diff --git a/Cargo.lock b/Cargo.lock
index b27764f..5d72894 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,6 +23,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "arbitrary"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d5a26814d8dcb93b0e5a0ff3c6d80a8843bafb21b39e8e18a6f05471870e110"
+dependencies = [
+ "derive_arbitrary",
+]
+
 [[package]]
 name = "ark-bls12-381"
 version = "0.4.0"
@@ -287,6 +296,16 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "ctor"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a2785755761f3ddc1492979ce1e48d2c00d09311c39e4466429188f3dd6501"
+dependencies = [
+ "quote",
+ "syn 2.0.117",
+]
+
 [[package]]
 name = "curve25519-dalek"
 version = "4.1.3"
@@ -420,6 +439,17 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "derive_arbitrary"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67e77553c4162a157adbf834ebae5b415acbecbeafc7a74b0e886657506a7611"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.117",
+]
+
 [[package]]
 name = "digest"
 version = "0.10.7"
@@ -1145,6 +1175,7 @@ version = "22.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "027cd856171bfd6ad2c0ffb3b7dfe55ad7080fb3050c36ad20970f80da634472"
 dependencies = [
+ "arbitrary",
  "crate-git-revision",
  "ethnum",
  "num-derive",
@@ -1238,7 +1269,11 @@ version = "22.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ff18e8d7ca6d5340a211605ca2c86383bd4dfacc4f8253d72a1573974ffffe69"
 dependencies = [
+ "arbitrary",
  "bytes-lit",
+ "ctor",
+ "derive_arbitrary",
+ "ed25519-dalek",
  "rand",
  "rustc_version",
  "serde",
@@ -1350,6 +1385,7 @@ version = "22.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2ce69db907e64d1e70a3dce8d4824655d154749426a6132b25395c49136013e4"
 dependencies = [
+ "arbitrary",
  "base64 0.13.1",
  "crate-git-revision",
  "escape-bytes",
diff --git a/creator-keys/Cargo.toml b/creator-keys/Cargo.toml
index c54f824..83e8675 100644
--- a/creator-keys/Cargo.toml
+++ b/creator-keys/Cargo.toml
@@ -5,8 +5,11 @@ edition = "2021"
 publish = false
 
 [lib]
-crate-type = ["cdylib"]
+crate-type = ["cdylib", "rlib"]
 
 [dependencies]
 soroban-sdk = { workspace = true }
 
+[dev-dependencies]
+soroban-sdk = { workspace = true, features = ["testutils"] }
+
diff --git a/creator-keys/src/lib.rs b/creator-keys/src/lib.rs
index ee78f53..faf502d 100644
--- a/creator-keys/src/lib.rs
+++ b/creator-keys/src/lib.rs
@@ -2,10 +2,38 @@
 
 use soroban_sdk::{contract, contractimpl, contracttype, symbol_short, Address, Env, String};
 
+pub mod fee {
+    use soroban_sdk::contracttype;
+
+    /// Basis points per 100% (10000 = 100%).
+    pub const BPS_MAX: u32 = 10_000;
+
+    #[derive(Clone)]
+    #[contracttype]
+    pub struct FeeConfig {
+        pub creator_bps: u32,
+        pub protocol_bps: u32,
+    }
+
+    /// Computes the fee split for a given total amount.
+    ///
+    /// Returns `(creator_amount, protocol_amount)`. Remainder from integer division
+    /// is assigned to the creator. Ensures creator_amount + protocol_amount == total.
