diff --git a/crates/plasm-runtime/src/execution/compile_preflight.rs b/crates/plasm-runtime/src/execution/compile_preflight.rs
index 41f4eb9f..c8c82dcb 100644
--- a/crates/plasm-runtime/src/execution/compile_preflight.rs
+++ b/crates/plasm-runtime/src/execution/compile_preflight.rs
@@ -138,7 +138,7 @@ fn preflight_compile_create(
             message: e.to_string(),
         }
     })?;
-    apply_preflight_compile_stubs(&mut env, capability);
+    apply_preflight_compile_stubs(&mut env, capability, cgs);
     merge_plasm_execute_session_env(&mut env);
     compile_operation_dispatch(&capability_template, &env).map(|_| ())
 }
@@ -237,7 +237,7 @@ fn preflight_compile_invoke(invoke: &InvokeExpr, cgs: &CGS) -> Result<(), Runtim
         }
     })?;
     merge_entity_id_from_into_input_env(&mut env, target_ent, capability);
-    apply_preflight_compile_stubs(&mut env, capability);
+    apply_preflight_compile_stubs(&mut env, capability, cgs);
     merge_plasm_execute_session_env(&mut env);
     compile_operation_dispatch(&capability_template, &env).map(|_| ())
 }
diff --git a/crates/plasm-runtime/src/preflight.rs b/crates/plasm-runtime/src/preflight.rs
index 5a48cc72..df825e63 100644
--- a/crates/plasm-runtime/src/preflight.rs
+++ b/crates/plasm-runtime/src/preflight.rs
@@ -121,7 +121,11 @@ pub(crate) async fn apply_preflight_steps(
 }
 
 /// Compile-only preflight: inject stub merge keys so CML templates compile without HTTP hydration.
-pub(crate) fn apply_preflight_compile_stubs(env: &mut CmlEnv, capability: &CapabilitySchema) {
+pub(crate) fn apply_preflight_compile_stubs(
+    env: &mut CmlEnv,
+    capability: &CapabilitySchema,
+    cgs: &CGS,
+) {
     let Some(PreflightPlan(steps)) = capability.preflight.as_ref() else {
         return;
     };
@@ -133,7 +137,10 @@ pub(crate) fn apply_preflight_compile_stubs(env: &mut CmlEnv, capability: &Capab
                 }
                 for wire_key in merge.keys() {
                     if env.get(wire_key).is_none() {
-                        env.insert(wire_key.clone(), preflight_compile_stub_value(wire_key));
+                        env.insert(
+                            wire_key.clone(),
+                            preflight_wire_key_compile_stub_value(wire_key),
+                        );
                     }
                 }
             }
@@ -145,7 +152,10 @@ pub(crate) fn apply_preflight_compile_stubs(env: &mut CmlEnv, capability: &Capab
                 }
                 for wire_key in merge.keys() {
                     if env.get(wire_key).is_none() {
-                        env.insert(wire_key.clone(), preflight_compile_stub_value(wire_key));
+                        env.insert(
+                            wire_key.clone(),
+                            preflight_wire_key_compile_stub_value(wire_key),
+                        );
                     }
                 }
             }
@@ -161,13 +171,24 @@ pub(crate) fn apply_preflight_compile_stubs(env: &mut CmlEnv, capability: &Capab
                     env.insert(merge.clone(), Value::Array(Vec::new()));
                 }
             }
-            PreflightStep::HydrateInvokeTarget { .. } => {}
+            PreflightStep::HydrateInvokeTarget { get, prefix } => {
+                let Some(get_cap) = cgs.get_capability(get) else {
+                    continue;
+                };
+                let Some(entity) = cgs.get_entity(get_cap.domain.as_str()) else {
+                    continue;
+                };
+                for field_name in entity.fields.keys() {
+                    let key = format!("{prefix}_{field_name}");
+                    env.insert(key.clone(), preflight_wire_key_compile_stub_value(&key));
+                }
+            }
             PreflightStep::ExistenceCheck { .. } => {}
         }
     }
 }
 
-fn preflight_compile_stub_value(wire_key: &str) -> Value {
+fn preflight_wire_key_compile_stub_value(wire_key: &str) -> Value {
     if wire_key.ends_with("Id")
         || wire_key.ends_with("_id")
         || wire_key == "id"
diff --git a/crates/plasm-runtime/tests/hydrate_invoke_target.rs b/crates/plasm-runtime/tests/hydrate_invoke_target.rs
new file mode 100644
index 00000000..ce12bad0
--- /dev/null
+++ b/crates/plasm-runtime/tests/hydrate_invoke_target.rs
@@ -0,0 +1,45 @@
+use plasm_core::{Expr, InvokeExpr, Value, CGS};
+use plasm_runtime::{preflight_compile_expr, ViewAmbientContext};
+
+fn fixture() -> CGS {
+    let dir = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("../../fixtures/schemas/hydrate_invoke_target");
+    plasm_core::load_schema(&dir).expect("load hydrate_invoke_target fixture")
+}
+
+fn run_expr(capability: &str) -> Expr {
+    let mut input = indexmap::indexmap! {
+        "expr".to_string() => Value::String("up".to_string()),
+    };
+    if capability == "datasource_run" {
+        input.insert(
+            "from".to_string(),
+            Value::String("2026-08-03T03:50:00Z".to_string()),
+        );
+        input.insert(
+            "to".to_string(),
+            Value::String("2026-08-03T04:00:00Z".to_string()),
+        );
+    }
+    Expr::Invoke(InvokeExpr::new(
+        capability,
+        "Datasource",
+        "prometheus",
+        Some(Value::Object(input)),
+    ))
+}
+
+#[test]
+fn static_compile_hydrates_declared_entity_fields_and_honors_prefix() {
+    let cgs = fixture();
+    let ambient = ViewAmbientContext::default();
+
+    preflight_compile_expr(&run_expr("datasource_run"), &cgs, &ambient)
+        .expect("ds_type comes from Datasource fields even though provides omits it");
+    preflight_compile_expr(&run_expr("datasource_run_source_prefix"), &cgs, &ambient)
+        .expect("source_type should honor the configured prefix");
+
+    let error = preflight_compile_expr(&run_expr("datasource_run_typo"), &cgs, &ambient)
+        .expect_err("ds_typo must remain an unknown CML variable");
+    assert!(error.to_string().contains("ds_typo"), "{error}");
+}
diff --git a/fixtures/schemas/hydrate_invoke_target/domain.yaml b/fixtures/schemas/hydrate_invoke_target/domain.yaml
new file mode 100644
index 00000000..c514f7fe
--- /dev/null
+++ b/fixtures/schemas/hydrate_invoke_target/domain.yaml
@@ -0,0 +1,95 @@
+version: 1
+http_backend: http://localhost:1080
+
+values:
+  nv_datasource_uid:
+    type: string
+    string_semantics: short
+  nv_datasource_type:
+    type: string
+    string_semantics: short
+  nv_query_expr:
+    type: string
+    string_semantics: short
+  nv_query_time:
+    type: string
+    string_semantics: short
+  nv_query_results:
+    type: json
+
+entities:
+  Datasource:
+    id_field: uid
+    description: Datasource used to test invoke-target preflight hydration.
+    fields:
+      uid:
+        required: true
+        value_ref: nv_datasource_uid
+      type:
+        required: true
+        value_ref: nv_datasource_type
+      query_results:
+        required: false
+        value_ref: nv_query_results
+
+capabilities:
+  datasource_get:
+    kind: get
+    entity: Datasource
+    provides:
+      - uid
+      # `type` is deliberately omitted: provides must not restrict decoded-row hydration.
+
+  datasource_run:
+    kind: action
+    entity: Datasource
+    preflight:
+      - kind: hydrate_invoke_target
+        get: datasource_get
+        prefix: ds
+    parameters:
+      - name: expr
+        value_ref: nv_query_expr
+        required: true
+      - name: from
+        value_ref: nv_query_time
+        required: true
+      - name: to
+        value_ref: nv_query_time
+        required: true
+    provides:
+      - uid
+      - query_results
+
+  datasource_run_typo:
+    kind: action
+    entity: Datasource
+    preflight:
+      - kind: hydrate_invoke_target
+        get: datasource_get
+        prefix: ds
+    parameters:
+      - name: expr
+        value_ref: nv_query_expr
+        required: true
+    provides:
+      - uid
+      - query_results
+
+  datasource_run_source_prefix:
+    kind: action
+    entity: Datasource
+    preflight:
+      - kind: hydrate_invoke_target
+        get: datasource_get
+        prefix: source
+    parameters:
+      - name: expr
+        value_ref: nv_query_expr
+        required: true
+    provides:
+      - uid
+      - query_results
+
+auth:
+  scheme: none
diff --git a/fixtures/schemas/hydrate_invoke_target/mappings.yaml b/fixtures/schemas/hydrate_invoke_target/mappings.yaml
new file mode 100644
index 00000000..79778d1a
--- /dev/null
+++ b/fixtures/schemas/hydrate_invoke_target/mappings.yaml
@@ -0,0 +1,60 @@
+datasource_get:
+  method: GET
+  path:
+    - { type: literal, value: api }
+    - { type: literal, value: datasources }
+    - { type: literal, value: uid }
+    - { type: var, name: id }
+  response:
+    single: true
+
+datasource_run:
+  method: POST
+  path:
+    - { type: literal, value: api }
+    - { type: literal, value: ds }
+    - { type: literal, value: query }
+  body:
+    type: object
+    fields:
+      - [queries, { type: array, elements: [
+          { type: object, fields: [
+            [datasource, { type: object, fields: [
+              [type, { type: var, name: ds_type }],
+              [uid, { type: var, name: id }]
+            ]}],
+            [expr, { type: var, name: expr }]
+          ]}
+        ]}]
+      - [from, { type: var, name: from }]
+      - [to, { type: var, name: to }]
+  response:
+    single: true
+
+datasource_run_typo:
+  method: POST
+  path:
+    - { type: literal, value: api }
+    - { type: literal, value: ds }
+    - { type: literal, value: query }
+  body:
+    type: object
+    fields:
+      - [datasourceType, { type: var, name: ds_typo }]
+      - [expr, { type: var, name: expr }]
+  response:
+    single: true
+
+datasource_run_source_prefix:
+  method: POST
+  path:
+    - { type: literal, value: api }
+    - { type: literal, value: ds }
+    - { type: literal, value: query }
+  body:
+    type: object
+    fields:
+      - [datasourceType, { type: var, name: source_type }]
+      - [expr, { type: var, name: expr }]
+  response:
+    single: true