diff --git a/.github/workflows/e2e-standalone.yml b/.github/workflows/e2e-standalone.yml
index 03bc3fe27..68523860b 100644
--- a/.github/workflows/e2e-standalone.yml
+++ b/.github/workflows/e2e-standalone.yml
@@ -1,8 +1,17 @@
 name: Stakgraph E2E Standalone Test
+# Builds the standalone binary (ast, lsp, shared, standalone) and the mcp node
+# server, so nearly everything is an input. Skip only what it never compiles or
+# reads: gateway (Go), notes, cli (separate workspace), skill, and docs.
 on:
   pull_request:
     branches:
       - main
+    paths-ignore:
+      - "gateway/**"
+      - "notes/**"
+      - "cli/**"
+      - "skill/**"
+      - "**.md"
 
 jobs:
   run-standalone-e2e-test:
diff --git a/.github/workflows/e2e-test.yml b/.github/workflows/e2e-test.yml
index 9d17c0580..925c6f078 100644
--- a/.github/workflows/e2e-test.yml
+++ b/.github/workflows/e2e-test.yml
@@ -1,8 +1,17 @@
 name: Stakgraph E2E Test
+# Builds the `index` binary (ast, lsp, shared) and the mcp node server, so nearly
+# everything is an input. Skip only what it never compiles or reads: gateway (Go),
+# notes, cli (separate workspace), skill, and docs.
 on:
   pull_request:
     branches:
       - main
+    paths-ignore:
+      - "gateway/**"
+      - "notes/**"
+      - "cli/**"
+      - "skill/**"
+      - "**.md"
 
 jobs:
   run-test:
diff --git a/.github/workflows/rust-test-cli.yml b/.github/workflows/rust-test-cli.yml
index dc3e1409e..7d13ee737 100644
--- a/.github/workflows/rust-test-cli.yml
+++ b/.github/workflows/rust-test-cli.yml
@@ -1,8 +1,15 @@
 name: Stakgraph CLI Test
+# cli is its own cargo workspace (own Cargo.lock) that path-depends on ast/lsp/shared.
 on:
   pull_request:
     branches:
       - main
+    paths:
+      - "cli/**"
+      - "ast/**"
+      - "lsp/**"
+      - "shared/**"
+      - ".github/workflows/rust-test-cli.yml"
 
 jobs:
   run-cli-test:
diff --git a/.github/workflows/rust-test-lsp.yml b/.github/workflows/rust-test-lsp.yml
index 4b91313fc..d977620b5 100644
--- a/.github/workflows/rust-test-lsp.yml
+++ b/.github/workflows/rust-test-lsp.yml
@@ -1,8 +1,16 @@
 name: Stakgraph Unit Test (LSP)
+# Same test surface as rust-test.yml (ast --lib), run with USE_LSP=true.
 on:
   pull_request:
     branches:
       - main
+    paths:
+      - "ast/**"
+      - "lsp/**"
+      - "shared/**"
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - ".github/workflows/rust-test-lsp.yml"
 
 jobs:
   run-test-lsp:
diff --git a/.github/workflows/rust-test.yml b/.github/workflows/rust-test.yml
index 4be94c1cc..82e6e1cb3 100644
--- a/.github/workflows/rust-test.yml
+++ b/.github/workflows/rust-test.yml
@@ -1,8 +1,16 @@
 name: Stakgraph Unit Test
+# Only `cargo test -p ast --lib`: ast and the crates it pulls in (lsp, shared).
 on:
   pull_request:
     branches:
       - main
+    paths:
+      - "ast/**"
+      - "lsp/**"
+      - "shared/**"
+      - "Cargo.toml"
+      - "Cargo.lock"
+      - ".github/workflows/rust-test.yml"
 
 jobs:
   run-test:
diff --git a/.github/workflows/standalone-test.yml b/.github/workflows/standalone-test.yml
index 7e0e128ed..d9d7ff774 100644
--- a/.github/workflows/standalone-test.yml
+++ b/.github/workflows/standalone-test.yml
@@ -1,8 +1,17 @@
 name: Stakgraph Standalone Test
+# Runs `cargo test` over the whole root workspace (ast, lsp, shared, skill, standalone)
+# and boots Neo4j from mcp/, so nearly everything is an input. Skip only the
+# directories it provably never touches: gateway (Go), notes, cli (separate
+# workspace, not a member), and docs.
 on:
   pull_request:
     branches:
       - main
+    paths-ignore:
+      - "gateway/**"
+      - "notes/**"
+      - "cli/**"
+      - "**.md"
 
 jobs:
   run-standalone-test: