diff --git a/justfile b/justfile
index 0ba88a6e7..9dd690ee7 100644
--- a/justfile
+++ b/justfile
@@ -64,8 +64,12 @@ sync-schema:
 # Install dependencies and build workspace packages.
 [unix]
 _setup-dev-deps:
-    pnpm install
-    cd sdk && pnpm build
+    ./scripts/ensure-dev-deps.sh --force
+
+# Repair only stale development dependencies and workspace package outputs.
+[unix]
+_ensure-dev-deps:
+    ./scripts/ensure-dev-deps.sh
 
 [unix]
 _install-lefthook:
@@ -469,10 +473,11 @@ dev:
     #!/usr/bin/env bash
     set -euo pipefail
 
-    if [[ -n "${GOOSE_BIN:-}" ]]; then
-        just _setup-no-goose
-    else
-        GOOSE_BUILD_PROFILE=debug just setup
+    just _ensure-dev-deps
+
+    if [[ -z "${GOOSE_BIN:-}" ]]; then
+        LOCAL_GOOSE_BIN="$(GOOSE_DEV_MODE=required GOOSE_BUILD_PROFILE=debug ./scripts/ensure-local-goose.sh --print-bin)"
+        export GOOSE_BIN="$LOCAL_GOOSE_BIN"
     fi
 
     VITE_PORT="$(python3 -c "import hashlib,os; h=int(hashlib.sha256(os.getcwd().encode()).hexdigest(),16); print(10000 + h % 55000)")"
@@ -507,20 +512,7 @@ dev:
         ./scripts/prepare-bb-cli-resource.sh
     fi
 
-    if [[ -n "${GOOSE_BIN:-}" ]]; then
-        echo "Using explicitly set GOOSE_BIN: ${GOOSE_BIN}"
-    else
-        LOCAL_GOOSE_BIN="$(GOOSE_BUILD_PROFILE=debug ./scripts/ensure-local-goose.sh --check-bin)" || {
-            rc=$?
-            if [[ $rc -eq 2 ]]; then
-                echo "❌ Local goose binary is not ready. Run 'just setup' first." >&2
-                exit 1
-            fi
-            exit $rc
-        }
-        export GOOSE_BIN="$LOCAL_GOOSE_BIN"
-        echo "Using local goose binary: ${GOOSE_BIN}"
-    fi
+    echo "Using Goose binary: ${GOOSE_BIN}"
 
