diff --git a/lib/core/src/Cardano/Wallet.hs b/lib/core/src/Cardano/Wallet.hs
index d62bbf083b5..6c3aef01ede 100644
--- a/lib/core/src/Cardano/Wallet.hs
+++ b/lib/core/src/Cardano/Wallet.hs
@@ -2261,7 +2261,6 @@ data ErrStartTimeLaterThanEndTime = ErrStartTimeLaterThanEndTime
 data ErrSelectForDelegation
     = ErrSelectForDelegationNoSuchWallet ErrNoSuchWallet
     | ErrSelectForDelegationFee ErrAdjustForFee
-    | ErrSelectForDelegationUnableToAssignInputs ErrNoSuchWallet
     deriving (Show, Eq)
 
 -- | Errors that can occur when signing a delegation certificate.
diff --git a/lib/core/src/Cardano/Wallet/Api/Server.hs b/lib/core/src/Cardano/Wallet/Api/Server.hs
index 01e4634affa..46e294e154f 100644
--- a/lib/core/src/Cardano/Wallet/Api/Server.hs
+++ b/lib/core/src/Cardano/Wallet/Api/Server.hs
@@ -2540,7 +2540,6 @@ instance LiftHandler ErrSelectForDelegation where
                 [ "I'm unable to select enough coins to pay for a "
                 , "delegation certificate. I need: ", showT cost, " Lovelace."
                 ]
-        ErrSelectForDelegationUnableToAssignInputs e -> handler e
 
 instance LiftHandler ErrSignDelegation where
     handler = \case
diff --git a/specifications/api/swagger.yaml b/specifications/api/swagger.yaml
index 4d446dfcfb6..ad1efa991bb 100644
--- a/specifications/api/swagger.yaml
+++ b/specifications/api/swagger.yaml
@@ -1840,12 +1840,337 @@ x-responsesErr: &responsesErr
       description: A specific error code for this error, more precise than HTTP ones.
       example: an_error_code
 
+x-responsesErrWalletNotFound: &responsesErrWalletNotFound
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['no_such_wallet']
+
+x-responsesErrBadRequest: &responsesErrBadRequest
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: Explanation of a good request.
+    code:
+      type: string
+      enum: ['bad_request']
+
+x-responsesErrNotJson: &responsesErrNotJson
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive message explaining the expected media type is JSON.
+    code:
+      type: string
+      enum: ['unsupported_media_type']
+
+x-responsesErrNotAcceptable: &responsesErrNotAcceptable
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive message explaining acceptable headers.
+    code:
+      type: string
+      enum: ['not_acceptable']
+
+x-responsesErrWalletAlreadyExists: &responsesErrWalletAlreadyExists
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: Explanation of wallet with conflicting id.
+    code:
+      type: string
+      enum: ['wallet_already_exists']
+
+x-errWithRootKeyNoRootKey: &errWithRootKeyNoRootKey
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['no_root_key']
+
+x-errWithRootKeyWrongPassphrase: &errWithRootKeyWrongPassphrase
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['wrong_encryption_passphrase']
+
+x-errInvalidWalletType: &errInvalidWalletType
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: Explanation of a valid wallet type.
+    code:
+      type: string
+      enum: ['invalid_wallet_type']
+
+x-errAlreadyWithdrawing: &errAlreadyWithdrawing
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['already_withdrawing']
+
+x-errTransactionIsTooBig: &errTransactionIsTooBig
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['transaction_is_too_big']
+
+x-errUTxOTooSmall: &errUTxOTooSmall
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['utxo_too_small']
+
+x-errCannotCoverFee: &errCannotCoverFee
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['cannot_cover_fee']
+
+x-errNotEnoughMoney: &errNotEnoughMoney
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['not_enough_money']
+
+x-errInputsDepleted: &errInputsDepleted
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['inputs_depleted']
+
+x-errInvalidSelection: &errInvalidSelection
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['invalid_coin_selection']
+
+x-errWithRootKey: &errWithRootKey
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['no_root_key']
+
+x-errMinWithdrawalWrong: &errMinWithdrawalWrong
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['min_withdrawal_wrong']
+
+x-errStartTimeLaterThanEndTime: &errStartTimeLaterThanEndTime
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['start_time_later_than_end_time']
+
+x-errTransactionNotPending: &errTransactionNotPending
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['transaction_not_pending']
+
+x-errNoSuchTransaction: &errNoSuchTransaction
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A message describing the transaction ID that could not be found.
+    code:
+      type: string
+      enum: ['no_such_transaction']
+
+x-errQueryParamMissing: &errQueryParamMissing
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['query_param_missing']
+
+x-errNotDelegating: &errNotDelegating
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['not_delegating_to']
+
+x-errNonNullRewards: &errNonNullRewards
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['non_null_rewards']
+
+x-errAlreadyDelegating: &errAlreadyDelegating
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['pool_already_joined']
+
+x-errNoSuchPool: &errNoSuchPool
+  type: object
+  required:
+    - message
+    - code
+  properties:
+    message:
+      type: string
+      description: A descriptive error message.
+    code:
+      type: string
+      enum: ['no_such_pool']
+
 x-responsesErr400: &responsesErr400
   400:
     description: Bad Request
     content:
       application/json:
-        schema: *responsesErr
+        schema: *responsesErrBadRequest
 
 x-responsesErr403: &responsesErr403
   403:
@@ -1873,7 +2198,7 @@ x-responsesErr406: &responsesErr406
     description: Not Acceptable
     content:
       application/json:
-        schema: *responsesErr
+        schema: *responsesErrNotAcceptable
 
 x-responsesErr409: &responsesErr409
   409:
@@ -1903,8 +2228,28 @@ x-responsesErr423: &responsesErr423
       application/json:
         schema: *responsesErr
 
