limit rejects a 32-level ExpressionAttributeValue with ValidationException
    • Response size limit (1MB) Query returns LastEvaluatedKey when response would exceed 1MB
    • Response size limit (1MB) Scan returns LastEvaluatedKey when response would exceed 1MB
  • createTable Tier 1 4 failing
    View these tests in the suite →
    • CreateTable - validation rejects a GSI INCLUDE projection without NonKeyAttributes
    • CreateTable - validation rejects StreamSpecification with StreamEnabled false plus a StreamViewType
    • CreateTable - LSI rejects an LSI INCLUDE projection without NonKeyAttributes
    • CreateTable - index and stream spec validation rejects a KEYS_ONLY GSI projection carrying NonKeyAttributes
  • getItem Tier 1 4 failing
    View these tests in the suite →
    • ConsumedCapacity - single-item ops report only the aggregate, no read/write split an eventually-consistent GetItem reports 0.5 CapacityUnits and no read/write split
    • GetItem - projection validation and fidelity rejects overlapping projection paths (a and a.b)
    • GetItem - projection validation and fidelity rejects duplicate projection paths (a and a)
    • GetItem - projection validation and fidelity projects multiple list indices compacted and index-ordered
  • batchWriteItem Tier 1 3 failing
    View these tests in the suite →
    • BatchWriteItem - validation rejects a wrong-typed index key value
    • BatchWriteItem - validation rejects a non-scalar index key value
    • BatchWriteItem - validation rejects an empty-string index key value
  • updateItem Tier 1 1 failing
    View these tests in the suite →
    • UpdateItem - ReturnValues granularity UPDATED_NEW on a nested SET returns only the changed fragment
  • validation-ordering Tier 3 1 failing
    View these tests in the suite →
    • UpdateItem - validation ordering rejects invalid ReturnValues (UpdateItem reports the first enum error)

Run history

Run Total Movement
86.6% +0.1pp rose 0.1 percentage points
86.5% 0.0pp unchanged
86.5% 0.0pp unchanged

Suite on

Grew to 873 tests, up 49, all characterised against real DynamoDB in eu-west-2. New coverage in three areas:

  • ConsumedCapacity: the transactional read/write split on a same-token replay and on ExecuteTransaction, and a correction that single-item operations report the aggregate CapacityUnits and omit the split, which is transactional-only.
  • Empty-binary key values: rejected as a top-level ValidationException on every path, including secondary-index keys and inside transactions, mirroring the empty-string rejection.
  • Expression, limit and response-shape parity: KeyConditionExpression operand and nested-path rules, ExpressionAttributeNames/Values hygiene, projection validation and list-index fidelity, reversed-bounds BETWEEN, read-path key-length and segment caps, whitespace numbers, batch unprocessed fields and cross-table projection mixing, the bare no-op upsert, multi-subpath UPDATED_NEW, filter operand ordering, hash-only-GSI pagination, and CreateTable spec validation.
 		86.5% -2.5pp fell 2.5 percentage points

Suite on

Grew to 824 tests, up 7, in two parts: two sibling-parity gaps where one half of a rule was pinned and the other was not, and the capacity accounting of conditional and idempotent transactional writes. All characterised against real DynamoDB in eu-west-2.

The first covers the LSI side of the INCLUDE-projection-without-NonKeyAttributes rejection; the GSI side already had it. An LSI declared with ProjectionType INCLUDE and no NonKeyAttributes is rejected as a ValidationException in tier1 and pinned to the exact message in tier3, the same wording the GSI case returns.

The second pins the Query message for Select SPECIFIC_ATTRIBUTES with no ProjectionExpression, which Scan already had. Query and Scan enforce the same rule but word it differently: Query wraps the phrase in the "1 validation error detected:" envelope, Scan returns it bare.

The transaction cases settle what a conditional TransactWriteItems actually costs. A passing condition adds no read capacity: a conditional write bills the same 2 WCU per sub-1KB item as an unconditional one, and a standalone ConditionCheck costs 2 WCU, billed as write not read. Idempotent replay splits the accounting - the first call reports 2 write capacity units, a same-token replay within the window reports 2 read capacity units for re-reading the stored result. A failing condition cancels the transaction, and the response carries no ConsumedCapacity at all. Answers #27.

 		89.0% -0.4pp fell 0.4 percentage points
89.4% 0.0pp unchanged
89.4% -0.7pp fell 0.7 percentage points

Suite on

Grew to 762 tests, up 18, covering a malformed value in the lookup Key of a TransactWriteItems Update, Delete, or ConditionCheck - the path a Put item key does not take. Captured across four regions (eu-west-2, us-east-1, ap-southeast-2, eu-central-1), where every string was identical, so they pin exactly. An empty-string Key surfaces as a top-level ValidationException with the same message a Put item key gives; a wrong-typed or non-scalar Key cancels with a ValidationError reason carrying "The provided key element does not match the schema" - the key-only form, not the "Type mismatch for key" message the item-key path returns. The same run confirmed the BatchWriteItem table-key schema-mismatch message is region-invariant.