+    pub fn compute_fee_split(total: i128, _creator_bps: u32, protocol_bps: u32) -> (i128, i128) {
+        if total <= 0 {
+            return (0, 0);
+        }
+        let protocol_amount = (total * protocol_bps as i128) / BPS_MAX as i128;
+        let creator_amount = total - protocol_amount;
+        (creator_amount, protocol_amount)
+    }
+}
+
 #[derive(Clone)]
 #[contracttype]
 pub enum DataKey {
     Creator(Address),
+    FeeConfig,
 }
 
 #[derive(Clone)]
@@ -57,4 +85,91 @@ impl CreatorKeysContract {
         let key = DataKey::Creator(creator);
         env.storage().persistent().get(&key)
     }
+
+    pub fn set_fee_config(env: Env, admin: Address, creator_bps: u32, protocol_bps: u32) {
+        admin.require_auth();
+        if creator_bps + protocol_bps != fee::BPS_MAX {
+            panic!("creator_bps + protocol_bps must equal 10000");
+        }
+        let config = fee::FeeConfig {
+            creator_bps,
+            protocol_bps,
+        };
+        env.storage().persistent().set(&DataKey::FeeConfig, &config);
+    }
+
+    pub fn get_fee_config(env: Env) -> Option<fee::FeeConfig> {
+        env.storage().persistent().get(&DataKey::FeeConfig)
+    }
+
+    pub fn compute_fees_for_payment(env: Env, total: i128) -> (i128, i128) {
+        let config: fee::FeeConfig = env
+            .storage()
+            .persistent()
+            .get(&DataKey::FeeConfig)
+            .unwrap_or_else(|| panic!("fee config not set"));
+        fee::compute_fee_split(total, config.creator_bps, config.protocol_bps)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::fee;
+
+    #[test]
+    fn test_fee_split_90_10_1000() {
+        let (creator, protocol) = fee::compute_fee_split(1000, 9000, 1000);
+        assert_eq!(creator, 900);
+        assert_eq!(protocol, 100);
+        assert_eq!(creator + protocol, 1000);
+    }
+
+    #[test]
+    fn test_fee_split_100_creator() {
+        let (creator, protocol) = fee::compute_fee_split(1000, 10000, 0);
+        assert_eq!(creator, 1000);
+        assert_eq!(protocol, 0);
+        assert_eq!(creator + protocol, 1000);
+    }
+
+    #[test]
+    fn test_fee_split_100_protocol() {
+        let (creator, protocol) = fee::compute_fee_split(1000, 0, 10000);
+        assert_eq!(creator, 0);
+        assert_eq!(protocol, 1000);
+        assert_eq!(creator + protocol, 1000);
+    }
+
+    #[test]
+    fn test_fee_split_remainder_to_creator() {
+        // 999 * 1000 / 10000 = 99 (protocol floor), creator gets remainder
+        let (creator, protocol) = fee::compute_fee_split(999, 9000, 1000);
+        assert_eq!(creator, 900);
+        assert_eq!(protocol, 99);
+        assert_eq!(creator + protocol, 999);
+    }
+
+    #[test]
+    fn test_fee_split_zero_total() {
+        let (creator, protocol) = fee::compute_fee_split(0, 9000, 1000);
+        assert_eq!(creator, 0);
+        assert_eq!(protocol, 0);
+    }
+
+    #[test]
+    fn test_fee_split_dust_total_one() {
+        // 1 * 1000 / 10000 = 0 protocol, creator gets full amount
+        let (creator, protocol) = fee::compute_fee_split(1, 9000, 1000);
+        assert_eq!(creator, 1);
+        assert_eq!(protocol, 0);
+        assert_eq!(creator + protocol, 1);
+    }
+
+    #[test]
+    fn test_fee_split_balance_conservation() {
+        for total in [100_i128, 1, 999, 10000, 1234567] {
+            let (creator, protocol) = fee::compute_fee_split(total, 9000, 1000);
+            assert_eq!(creator + protocol, total, "total={}", total);
+        }
+    }
 }
diff --git a/creator-keys/test_snapshots/test_compute_fees_for_payment.1.json b/creator-keys/test_snapshots/test_compute_fees_for_payment.1.json
new file mode 100644
index 0000000..49aad91
--- /dev/null
+++ b/creator-keys/test_snapshots/test_compute_fees_for_payment.1.json
@@ -0,0 +1,190 @@
+{
+  "generators": {
+    "address": 2,
+    "nonce": 0
+  },
+  "auth": [
+    [],
+    [
+      [
+        "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4",
+        {
+          "function": {
+            "contract_fn": {
+              "contract_address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+              "function_name": "set_fee_config",
+              "args": [
+                {
+                  "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4"
+                },
+                {
+                  "u32": 9000
+                },
+                {
+                  "u32": 1000
+                }
+              ]
+            }
+          },
+          "sub_invocations": []
+        }
+      ]
+    ],
+    []
+  ],
+  "ledger": {
+    "protocol_version": 22,
+    "sequence_number": 0,
+    "timestamp": 0,
+    "network_id": "0000000000000000000000000000000000000000000000000000000000000000",
+    "base_reserve": 0,
+    "min_persistent_entry_ttl": 4096,
+    "min_temp_entry_ttl": 16,
+    "max_entry_ttl": 6312000,
+    "ledger_entries": [
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": {
+              "vec": [
+                {
+                  "symbol": "FeeConfig"
+                }
+              ]
+            },
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": {
+                  "vec": [
+                    {
+                      "symbol": "FeeConfig"
+                    }
+                  ]
+                },
+                "durability": "persistent",
+                "val": {
+                  "map": [
+                    {
+                      "key": {
+                        "symbol": "creator_bps"
+                      },
+                      "val": {
+                        "u32": 9000
+                      }
+                    },
+                    {
+                      "key": {
+                        "symbol": "protocol_bps"
+                      },
+                      "val": {
+                        "u32": 1000
