Value provided in ExpressionAttributeValues unused in expressions

TL;DR — You supplied a value placeholder in ExpressionAttributeValues (e.g. :status) that no expression references. DynamoDB requires every declared :value to be used in a KeyConditionExpression, FilterExpression, UpdateExpression, or ConditionExpression. Remove the orphan value — or fix the expression that was meant to use it.

What it means

ValidationException: Value provided in ExpressionAttributeValues unused in
expressions: keys: {:status}

ExpressionAttributeValues is the substitution map for the literal values your expressions compare against (:status, :min, …). DynamoDB enforces a two-way contract: every :placeholder used in an expression must be declared, and every declared placeholder must be used. A leftover value that no expression references triggers this HTTP 400 ValidationException — client-side and not retryable until the maps match.

Why it happens

• A stale value after editing the expression — you dropped #s = :status from the expression but left :status in the values map.
• Copy-paste drift — reusing a values map from a previous request that had more conditions than the current one.
• A generated request that over-declares — a builder added :v for a filter clause that was later removed.
• A name-vs-value mix-up — you meant #status (a name alias) but declared :status (a value).
• A typo — the expression uses :stat while the map declares :status.

How to fix it

1. Delete the unused value the message names from ExpressionAttributeValues.
2. Keep values in lock-step with the expression — declare a :placeholder only when an expression references it.
3. Confirm names vs values — : placeholders go in ExpressionAttributeValues; # aliases go in ExpressionAttributeNames.
4. Build the expression and its maps together so no value is left dangling.

Related errors

• Value provided in ExpressionAttributeNames unused in expressions — the same rule for #name aliases.
• ExpressionAttributeValues contains invalid value — a malformed or empty value in the map.
• An expression attribute value used in expression is not defined — the reverse: a placeholder referenced but not supplied.