 		90.0% 0.0pp unchanged

Suite on

Grew to 744 tests, up 8, pinning the Select / ProjectionExpression rules on Query and Scan. A ProjectionExpression is only valid with Select SPECIFIC_ATTRIBUTES, and ALL_PROJECTED_ATTRIBUTES is only valid with an IndexName; real DynamoDB rejects both with a ValidationException before reading anything. The cases span ALL_ATTRIBUTES, COUNT, and ALL_PROJECTED_ATTRIBUTES, including the request that breaks both rules at once, where AWS reports the ProjectionExpression one. They assert the contractual phrase, so they hold whether or not the engine carries the wrapper AWS adds on Query but not Scan.

 		90.1% -1.0pp fell 1.0 percentage points

Suite on

Grew to 736 tests, up 30, covering what TransactWriteItems and BatchWriteItem do with an item whose key value is malformed - the wrong type, non-scalar, or an empty string - across both table and index keys. PutItem already covered this; the transactional and batch paths covered none of it.

Characterising it against real AWS turned up a split worth pinning. An empty-string key value is rejected by up-front input validation, so even inside a transaction it surfaces as a top-level ValidationException. A wrong-typed or non-scalar key value is caught while the transaction runs, so it comes back as a TransactionCanceledException carrying a ValidationError reason rather than a top-level error. BatchWriteItem has no cancellation path, so every variant there is a plain ValidationException. The tests pin both halves, which catches two opposite mistakes: an engine that wraps the empty-string case as a cancellation, and one that surfaces the type-mismatch case as a top-level error.

 		91.0% -5.6pp fell 5.6 percentage points

Suite on

Grew to 706 tests, up 7, tightening secondary-index behaviour in Tier 1. Query and Scan on a GSI or LSI now assert sparse membership: an item that omits the index key stays off the index but remains on the base table. And PutItem now rejects an item whose GSI or LSI key value is the wrong type, non-scalar, or an empty string while the base-table keys are valid, holding an index key to its declared scalar type the same way a table key is held.

 		96.6% -0.8pp fell 0.8 percentage points
97.4% 0.0pp unchanged
97.4% 0.0pp unchanged
97.4% 0.0pp unchanged

Suite on

Real DynamoDB in eu-west-2 reworded a chunk of its validation errors, and the Tier 3 error-message tests moved with it. They now assert the contract the error carries - its type, the field it objects to, and the constraint - rather than the exact prose, because AWS varies the wrapper, the echoed input value and the field casing from one region to the next. A four-region capture in June found eu-west-2 and eu-central-1 on the new wording and us-east-1 and ap-southeast-2 still on the old, so the line between contract and cosmetic is drawn from what is invariant across all four.

This moves some Tier 3 numbers. Targets that were only ever marked down for wording DynamoDB itself renders inconsistently now pass those checks, so their Tier 3 scores rise: the suite has stopped counting a cosmetic difference as a behavioural one. Genuine behavioural divergences are still pinned exactly, for example PutItem with a { NULL: false } attribute, which DynamoDB now accepts in eu-west-2 and normalises to { NULL: true }.

 		97.4% +10.4pp rose 10.4 percentage points
87.0% +21.8pp rose 21.8 percentage points

Suite on

Grew to 684 tests with a control-plane and table-configuration sweep: the CreateTable/UpdateTable config parameters and the secondary control-plane operations (limits, backups and PITR, exports and imports, Kinesis, resource policies, contributor insights), each characterised against real AWS and probe-skipped where a target doesn't implement it.

The published percentage changed with it. It now measures correctness over implemented operations, Pass / (Pass + Fail), so skips no longer count against the score. A skip is honest scope; a fail is a bug.

 		65.1% -0.4pp fell 0.4 percentage points
65.5% -0.6pp fell 0.6 percentage points

Suite on

Grew to 625 tests, up 24 on the previous run: eleven more in Tier 1 and thirteen more in Tier 3, tightening coverage of core operations and the strict edge cases.

 		66.1% -2.3pp fell 2.3 percentage points

Suite on

ExtendDB joined the run as a target. The suite itself held steady at 601 tests.

 		68.4% +6.0pp rose 6.0 percentage points

Suite on

Grew to 601 tests, up 29, and every new test landed in Tier 3: a broader strict surface spanning validation ordering, exact error messages, service limits, and the legacy request shapes. Floci and Ministack were added to the run as targets the same day.

 		62.4% first run