     DISTRO_DIR="$(pwd)/distro"
     if [[ -z "${GOOSE_DISTRO_DIR:-}" && -d "$DISTRO_DIR" ]]; then
diff --git a/scripts/ensure-dev-deps.sh b/scripts/ensure-dev-deps.sh
new file mode 100755
index 000000000..ee9364cdb
--- /dev/null
+++ b/scripts/ensure-dev-deps.sh
@@ -0,0 +1,103 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+repo_root="$(cd "$script_dir/.." && pwd)"
+force=0
+
+if [[ "${1:-}" == "--force" ]]; then
+  force=1
+  shift
+fi
+
+if [[ $# -ne 0 ]]; then
+  echo "Usage: scripts/ensure-dev-deps.sh [--force]" >&2
+  exit 2
+fi
+
+pnpm_bin="${PNPM_BIN:-pnpm}"
+dependency_stamp="$repo_root/node_modules/.berd-dev-dependency-inputs.sha256"
+installed_lock="$repo_root/node_modules/.pnpm/lock.yaml"
+sdk_stamp="$repo_root/sdk/dist/.berd-dev-build-inputs.sha256"
+
+hash_files() {
+  local path
+  for path in "$@"; do
+    if [[ -d "$path" ]]; then
+      find "$path" -type f -print
+    elif [[ -f "$path" ]]; then
+      printf '%s\n' "$path"
+    fi
+  done \
+    | LC_ALL=C sort -u \
+    | while IFS= read -r path; do
+        shasum -a 256 "$path"
+      done \
+    | shasum -a 256 \
+    | awk '{print $1}'
+}
+
+stamp_matches() {
+  local stamp="$1"
+  local expected="$2"
+  [[ -f "$stamp" ]] && [[ "$(<"$stamp")" == "$expected" ]]
+}
+
+write_stamp() {
+  local stamp="$1"
+  local value="$2"
+  local temp_stamp
+  mkdir -p "$(dirname "$stamp")"
+  temp_stamp="$(mktemp "${stamp}.XXXXXX")"
+  printf '%s\n' "$value" >"$temp_stamp"
+  mv "$temp_stamp" "$stamp"
+}
+
+dependency_inputs_hash() {
+  hash_files \
+    "$repo_root/package.json" \
+    "$repo_root/pnpm-lock.yaml" \
+    "$repo_root/pnpm-workspace.yaml" \
+    "$repo_root/sdk/package.json"
+}
+
+sdk_inputs_hash() {
+  hash_files \
+    "$repo_root/pnpm-lock.yaml" \
+    "$repo_root/pnpm-workspace.yaml" \
+    "$repo_root/sdk/package.json" \
+    "$repo_root/sdk/tsconfig.json" \
+    "$repo_root/sdk/generate-schema.ts" \
+    "$repo_root/sdk/schema" \
+    "$repo_root/sdk/src"
+}
+
+dependency_inputs="$(dependency_inputs_hash)"
+
+if [[ "$force" == "1" ]] \
+  || ! stamp_matches "$dependency_stamp" "$dependency_inputs" \
+  || [[ ! -f "$installed_lock" ]] \
+  || ! cmp -s "$repo_root/pnpm-lock.yaml" "$installed_lock"; then
+  echo "Preparing pnpm dependencies."
+  (cd "$repo_root" && "$pnpm_bin" install)
+  dependency_inputs="$(dependency_inputs_hash)"
+  write_stamp "$dependency_stamp" "$dependency_inputs"
+else
+  echo "pnpm dependencies are current; skipping install."
+fi
+
+sdk_inputs="$(sdk_inputs_hash)"
+
+if [[ "$force" == "1" ]] \
+  || ! stamp_matches "$sdk_stamp" "$sdk_inputs" \
+  || [[ ! -f "$repo_root/sdk/dist/index.js" ]] \
+  || [[ ! -f "$repo_root/sdk/dist/index.d.ts" ]]; then
+  echo "Building @aaif/goose-sdk."
+  (cd "$repo_root/sdk" && "$pnpm_bin" build)
+  # Schema generation is part of the SDK build and may update derived source
+  # files, so record the inputs after the successful build.
+  sdk_inputs="$(sdk_inputs_hash)"
+  write_stamp "$sdk_stamp" "$sdk_inputs"
+else
+  echo "@aaif/goose-sdk is current; skipping build."
+fi
diff --git a/scripts/release/tests/release-scripts.test.mjs b/scripts/release/tests/release-scripts.test.mjs
index 2f1253c76..ca9eb225d 100644
--- a/scripts/release/tests/release-scripts.test.mjs
+++ b/scripts/release/tests/release-scripts.test.mjs
@@ -118,7 +118,7 @@ describe("managed Goose build profile", () => {
       /_bundle-debug-unix:[\s\S]*if \[\[ -z "\$\{GOOSE_BIN:-\}" \]\]; then[\s\S]*GOOSE_BUILD_PROFILE=debug \.\/scripts\/ensure-local-goose\.sh/,
     );
     expect(justfile).toMatch(
-      /dev:[\s\S]*GOOSE_BUILD_PROFILE=debug just setup[\s\S]*GOOSE_BUILD_PROFILE=debug \.\/scripts\/ensure-local-goose\.sh --check-bin/,
+      /dev:[\s\S]*just _ensure-dev-deps[\s\S]*GOOSE_DEV_MODE=required GOOSE_BUILD_PROFILE=debug \.\/scripts\/ensure-local-goose\.sh --print-bin/,
     );
     expect(devE2e).toContain("GOOSE_BUILD_PROFILE=debug just setup");
     expect(schema).toContain("GOOSE_BUILD_PROFILE=debug");
diff --git a/scripts/release/tests/setup-tooling.test.mjs b/scripts/release/tests/setup-tooling.test.mjs
index a1292fc92..de6ab3d12 100644
--- a/scripts/release/tests/setup-tooling.test.mjs
+++ b/scripts/release/tests/setup-tooling.test.mjs
@@ -76,6 +76,65 @@ async function callsFor(path) {
   return readFile(path, "utf8").catch(() => "");
 }
 