+                      }
+                    }
+                  ]
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": "ledger_key_contract_instance",
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": "ledger_key_contract_instance",
+                "durability": "persistent",
+                "val": {
+                  "contract_instance": {
+                    "executable": {
+                      "wasm": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+                    },
+                    "storage": null
+                  }
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4",
+            "key": {
+              "ledger_key_nonce": {
+                "nonce": 801925984706572462
+              }
+            },
+            "durability": "temporary"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4",
+                "key": {
+                  "ledger_key_nonce": {
+                    "nonce": 801925984706572462
+                  }
+                },
+                "durability": "temporary",
+                "val": "void"
+              }
+            },
+            "ext": "v0"
+          },
+          6311999
+        ]
+      ],
+      [
+        {
+          "contract_code": {
+            "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_code": {
+                "ext": "v0",
+                "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                "code": ""
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ]
+    ]
+  },
+  "events": []
+}
\ No newline at end of file
diff --git a/creator-keys/test_snapshots/test_compute_fees_without_config_panics.1.json b/creator-keys/test_snapshots/test_compute_fees_without_config_panics.1.json
new file mode 100644
index 0000000..a90f00a
--- /dev/null
+++ b/creator-keys/test_snapshots/test_compute_fees_without_config_panics.1.json
@@ -0,0 +1,76 @@
+{
+  "generators": {
+    "address": 1,
+    "nonce": 0
+  },
+  "auth": [
+    [],
+    []
+  ],
+  "ledger": {
+    "protocol_version": 22,
+    "sequence_number": 0,
+    "timestamp": 0,
+    "network_id": "0000000000000000000000000000000000000000000000000000000000000000",
+    "base_reserve": 0,
+    "min_persistent_entry_ttl": 4096,
+    "min_temp_entry_ttl": 16,
+    "max_entry_ttl": 6312000,
+    "ledger_entries": [
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": "ledger_key_contract_instance",
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": "ledger_key_contract_instance",
+                "durability": "persistent",
+                "val": {
+                  "contract_instance": {
+                    "executable": {
+                      "wasm": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+                    },
+                    "storage": null
+                  }
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_code": {
+            "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_code": {
+                "ext": "v0",
+                "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                "code": ""
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ]
+    ]
+  },
+  "events": []
+}
\ No newline at end of file
diff --git a/creator-keys/test_snapshots/test_set_and_get_fee_config.1.json b/creator-keys/test_snapshots/test_set_and_get_fee_config.1.json
new file mode 100644
index 0000000..49aad91
--- /dev/null
+++ b/creator-keys/test_snapshots/test_set_and_get_fee_config.1.json
@@ -0,0 +1,190 @@
+{
+  "generators": {
+    "address": 2,
+    "nonce": 0
+  },
+  "auth": [
+    [],
+    [
+      [
+        "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4",
+        {
+          "function": {
+            "contract_fn": {
+              "contract_address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+              "function_name": "set_fee_config",
+              "args": [
+                {
+                  "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4"
+                },
+                {
+                  "u32": 9000
+                },
+                {
+                  "u32": 1000
+                }
+              ]
+            }
+          },
+          "sub_invocations": []
+        }
+      ]
+    ],
+    []
+  ],
+  "ledger": {
+    "protocol_version": 22,
+    "sequence_number": 0,
+    "timestamp": 0,
+    "network_id": "0000000000000000000000000000000000000000000000000000000000000000",
+    "base_reserve": 0,
+    "min_persistent_entry_ttl": 4096,
+    "min_temp_entry_ttl": 16,
+    "max_entry_ttl": 6312000,
+    "ledger_entries": [
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": {
+              "vec": [
+                {
+                  "symbol": "FeeConfig"
+                }
+              ]
+            },
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": {
+                  "vec": [
+                    {
+                      "symbol": "FeeConfig"
+                    }
+                  ]
+                },
+                "durability": "persistent",
+                "val": {
+                  "map": [
+                    {
+                      "key": {
+                        "symbol": "creator_bps"
+                      },
+                      "val": {
+                        "u32": 9000
+                      }
+                    },
+                    {
+                      "key": {
+                        "symbol": "protocol_bps"
+                      },
+                      "val": {
+                        "u32": 1000
+                      }
+                    }
+                  ]
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": "ledger_key_contract_instance",
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": "ledger_key_contract_instance",
+                "durability": "persistent",
+                "val": {
