diff --git a/docs/profile-schema.md b/docs/profile-schema.md
index d39021e..1797fbe 100644
--- a/docs/profile-schema.md
+++ b/docs/profile-schema.md
@@ -51,6 +51,47 @@ take the next-higher number; deleted files retire their number.
 | `regression`   | list   | `[]`           | Regression scripts run by the audit skill. Each entry is a shell command; non-zero exit is a regress. |
 | `architect_sweeps` | list | `[]`         | Project-specific architect sweep commands run by the `architect` agent in addition to its universal checks. Each entry is a shell command; non-zero exit means at least one sweep matched and the matches are drift-suspicions to verify. Optional. |
 
+## `spec_validation`
+
+Optional. A registry mapping each markdown fence label to the tool
+that validates a spec code block of that kind. The brainstorm
+parse-gate and the grounding-check code-block pass run these
+parsers so that spec code blocks are treated as hypotheses to
+verify, not as authoritative truth.
+
+```yaml
+spec_validation:
+  parsers:
+    ail:
+      ext: ".ail"
+      cmd: "ail parse {file}"
+    ail-json:
+      ext: ".ail.json"
+      cmd: "ail check {file}"
+    ll:
+      ext: ".ll"
+      cmd: "llvm-as {file} -o /dev/null"
+```
+
+The key of each `parsers` entry is the fence info-string of a spec
+code block (the token immediately after the opening ` ``` `). Only
+blocks whose label has an entry are validated; a block whose label
+is absent from the map is skipped and the skip is documented ("no
+parser for fence label X") — never a silent pass.
+
+| Key   | Type   | Description |
+|-------|--------|-------------|
+| `ext` | string | Extension (including the leading dot) the harness gives the temp file it writes the block into, so tools that key off extension — `.ail` vs `.ail.json` — see the right one. |
+| `cmd` | string | Validation command. MUST contain the `{file}` placeholder, which is substituted with the temp file's path. Exit 0 means a clean parse; any non-zero exit is a parse failure the consuming skill turns into a BLOCK. |
+
+A malformed entry — `cmd` missing the `{file}` placeholder, or
+either `ext` or `cmd` absent — is a profile error the consuming
+skill surfaces, not a silent skip; the gate fails closed.
+
+Omitting the whole `spec_validation` section disables the
+block-validation gates: the consuming skills short-circuit, exactly
+as with other omitted optional features.
+
 ## `vocabulary`
 
 | Key            | Type   | Default        | Description |
diff --git a/templates/project-profile.yml b/templates/project-profile.yml
index 98cb385..736f52f 100644
--- a/templates/project-profile.yml
+++ b/templates/project-profile.yml
@@ -28,6 +28,15 @@ commands:
   regression: []                          # list of shell commands run by audit; non-zero exit = regress
   architect_sweeps: []                    # optional project-specific architect sweeps; non-zero exit = drift suspicion
 
+# spec_validation:                        # optional — fence label -> validator for spec code blocks
+#   parsers:                              # key = fence info-string; labels with no entry are skipped + documented
+#     ail:
+#       ext: ".ail"                       # extension for the temp file the harness writes the block into
+#       cmd: "ail parse {file}"           # {file} = temp-file path; exit 0 = clean parse, non-zero = BLOCK
+#     ail-json:
+#       ext: ".ail.json"
+#       cmd: "ail check {file}"
+
 vocabulary:
   cycle: cycle                            # what a top-level work unit is called
   subcycle: iteration                     # what a sub-unit is called