+async function devDepsFixture() {
+  const root = await mkdtemp(join(tmpdir(), "berd-dev-deps-"));
+  tempDirs.push(root);
+  const scriptDir = join(root, "scripts");
+  const sdkDir = join(root, "sdk");
+  const fakePnpm = join(root, "fake-pnpm");
+  const calls = join(root, "pnpm-calls");
+
+  await Promise.all([
+    mkdir(scriptDir),
+    mkdir(join(sdkDir, "schema"), { recursive: true }),
+    mkdir(join(sdkDir, "src"), { recursive: true }),
+  ]);
+  await Promise.all([
+    copyFile(
+      join(repo, "scripts/ensure-dev-deps.sh"),
+      join(scriptDir, "ensure-dev-deps.sh"),
+    ),
+    writeFile(join(root, "package.json"), '{"name":"fixture"}\n'),
+    writeFile(join(root, "pnpm-lock.yaml"), "lockfileVersion: '9.0'\n"),
+    writeFile(join(root, "pnpm-workspace.yaml"), "packages: ['.', 'sdk']\n"),
+    writeFile(join(sdkDir, "package.json"), '{"name":"sdk"}\n'),
+    writeFile(join(sdkDir, "tsconfig.json"), "{}\n"),
+    writeFile(join(sdkDir, "generate-schema.ts"), "export {};\n"),
+    writeFile(join(sdkDir, "schema/schema.json"), "{}\n"),
+    writeFile(join(sdkDir, "src/index.ts"), "export {};\n"),
+    writeFile(
+      fakePnpm,
+      `#!/bin/bash
+set -euo pipefail
+printf '%s:%s\\n' "$PWD" "$*" >> "${calls}"
+if [[ "\${1:-}" == "install" ]]; then
+  if [[ "\${PNPM_REWRITE_LOCK:-0}" == "1" ]] && ! grep -q autoInstallPeers pnpm-lock.yaml; then
+    printf 'settings:\n  autoInstallPeers: true\n' >> pnpm-lock.yaml
+  fi
+  mkdir -p node_modules/.pnpm
+  cp pnpm-lock.yaml node_modules/.pnpm/lock.yaml
+elif [[ "\${1:-}" == "build" ]]; then
+  mkdir -p dist
+  touch dist/index.js dist/index.d.ts
+fi
+`,
+    ),
+  ]);
+  await Promise.all([
+    chmod(join(scriptDir, "ensure-dev-deps.sh"), 0o755),
+    chmod(fakePnpm, 0o755),
+  ]);
+
+  const run = (args = [], env = {}) =>
+    spawnSync(join(scriptDir, "ensure-dev-deps.sh"), args, {
+      cwd: root,
+      encoding: "utf8",
+      env: { ...process.env, PNPM_BIN: fakePnpm, ...env },
+    });
+
+  return { root, calls, run };
+}
+
 afterEach(async () => {
   await Promise.all(
     tempDirs
@@ -85,21 +144,92 @@ afterEach(async () => {
 });
 
 describe("setup tooling regressions", () => {
-  it("uses the SDK's direct build commands through the pnpm setup recipe", async () => {
-    const [sdkPackage, justfile] = await Promise.all([
+  it("routes full setup and incremental dev preparation through the dependency guard", async () => {
+    const [sdkPackage, justfile, ensureDevDeps] = await Promise.all([
       readFile(join(repo, "sdk/package.json"), "utf8"),
       readFile(justfilePath, "utf8"),
+      readFile(join(repo, "scripts/ensure-dev-deps.sh"), "utf8"),
     ]);
 