+                  "contract_instance": {
+                    "executable": {
+                      "wasm": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+                    },
+                    "storage": null
+                  }
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4",
+            "key": {
+              "ledger_key_nonce": {
+                "nonce": 801925984706572462
+              }
+            },
+            "durability": "temporary"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4",
+                "key": {
+                  "ledger_key_nonce": {
+                    "nonce": 801925984706572462
+                  }
+                },
+                "durability": "temporary",
+                "val": "void"
+              }
+            },
+            "ext": "v0"
+          },
+          6311999
+        ]
+      ],
+      [
+        {
+          "contract_code": {
+            "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_code": {
+                "ext": "v0",
+                "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                "code": ""
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ]
+    ]
+  },
+  "events": []
+}
\ No newline at end of file
diff --git a/creator-keys/test_snapshots/test_set_fee_config_invalid_sum_panics.1.json b/creator-keys/test_snapshots/test_set_fee_config_invalid_sum_panics.1.json
new file mode 100644
index 0000000..5655749
--- /dev/null
+++ b/creator-keys/test_snapshots/test_set_fee_config_invalid_sum_panics.1.json
@@ -0,0 +1,76 @@
+{
+  "generators": {
+    "address": 2,
+    "nonce": 0
+  },
+  "auth": [
+    [],
+    []
+  ],
+  "ledger": {
+    "protocol_version": 22,
+    "sequence_number": 0,
+    "timestamp": 0,
+    "network_id": "0000000000000000000000000000000000000000000000000000000000000000",
+    "base_reserve": 0,
+    "min_persistent_entry_ttl": 4096,
+    "min_temp_entry_ttl": 16,
+    "max_entry_ttl": 6312000,
+    "ledger_entries": [
+      [
+        {
+          "contract_data": {
+            "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+            "key": "ledger_key_contract_instance",
+            "durability": "persistent"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_data": {
+                "ext": "v0",
+                "contract": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD2KM",
+                "key": "ledger_key_contract_instance",
+                "durability": "persistent",
+                "val": {
+                  "contract_instance": {
+                    "executable": {
+                      "wasm": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+                    },
+                    "storage": null
+                  }
+                }
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ],
+      [
+        {
+          "contract_code": {
+            "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+          }
+        },
+        [
+          {
+            "last_modified_ledger_seq": 0,
+            "data": {
+              "contract_code": {
+                "ext": "v0",
+                "hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+                "code": ""
+              }
+            },
+            "ext": "v0"
+          },
+          4095
+        ]
+      ]
+    ]
+  },
+  "events": []
+}
\ No newline at end of file
diff --git a/creator-keys/tests/fee_split.rs b/creator-keys/tests/fee_split.rs
new file mode 100644
index 0000000..03d45c9
--- /dev/null
+++ b/creator-keys/tests/fee_split.rs
@@ -0,0 +1,61 @@
+//! Deterministic tests for fee split logic and contract integration.
+
+use creator_keys::{CreatorKeysContract, CreatorKeysContractClient};
+use soroban_sdk::{testutils::Address as _, Env};
+
+#[test]
+fn test_set_and_get_fee_config() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(CreatorKeysContract, ());
+    let client = CreatorKeysContractClient::new(&env, &contract_id);
+
+    let admin = soroban_sdk::Address::generate(&env);
+    client.set_fee_config(&admin, &9000u32, &1000u32);
+
+    let config = client.get_fee_config();
+    let config = config.unwrap();
+    assert_eq!(config.creator_bps, 9000);
+    assert_eq!(config.protocol_bps, 1000);
+}
+
+#[test]
+fn test_compute_fees_for_payment() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(CreatorKeysContract, ());
+    let client = CreatorKeysContractClient::new(&env, &contract_id);
+    let admin = soroban_sdk::Address::generate(&env);
+
+    client.set_fee_config(&admin, &9000u32, &1000u32);
+
+    let (creator, protocol) = client.compute_fees_for_payment(&1000i128);
+    assert_eq!(creator, 900);
+    assert_eq!(protocol, 100);
+    assert_eq!(creator + protocol, 1000);
+}
+
+#[test]
+#[should_panic(expected = "creator_bps + protocol_bps must equal 10000")]
+fn test_set_fee_config_invalid_sum_panics() {
+    let env = Env::default();
+    env.mock_all_auths();
+
+    let contract_id = env.register(CreatorKeysContract, ());
+    let client = CreatorKeysContractClient::new(&env, &contract_id);
+    let admin = soroban_sdk::Address::generate(&env);
+
+    client.set_fee_config(&admin, &8000u32, &1000u32);
+}
+
+#[test]
+#[should_panic(expected = "fee config not set")]
+fn test_compute_fees_without_config_panics() {
+    let env = Env::default();
+    let contract_id = env.register(CreatorKeysContract, ());
+    let client = CreatorKeysContractClient::new(&env, &contract_id);
+
+    client.compute_fees_for_payment(&1000i128);
+}
diff --git a/docs/fee-assumptions.md b/docs/fee-assumptions.md
new file mode 100644
index 0000000..1a3c083
--- /dev/null
+++ b/docs/fee-assumptions.md
@@ -0,0 +1,72 @@
+# Fee Split Assumptions
+
+This document describes the assumptions, behavior, and integration points for creator and protocol fee split logic in Access Layer contracts.