+x-responsesErr404WalletNotFound: &responsesErr404WalletNotFound
+  404:
+    description: Not Found
+    content:
+      application/json:
+        schema: *responsesErrWalletNotFound
+
+x-responsesErr409WalletAlreadyExists: &responsesErr409WalletAlreadyExists
+  409:
+    description: Conflict
+    content:
+      application/json:
+        schema: *responsesErrWalletAlreadyExists
+
+x-responsesErr415NotJson: &responsesErr415NotJson
+  415:
+    description: Unsupported Media Type
+    content:
+      application/json:
+        schema: *responsesErrNotJson
+
 x-responsesListWallets: &responsesListWallets
-  <<: *responsesErr405
   <<: *responsesErr406
   200:
     description: Ok
@@ -1926,8 +2271,7 @@ x-responsesListByronWallets: &responsesListByronWallets
           items: *ApiByronWallet
 
 x-responsesGetUTxOsStatistics: &responsesGetUTxOsStatistics
-  <<: *responsesErr404
-  <<: *responsesErr405
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
   200:
     description: Ok
@@ -1937,10 +2281,9 @@ x-responsesGetUTxOsStatistics: &responsesGetUTxOsStatistics
 
 x-responsesPostWallet: &responsesPostWallet
   <<: *responsesErr400
-  <<: *responsesErr405
   <<: *responsesErr406
-  <<: *responsesErr409
-  <<: *responsesErr415
+  <<: *responsesErr409WalletAlreadyExists
+  <<: *responsesErr415NotJson
   201:
     description: Created
     content:
@@ -1960,8 +2303,8 @@ x-responsesPostByronWallet: &responsesPostByronWallet
         schema: *ApiByronWallet
 
 x-responsesGetWallet: &responsesGetWallet
-  <<: *responsesErr404
-  <<: *responsesErr405
+  <<: *responsesErr400
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
   200:
     description: Ok
@@ -2004,8 +2347,8 @@ x-responsesMigrateWallet: &responsesMigrateWallet
           items: *ApiTransaction
 
 x-responsesDeleteWallet: &responsesDeleteWallet
-  <<: *responsesErr404
-  <<: *responsesErr405
+  <<: *responsesErr400
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
   204:
     description: No Content
@@ -2022,10 +2365,9 @@ x-responsesForceResyncWallet: &responsesForceResyncWallet
 
 x-responsesPutWallet: &responsesPutWallet
   <<: *responsesErr400
-  <<: *responsesErr404
-  <<: *responsesErr405
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
-  <<: *responsesErr415
+  <<: *responsesErr415NotJson
   200:
     description: Ok
     content:
@@ -2034,11 +2376,17 @@ x-responsesPutWallet: &responsesPutWallet
 
 x-responsesPutWalletPassphrase: &responsesPutWalletPassphrase
   <<: *responsesErr400
-  <<: *responsesErr403
-  <<: *responsesErr404
-  <<: *responsesErr405
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *errWithRootKeyNoRootKey
+            - <<: *errWithRootKeyWrongPassphrase
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
-  <<: *responsesErr415
+  <<: *responsesErr415NotJson
   204:
     description: No Content
 
@@ -2056,16 +2404,33 @@ x-responsesSelectCoins: &responsesSelectCoins
         schema: *ApiCoinSelection
 
 x-responsesDeleteTransaction: &responsesDeleteTransaction
-  <<: *responsesErr403
-  <<: *responsesErr404
-  <<: *responsesErr405
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema: *errTransactionNotPending
+  404:
+    description: Not Found
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *responsesErrWalletNotFound
+            - <<: *errNoSuchTransaction
   <<: *responsesErr406
   204:
     description: No Content
 
 x-responsesListTransactions: &responsesListTransactions
-  <<: *responsesErr404
-  <<: *responsesErr405
+  400:
+    description: Bad Request
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *errMinWithdrawalWrong
+            - <<: *errStartTimeLaterThanEndTime
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
   200:
     description: Ok
@@ -2081,8 +2446,14 @@ x-responsesListTransactions: &responsesListTransactions
           items: *ApiTransaction
 
 x-responsesGetTransaction: &responsesGetTransaction
-  <<: *responsesErr404
-  <<: *responsesErr405
+  404:
+    description: Not Found
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *responsesErrWalletNotFound
+            - <<: *errNoSuchTransaction
   <<: *responsesErr406
   200:
     description: OK
@@ -2091,12 +2462,37 @@ x-responsesGetTransaction: &responsesGetTransaction
         schema: *ApiTransaction
 