     expect(JSON.parse(sdkPackage).scripts.build).toBe(
       "tsx generate-schema.ts && tsc",
     );
     expect(justfile).toMatch(
-      /_setup-dev-deps:\n {4}pnpm install\n {4}cd sdk && pnpm build\n/,
+      /_setup-dev-deps:\n {4}\.\/scripts\/ensure-dev-deps\.sh --force\n/,
+    );
+    expect(justfile).toMatch(
+      /_ensure-dev-deps:\n {4}\.\/scripts\/ensure-dev-deps\.sh\n/,
     );
     expect(justfile).toMatch(
       /_install-lefthook:\n {4}\.\/scripts\/install-lefthook\.sh\n/,
     );
+    expect(ensureDevDeps).toContain('"$pnpm_bin" install');
+    expect(ensureDevDeps).toContain('"$pnpm_bin" build');
+  });
+
+  it("records dependency inputs after pnpm updates the lockfile", async () => {
+    const fixture = await devDepsFixture();
+
+    const initial = fixture.run([], { PNPM_REWRITE_LOCK: "1" });
+    expect(initial.status, `${initial.stdout}\n${initial.stderr}`).toBe(0);
+
+    await writeFile(fixture.calls, "");
+    const warm = fixture.run();
+    expect(warm.status, `${warm.stdout}\n${warm.stderr}`).toBe(0);
+    expect(warm.stdout).toContain("skipping install");
+    expect(warm.stdout).toContain("skipping build");
+    expect(await callsFor(fixture.calls)).toBe("");
+  });
+
+  it("skips current dependencies and rebuilds only stale SDK inputs", async () => {
+    const fixture = await devDepsFixture();
+
+    const first = fixture.run();
+    expect(first.status, `${first.stdout}\n${first.stderr}`).toBe(0);
+    expect(await callsFor(fixture.calls)).toBe(
+      `${fixture.root}:install\n${join(fixture.root, "sdk")}:build\n`,
+    );
+
+    await writeFile(fixture.calls, "");
+    const warm = fixture.run();
+    expect(warm.status, `${warm.stdout}\n${warm.stderr}`).toBe(0);
+    expect(warm.stdout).toContain("skipping install");
+    expect(warm.stdout).toContain("skipping build");
+    expect(await callsFor(fixture.calls)).toBe("");
+
+    await writeFile(fixture.calls, "");
+    await writeFile(
+      join(fixture.root, "pnpm-lock.yaml"),
+      "lockfileVersion: '9.0'\nsettings:\n  autoInstallPeers: true\n",
+    );
+    const dependencyChange = fixture.run();
+    expect(
+      dependencyChange.status,
+      `${dependencyChange.stdout}\n${dependencyChange.stderr}`,
+    ).toBe(0);
+    expect(await callsFor(fixture.calls)).toBe(
+      `${fixture.root}:install\n${join(fixture.root, "sdk")}:build\n`,
+    );
+
+    await writeFile(fixture.calls, "");
+    await writeFile(
+      join(fixture.root, "sdk/src/index.ts"),
+      "export const changed = true;\n",
+    );
+    const sdkChange = fixture.run();
+    expect(sdkChange.status, `${sdkChange.stdout}\n${sdkChange.stderr}`).toBe(
+      0,
+    );
+    expect(await callsFor(fixture.calls)).toBe(
+      `${join(fixture.root, "sdk")}:build\n`,
+    );
+
+    await writeFile(fixture.calls, "");
+    const forced = fixture.run(["--force"]);
+    expect(forced.status, `${forced.stdout}\n${forced.stderr}`).toBe(0);
+    expect(await callsFor(fixture.calls)).toBe(
+      `${fixture.root}:install\n${join(fixture.root, "sdk")}:build\n`,
+    );
   });
 
   it("prefers the repository-local lefthook shim over PATH", async () => {