+
+## Fee Representation
+
+- **Basis points (bps)**: Fee shares are expressed in basis points, where 10,000 = 100%.
+- **Validation**: `creator_bps + protocol_bps` must equal 10,000. Any other sum is rejected.
+- **Example**: 9,000 creator_bps + 1,000 protocol_bps = 90% creator, 10% protocol.
+
+## Rounding and Remainder Handling
+
+- **Protocol amount**: Computed as `floor(total * protocol_bps / 10000)`.
+- **Creator amount**: `total - protocol_amount`, so the remainder from integer division goes to the creator.
+- **Balance conservation**: `creator_amount + protocol_amount == total` for all valid inputs.
+- **Zero and negative**: For `total <= 0`, returns `(0, 0)`.
+
+### Examples
+
+| total | creator_bps | protocol_bps | creator | protocol |
+|-------|-------------|--------------|---------|----------|
+| 1000  | 9000        | 1000         | 900     | 100      |
+| 1000  | 10000       | 0            | 1000    | 0        |
+| 1000  | 0           | 10000        | 0       | 1000     |
+| 999   | 9000        | 1000         | 900     | 99       |
+| 0     | 9000        | 1000         | 0       | 0        |
+| 1     | 9000        | 1000         | 1       | 0        |
+
+## Overflow and Precision Limits
+
+- **Amount type**: `i128` (Soroban token amounts).
+- **Overflow**: `total * protocol_bps` must fit in `i128`. For typical 7-decimal tokens, this is safe for amounts up to approximately 10^20 smallest units.
+- **Dust**: Amounts of 1 or 2 units may round protocol share to 0; creator receives the full amount.
+
+## Storage and Configuration
+
+- **DataKey**: `FeeConfig` stores a global `FeeConfig` struct with `creator_bps` and `protocol_bps`.
+- **Initialization**: Fee config must be set explicitly via `set_fee_config` before `compute_fees_for_payment` can be used.
+- **Admin**: `set_fee_config` requires authorization of the `admin` address. Admin key management is out of scope for this module.
+
+## Contract Interface
+
+| Function | Purpose |
+|----------|---------|
+| `set_fee_config(env, admin, creator_bps, protocol_bps)` | Set fee split; requires admin auth. |
+| `get_fee_config(env)` | Read current fee config. |
+| `compute_fees_for_payment(env, total)` | Compute `(creator_amount, protocol_amount)` from stored config. |
+
+## Integration with Payment Flow
+
+The fee split logic is designed to be called from the payment handler (see `contracts-economics-02`):
+
+1. Receive total payment amount (e.g., from bonding-curve buy).
+2. Call `compute_fees_for_payment(env, total)` to get `(creator_amount, protocol_amount)`.
+3. Transfer `creator_amount` to the creator.
+4. Transfer `protocol_amount` to the protocol treasury.
+
+Token transfers are not implemented in this module.
+
+## Client and Server Implications
+
+### Events
+
+When buy/sell flows emit events, include `(creator_amount, protocol_amount)` in the payload so indexers and UIs can display the fee breakdown without recomputing. The payment handler (future work) should emit these values.
+
+### Quote Flow
+
+Clients can call `get_fee_config` and `compute_fees_for_payment` (or a view that wraps them) to show users a fee preview before they sign a transaction.
+
+### Indexing
+
+Server/indexer can rely on fee breakdown in events for analytics and display. No additional off-chain computation is required for fee display.