 x-responsesPostTransaction: &responsesPostTransaction
-  <<: *responsesErr400
-  <<: *responsesErr403
-  <<: *responsesErr404
-  <<: *responsesErr405
+  400:
+    description: Bad Request
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *responsesErrBadRequest
+            - <<: *errTransactionIsTooBig
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *errInvalidWalletType
+            - <<: *errAlreadyWithdrawing
+            - <<: *errUTxOTooSmall
+            - <<: *errCannotCoverFee
+            - <<: *errNotEnoughMoney
+            - <<: *errTransactionIsTooBig
+            - <<: *errWithRootKey
+            - <<: *errWithRootKeyWrongPassphrase
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
-  <<: *responsesErr415
+  410:
+    description: Gone
+    content:
+      application/json:
+        schema:
+          <<: *responsesErrWalletNotFound
+  <<: *responsesErr415NotJson
   202:
     description: Accepted
     content:
@@ -2115,12 +2511,31 @@ x-responsesPostExternalTransaction: &responsesPostExternalTransaction
         schema: *ApiTxId
 
 x-responsesPostTransactionFee: &responsesPostTransactionFee
-  <<: *responsesErr400
-  <<: *responsesErr403
-  <<: *responsesErr404
-  <<: *responsesErr405
+  400:
+    description: Bad Request
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *responsesErrBadRequest
+            - <<: *errTransactionIsTooBig
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *errInvalidWalletType
+            - <<: *errAlreadyWithdrawing
+            - <<: *errUTxOTooSmall
+            - <<: *errCannotCoverFee
+            - <<: *errNotEnoughMoney
+            - <<: *errInputsDepleted
+            - <<: *errInvalidSelection
+            - <<: *errTransactionIsTooBig
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
-  <<: *responsesErr415
+  <<: *responsesErr415NotJson
   202:
     description: Accepted
     content:
@@ -2128,9 +2543,12 @@ x-responsesPostTransactionFee: &responsesPostTransactionFee
         schema: *ApiFee
 
 x-responsesGetDelegationFee: &responsesGetDelegationFee
-  <<: *responsesErr403
-  <<: *responsesErr404
-  <<: *responsesErr405
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema: *errCannotCoverFee
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
   200:
     description: Ok
@@ -2140,8 +2558,7 @@ x-responsesGetDelegationFee: &responsesGetDelegationFee
 
 x-responsesListAddresses: &responsesListAddresses
   <<: *responsesErr400
-  <<: *responsesErr404
-  <<: *responsesErr405
+  <<: *responsesErr404WalletNotFound
   <<: *responsesErr406
   200:
     description: Ok
@@ -2152,8 +2569,11 @@ x-responsesListAddresses: &responsesListAddresses
           items: *ApiAddress
 
 x-responsesListStakePools: &responsesListStakePools
-  <<: *responsesErr405
-  <<: *responsesErr404
+  400:
+    description: Bad Request
+    content:
+      application/json:
+        schema: *errQueryParamMissing
   200:
     description: Ok
     content:
@@ -2169,11 +2589,32 @@ x-responsesListStakePools: &responsesListStakePools
 
 x-responsesJoinStakePool: &responsesJoinStakePool
   <<: *responsesErr400
-  <<: *responsesErr403
-  <<: *responsesErr404
-  <<: *responsesErr405
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *errCannotCoverFee
+            - <<: *errWithRootKey
+            - <<: *errWithRootKeyWrongPassphrase
+            - <<: *errAlreadyDelegating
+  404:
+    description: Not Found
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *responsesErrWalletNotFound
+            - <<: *errNoSuchPool
   <<: *responsesErr406
-  <<: *responsesErr415
+  410:
+    description: Gone
+    content:
+      application/json:
+        schema:
+          <<: *responsesErrWalletNotFound
+  <<: *responsesErr415NotJson
   202:
     description: Accepted
     content:
@@ -2181,7 +2622,32 @@ x-responsesJoinStakePool: &responsesJoinStakePool
         schema: *ApiTransaction
 
 x-responsesQuitStakePool: &responsesQuitStakePool
-  <<: *responsesJoinStakePool
+  <<: *responsesErr400
+  403:
+    description: Forbidden
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - <<: *errCannotCoverFee
+            - <<: *errWithRootKey
+            - <<: *errWithRootKeyWrongPassphrase
+            - <<: *errNotDelegating
+            - <<: *errNonNullRewards
+  <<: *responsesErr404WalletNotFound
+  <<: *responsesErr406
+  410:
+    description: Gone
+    content:
+      application/json:
+        schema:
+          <<: *responsesErrWalletNotFound
+  <<: *responsesErr415NotJson
+  202:
+    description: Accepted
+    content:
+      application/json:
+        schema: *ApiTransaction
 
 x-responsesGetNetworkInformation: &responsesGetNetworkInformation
   <<: *responsesErr405