diff --git a/AGENTS.md b/AGENTS.md
index 3681e0a..1a17210 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -25,9 +25,13 @@ for human and operational workflows; content and section mutations are not CLI
 commands.
 
 Every MCP structured result must have an object root, and each advertised output
-schema must be precise and derived from its boundary DTO. Arbitrary JSON schema
-terms must use object form rather than bare boolean terms. Every MCP change must
-pass the repository-wide strict-client output-schema contract test.
+schema must be precise and derived from its boundary DTO's serialized JSON
+contract: fields, requiredness, JSON types, value and structural constraints,
+and references. `format` annotations are intentionally omitted: client support
+is nonportable, so they do not establish a client-facing validation or UI
+contract; server-side validation is authoritative. Arbitrary JSON schema terms
+must use object form rather than bare boolean terms. Every MCP change must pass
+the repository-wide strict-client output-schema contract test.
 
 
 ## Build & Test
diff --git a/flicknote-cli/src/main_tests/mcp.rs b/flicknote-cli/src/main_tests/mcp.rs
index 82c2b48..3d40ac2 100644
--- a/flicknote-cli/src/main_tests/mcp.rs
+++ b/flicknote-cli/src/main_tests/mcp.rs
@@ -474,6 +474,26 @@ fn assert_no_boolean_schema_terms(schema: &serde_json::Value, tool: &str) {
     }
 }
 
+fn assert_no_schema_formats(schema: &serde_json::Value, tool: &str) {
+    match schema {
+        serde_json::Value::Object(map) => {
+            assert!(
+                !map.contains_key("format"),
+                "tool {tool}: schema contains a format annotation: {schema}"
+            );
+            for value in map.values() {
+                assert_no_schema_formats(value, tool);
+            }
+        }
+        serde_json::Value::Array(values) => {
+            for value in values {
+                assert_no_schema_formats(value, tool);
+            }
+        }
+        _ => {}
+    }
+}
+
 #[tokio::test]
 async fn mcp_tool_output_schemas_are_strict_client_compatible() {
     let mut harness = McpHarness::start().await;
@@ -487,6 +507,8 @@ async fn mcp_tool_output_schemas_are_strict_client_compatible() {
             "tool {name}: outputSchema root type must be object"
         );
         assert_no_boolean_schema_terms(output, name);
+        assert_no_schema_formats(output, name);
+        assert_no_schema_formats(&tool["inputSchema"], name);
     }
 
     let list = tools
diff --git a/flicknote-cli/src/mcp/server.rs b/flicknote-cli/src/mcp/server.rs
index 8402058..f63e6d4 100644
--- a/flicknote-cli/src/mcp/server.rs
+++ b/flicknote-cli/src/mcp/server.rs
@@ -75,10 +75,21 @@ impl FlickNoteMcp {
     pub(crate) fn new(config: Arc<Config>) -> Self {
         Self {
             config,
-            tool_router: Self::tool_router(),
+            tool_router: Self::normalized_tool_router(),
         }
     }
 
+    fn normalized_tool_router() -> ToolRouter<Self> {
+        let mut router = Self::tool_router();
+        for route in router.map.values_mut() {
+            normalize_schema_formats(Arc::make_mut(&mut route.attr.input_schema));
+            if let Some(output_schema) = &mut route.attr.output_schema {
+                normalize_schema_formats(Arc::make_mut(output_schema));
+            }
+        }
+        router
+    }
+
     async fn call<T: AppResult>(&self, request: AppRequest) -> Result<T, ServiceError> {
         DaemonClient::new(&self.config).call(request).await
     }
@@ -100,6 +111,33 @@ impl FlickNoteMcp {
     }
 }
 
+/// Remove generator-specific format annotations from advertised MCP schemas.
+///
+/// The server remains the authority for value validation; MCP clients do not
+/// provide a useful user-facing behavior for these annotations.
+fn normalize_schema_formats(schema: &mut serde_json::Map<String, serde_json::Value>) {
+    fn visit(value: &mut serde_json::Value) {
+        match value {
+            serde_json::Value::Object(object) => {
+                object.remove("format");
+                for value in object.values_mut() {
+                    visit(value);
+                }
+            }
+            serde_json::Value::Array(values) => {
+                for value in values {
+                    visit(value);
+                }
+            }
+            _ => {}
+        }
+    }
+
+    for value in schema.values_mut() {
+        visit(value);
+    }
+}
+
 fn structured<T>(result: Result<T, ServiceError>) -> Result<Json<T>, CallToolResult> {
     result.map(Json).map_err(|error| tool_error(&error))
 }