diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 00000000..b8728fc8
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,12 @@
+# Faster linking for local dev rebuilds.
+# Uses lld instead of the default bfd linker; requires `lld` from the flake
+# devShell. Run `direnv reload` after changing flake.nix.
+[target.x86_64-unknown-linux-gnu]
+rustflags = ["-C", "link-arg=-fuse-ld=lld"]
+
+# Build first and run the resulting binary outside Cargo. This lets client,
+# server, and test builds share the target cache without a long-lived
+# `cargo run` process holding up another Cargo invocation.
+[alias]
+watch-client = ["watch", "--delay", "0.1", "--ignore", "**/common/src/proto/**", "--exec", "build --package client", "--shell", "workspace_manifest=$(cargo locate-project --workspace --message-format plain); exec ${workspace_manifest%Cargo.toml}target/debug/client client"]
+watch-server = ["watch", "--why", "--delay", "0.1", "--ignore", "**/common/src/proto/**", "--exec", "build --package server", "--shell", "workspace_manifest=$(cargo locate-project --workspace --message-format plain); exec ${workspace_manifest%Cargo.toml}target/debug/server server"]
diff --git a/.gitignore b/.gitignore
index 51745b07..2ba94e12 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,4 @@ tui-pages-cli/
 tui-canvas-validation-core/
 WEBSITE.md
 mutants*/
+AGENT_TESTING_NOTES.md
diff --git a/Cargo.toml b/Cargo.toml
index 0963c8a0..6808fe25 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -63,3 +63,15 @@ common = { path = "./common" }
 [patch.crates-io]
 tui-pages = { path = "tui-pages" }
 tui-canvas = { path = "tui-canvas" }
+
+# Fast dev loop: keep both workspace crates and dependencies cheap to compile.
+# Backtraces still contain symbol names, but omit source line information.
+[profile.dev]
+opt-level = 0
+debug = 0
+incremental = true
+overflow-checks = true
+
+[profile.dev.package."*"]
+opt-level = 0
+debug = false
diff --git a/README.md b/README.md
index 1941fde6..70549ae5 100644
--- a/README.md
+++ b/README.md
@@ -20,8 +20,18 @@ libraries.
 Server and client:
 
 ```
-cargo watch --why -x 'run --package server -- server'
-cargo watch -x 'run --package client -- client'
+cargo watch-server
+cargo watch-client
+```
+
+These aliases only watch each application's local dependency tree. They build
+through Cargo, then run the binary separately so concurrent tests can reuse the
+same build cache.
+
+To connect a client to a second server instance, override its gRPC endpoint:
+
+```
+GRPC_ENDPOINT='http://[::1]:50052' cargo watch-client
 ```
 
 Client with tracing:
diff --git a/client b/client
index f8bc80a4..75221c3a 160000
--- a/client
+++ b/client
@@ -1 +1 @@
-Subproject commit f8bc80a415138e4eb5cb9b70523a9556250d21d4
+Subproject commit 75221c3adb22e3c6d8da59f9a93d5797d49bf7df
diff --git a/common/proto/tables_data.proto b/common/proto/tables_data.proto
index ba453903..a27afb5f 100644
--- a/common/proto/tables_data.proto
+++ b/common/proto/tables_data.proto
@@ -165,6 +165,9 @@ message PostTableDataResponse {
 
   // Revision committed for the inserted row.
   int64 row_revision = 4;
+
+  // Journal created or updated by automatic accounting, when applicable.
+  optional int64 journal_id = 5;
 }
 
 // One row in a bulk insert request.
@@ -251,6 +254,9 @@ message PutTableDataResponse {
 
   // Revision committed for the updated row.
   int64 row_revision = 4;
+
+  // Journal updated by automatic accounting, when applicable.
+  optional int64 journal_id = 5;
 }
 
 message TableUpdateImpactRequest {
diff --git a/common/src/proto/descriptor.bin b/common/src/proto/descriptor.bin
index aaf51e5f..d840f0b6 100644
Binary files a/common/src/proto/descriptor.bin and b/common/src/proto/descriptor.bin differ
diff --git a/common/src/proto/komp_ac.tables_data.rs b/common/src/proto/komp_ac.tables_data.rs
index 4475787c..7a924291 100644
--- a/common/src/proto/komp_ac.tables_data.rs
+++ b/common/src/proto/komp_ac.tables_data.rs
@@ -72,6 +72,9 @@ pub struct PostTableDataResponse {
     /// Revision committed for the inserted row.
     #[prost(int64, tag = "4")]
     pub row_revision: i64,
+    /// Journal created or updated by automatic accounting, when applicable.
+    #[prost(int64, optional, tag = "5")]
+    pub journal_id: ::core::option::Option<i64>,
 }
 /// One row in a bulk insert request.
 #[derive(Clone, PartialEq, ::prost::Message)]
@@ -181,6 +184,9 @@ pub struct PutTableDataResponse {
     /// Revision committed for the updated row.
     #[prost(int64, tag = "4")]
     pub row_revision: i64,
+    /// Journal updated by automatic accounting, when applicable.
+    #[prost(int64, optional, tag = "5")]
+    pub journal_id: ::core::option::Option<i64>,
 }
 #[derive(Clone, PartialEq, Eq, Hash, ::prost::Message)]
 pub struct TableUpdateImpactRequest {
diff --git a/flake.nix b/flake.nix
index 9642b839..5c0adb5d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -13,6 +13,8 @@
       in
       {
         devShells.default = pkgs.mkShell {
+          LD_LIBRARY_PATH = pkgs.lib.makeLibraryPath [ pkgs.openssl ];
+
           buildInputs = with pkgs; [
             mermaid-cli
             # Rust toolchain
@@ -34,6 +36,8 @@
             # C build tools (for your linker issue)
             gcc
             binutils
+            # Fast linker (lld) for quicker dev rebuilds
+            lld
             pkg-config
             
             # OpenSSL for crypto dependencies
diff --git a/server b/server
index f83ebc80..f57088e5 160000
--- a/server
+++ b/server
@@ -1 +1 @@
-Subproject commit f83ebc802a1847a42bf2b193b7e2f31e8d5c5a74
+Subproject commit f57088e548dd3afb14f018697a12e82b13863b42