Create an optional hook system for externally-managed verification

.claude/commands/formspec.check.8.md

@@ -83,9 +83,13 @@ Perform each of these checks and record findings:
 - If System.tla is newer than verification/matrix.md, flag that verification may be stale
 - If design docs are newer than documentation files, flag potential documentation drift
 
-### 3. Run TLC (if spec exists)
+### 3. Run verification
 
-If `spec/formal/System.tla` and `spec/formal/System.cfg` exist:
+If `spec/hooks/run-checks` exists and is executable, delegate all verification (TLC and language-specific tools) to it (see `/formspec.init` for the hook interface). Build the request from `spec/formal/traceability.md` (TLA+ properties), `spec/plan.md` (verification methods), and detected source files (language-specific checks). The external system runs all checks independently and returns results.
+
+If the hook does not exist or fails, run checks locally:
+
+**TLC** (if `spec/formal/System.tla` and `spec/formal/System.cfg` exist):
 
 ```bash
 tlc spec/formal/System.tla -config spec/formal/System.cfg -workers auto -metadir /tmp/tlc-states -cleanup
@@ -93,7 +97,7 @@ tlc spec/formal/System.tla -config spec/formal/System.cfg -workers auto -metadir
 
 Record pass/fail for each property.
 
-### 4. Run language-specific verification tools (if implementation exists)
+**Language-specific verification tools** (if implementation exists):
 
 Detect the project's language(s) from source files and run appropriate tools:
 - **Rust**: `cargo test`, `cargo clippy`
@@ -104,7 +108,7 @@ Detect the project's language(s) from source files and run appropriate tools:
 
 Only run tools that are available and applicable. Skip gracefully if tooling isn't set up.
 
-### 5. Report
+### 4. Report
 
 Produce a structured report organized by severity: