diff --git a/server-rs/Cargo.lock b/server-rs/Cargo.lock
index 12885c91a..c5f022286 100644
--- a/server-rs/Cargo.lock
+++ b/server-rs/Cargo.lock
@@ -4162,6 +4162,7 @@ version = "0.1.0"
 dependencies = [
  "bytes",
  "reqwest",
+ "serde",
  "serde_json",
  "shared-contracts",
  "tokio",
diff --git a/server-rs/crates/api-server/src/tripo3d/job.rs b/server-rs/crates/api-server/src/tripo3d/job.rs
index f26b9a830..0c63406b1 100644
--- a/server-rs/crates/api-server/src/tripo3d/job.rs
+++ b/server-rs/crates/api-server/src/tripo3d/job.rs
@@ -78,11 +78,13 @@ impl Model3dJobRequest {
         }
     }
 
-    pub(crate) fn model_version(&self) -> &'static str {
-        match self {
-            Self::TextToModel(request) => request.generation.model.as_str(),
-            Self::ImageToModel(request) => request.generation.model.as_str(),
-        }
+    /// 审计与落库用的模型版本线上取值；取值只由契约枚举的 serde rename 定义。
+    pub(crate) fn model_version(&self) -> String {
+        let model = match self {
+            Self::TextToModel(request) => request.generation.model,
+            Self::ImageToModel(request) => request.generation.model,
+        };
+        shared_contracts::model3d::wire_str_lossy(&model)
     }
 }
 
diff --git a/server-rs/crates/api-server/src/tripo3d/pricing.rs b/server-rs/crates/api-server/src/tripo3d/pricing.rs
index 6b1989bf2..e40a1aa93 100644
--- a/server-rs/crates/api-server/src/tripo3d/pricing.rs
+++ b/server-rs/crates/api-server/src/tripo3d/pricing.rs
@@ -10,6 +10,7 @@ use serde::{Deserialize, Serialize};
 use shared_contracts::model3d::common::{
     Model3dGeometryQuality, Model3dModelVersion, Model3dTextureQuality,
 };
+use shared_contracts::model3d::wire_str_lossy;
 
 /// 生成端点。批量价键与请求入口一一对应，不做 provider 侧的变形。
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Ord, PartialEq, PartialOrd, Serialize)]
@@ -158,7 +159,7 @@ impl std::fmt::Display for Model3dPricingError {
                 f,
                 "Tripo 3D 定价缺少底价：endpoint={} model={}",
                 endpoint.as_str(),
-                model_version.as_str()
+                wire_str_lossy(model_version)
             ),
             Self::MissingAddOnPrice(add_on) => {
                 write!(f, "Tripo 3D 定价缺少 add-on：{add_on:?}")
@@ -182,7 +183,7 @@ impl Model3dPricingConfig {
                     return Err(format!(
                         "缺少 endpoint {} 模型 {} 的底价",
                         endpoint.as_str(),
-                        model_version.as_str()
+                        wire_str_lossy(&model_version)
                     ));
                 }
             }
@@ -191,7 +192,7 @@ impl Model3dPricingConfig {
                     return Err(format!(
                         "endpoint {} 出现了契约不支持的模型版本 {}",
                         endpoint.as_str(),
-                        model_version.as_str()
+                        wire_str_lossy(model_version)
                     ));
                 }
             }
diff --git a/server-rs/crates/platform-tripo/Cargo.toml b/server-rs/crates/platform-tripo/Cargo.toml
index 4196df708..086a9fec8 100644
--- a/server-rs/crates/platform-tripo/Cargo.toml
+++ b/server-rs/crates/platform-tripo/Cargo.toml
@@ -6,6 +6,7 @@ license.workspace = true
 
 [dependencies]
 shared-contracts = { workspace = true }
+serde = { workspace = true }
 serde_json = { workspace = true }
 tripo3d-sdk = { workspace = true }
 bytes = { workspace = true }
diff --git a/server-rs/crates/platform-tripo/src/common/extra.rs b/server-rs/crates/platform-tripo/src/common/extra.rs
index 14ef2d2cd..569f98007 100644
--- a/server-rs/crates/platform-tripo/src/common/extra.rs
+++ b/server-rs/crates/platform-tripo/src/common/extra.rs
@@ -9,23 +9,23 @@ use std::collections::HashMap;
 use serde_json::Value;
 use shared_contracts::model3d::common::Model3dTextureVersion;
 
+use super::{TripoError, wire};
+
 const EXTRA_TEXTURE_VERSION: &str = "texture_version";
 const EXTRA_DELIGHT: &str = "delight";
 
-/// 按 provider 需要的键名构造 `extra`；未提供的参数不写入，由 provider 取默认值。
+/// 按 provider 需要的键名构造 `extra`；未提供的参数不写入，由 provider 取默认值；
+/// `texture_version` 的取值仍由契约枚举的 serde rename 定义。
 pub(crate) fn extra_fields(
     texture_version: Option<Model3dTextureVersion>,
     delight: Option<bool>,
-) -> HashMap<String, Value> {
+) -> Result<HashMap<String, Value>, TripoError> {
     let mut extra = HashMap::new();
     if let Some(value) = texture_version {
-        extra.insert(
-            EXTRA_TEXTURE_VERSION.into(),
-            Value::String(value.as_str().into()),
-        );
+        extra.insert(EXTRA_TEXTURE_VERSION.into(), Value::String(wire(&value)?));
     }
     if let Some(value) = delight {
         extra.insert(EXTRA_DELIGHT.into(), Value::Bool(value));
     }
-    extra
+    Ok(extra)
 }
diff --git a/server-rs/crates/platform-tripo/src/common/mod.rs b/server-rs/crates/platform-tripo/src/common/mod.rs
index 5529bb3da..0d3b8a4d7 100644
--- a/server-rs/crates/platform-tripo/src/common/mod.rs
+++ b/server-rs/crates/platform-tripo/src/common/mod.rs
@@ -5,6 +5,7 @@ mod extra;
 mod mapping;
 mod types;
 mod validation;
+mod wire;
 
 pub use client::TripoProviderClient;
 pub use config::TripoSettings;
@@ -18,3 +19,4 @@ pub use types::{
 pub(crate) use validation::{
     TripoGenerationOptions, validate_generation_options, validate_task_id,
 };
+pub(crate) use wire::{wire, wire_option};
diff --git a/server-rs/crates/platform-tripo/src/common/wire.rs b/server-rs/crates/platform-tripo/src/common/wire.rs
new file mode 100644
index 000000000..64aa5b30f
--- /dev/null
+++ b/server-rs/crates/platform-tripo/src/common/wire.rs
@@ -0,0 +1,25 @@
+//! 契约枚举 → provider 请求里要发的线上取值。
+//!
+//! 取值只由 `shared-contracts` 里的 serde `rename` / `rename_all` 定义：provider 侧
+//! 不再维护第二份字面量，两处各写一份、改一处就静默分叉的问题不会再出现。
+
+use serde::Serialize;
+
+use super::TripoError;
+
+/// 契约枚举 → provider 线上取值。
+///
+/// 契约枚举都是「序列化成字符串」的形态；真拿到非字符串说明契约被改坏，这里归一成
+/// provider 内部错误，而不是 panic 或静默兜底。
+pub(crate) fn wire<T: Serialize + ?Sized>(value: &T) -> Result<String, TripoError> {
+    shared_contracts::model3d::wire_str(value).map_err(|error| TripoError::Sdk {
+        message: format!("契约枚举未按字符串序列化：{error}"),
+    })
+}
+
+/// [`wire`] 的 `Option` 形态：缺省仍是缺省。
+pub(crate) fn wire_option<T: Serialize + ?Sized>(
+    value: Option<&T>,
+) -> Result<Option<String>, TripoError> {
+    value.map(wire).transpose()
+}
diff --git a/server-rs/crates/platform-tripo/src/image_to_model/client.rs b/server-rs/crates/platform-tripo/src/image_to_model/client.rs
index 0c17d84bb..5c7fbf923 100644
--- a/server-rs/crates/platform-tripo/src/image_to_model/client.rs
+++ b/server-rs/crates/platform-tripo/src/image_to_model/client.rs
@@ -1,13 +1,9 @@
-use shared_contracts::model3d::common::{
-    Model3dCompression, Model3dExportOrientation, Model3dGeometryQuality, Model3dInputOrientation,
-    Model3dTextureAlignment, Model3dTextureQuality,
-};
 use shared_contracts::model3d::image_to_model::Model3dImageToModelParams;
 use tripo3d_sdk::{models::FileInput, params::ImageToModelParams};
 
 use crate::common::{
     TripoError, TripoField, TripoProviderClient, TripoTaskHandle, TripoValidationReason,
-    extra_fields,
+    extra_fields, wire, wire_option,
 };
 
 use super::validation::validate_image_to_model_params;
@@ -101,53 +97,38 @@ impl TripoProviderClient {
 
         let task_id = self
             .client
-            .image_to_model(to_sdk_params(input, params))
+            .image_to_model(to_sdk_params(input, params)?)
             .await
             .map_err(TripoError::from)?;
         Ok(TripoTaskHandle { task_id })
     }
 }
 
-fn to_sdk_params(input: FileInput, params: &Model3dImageToModelParams) -> ImageToModelParams {
-    ImageToModelParams {
+fn to_sdk_params(
+    input: FileInput,
+    params: &Model3dImageToModelParams,
+) -> Result<ImageToModelParams, TripoError> {
+    Ok(ImageToModelParams {
         input,
-        model: Some(params.model.as_str().to_owned()),
+        model: Some(wire(&params.model)?),
         enable_image_autofix: params.enable_image_autofix,
         model_seed: params.model_seed,
         texture_seed: params.texture_seed,
         texture: params.texture,
         pbr: params.pbr,
-        texture_quality: params
-            .texture_quality
-            .map(Model3dTextureQuality::as_str)
-            .map(str::to_owned),
-        extra: extra_fields(params.texture_version, params.delight),
-        texture_alignment: params
-            .texture_alignment
-            .map(Model3dTextureAlignment::as_str)
-            .map(str::to_owned),
-        geometry_quality: params
-            .geometry_quality
-            .map(Model3dGeometryQuality::as_str)
-            .map(str::to_owned),
+        texture_quality: wire_option(params.texture_quality.as_ref())?,
+        extra: extra_fields(params.texture_version, params.delight)?,
+        texture_alignment: wire_option(params.texture_alignment.as_ref())?,
+        geometry_quality: wire_option(params.geometry_quality.as_ref())?,
         face_limit: params.face_limit,
         auto_size: params.auto_size,
-        orientation: params
-            .orientation
-            .map(Model3dInputOrientation::as_str)
-            .map(str::to_owned),
+        orientation: wire_option(params.orientation.as_ref())?,
         quad: params.quad,
         smart_low_poly: params.smart_low_poly,
         generate_parts: params.generate_parts,
-        compress: params
-            .compress
-            .map(Model3dCompression::as_str)
-            .map(str::to_owned),
+        compress: wire_option(params.compress.as_ref())?,
         export_uv: params.export_uv,
-        export_orientation: params
-            .export_orientation
-            .map(Model3dExportOrientation::as_str)
-            .map(str::to_owned),
+        export_orientation: wire_option(params.export_orientation.as_ref())?,
         style: None,
-    }
+    })
 }
diff --git a/server-rs/crates/platform-tripo/src/multiview_to_model/client.rs b/server-rs/crates/platform-tripo/src/multiview_to_model/client.rs
index 7de1e63bf..3d526f244 100644
--- a/server-rs/crates/platform-tripo/src/multiview_to_model/client.rs
+++ b/server-rs/crates/platform-tripo/src/multiview_to_model/client.rs
@@ -1,7 +1,3 @@
-use shared_contracts::model3d::common::{
-    Model3dCompression, Model3dExportOrientation, Model3dGeometryQuality, Model3dInputOrientation,
-    Model3dTextureAlignment, Model3dTextureQuality,
-};
 use shared_contracts::model3d::multiview_to_model::{
     Model3dMultiviewInputs, Model3dMultiviewToModelRequest,
 };
@@ -9,7 +5,8 @@ use tripo3d_sdk::{models::FileInput, params::MultiviewToModelParams};
 
 use crate::common::{
     TripoError, TripoField, TripoGenerationOptions, TripoProviderClient, TripoTaskHandle,
-    TripoValidationReason, extra_fields, validate_generation_options, validate_task_id,
+    TripoValidationReason, extra_fields, validate_generation_options, validate_task_id, wire,
+    wire_option,
 };
 
 impl TripoProviderClient {
@@ -66,7 +63,7 @@ impl TripoProviderClient {
         })?;
         let task_id = self
             .client
-            .multiview_to_model(to_sdk_params(request))
+            .multiview_to_model(to_sdk_params(request)?)
             .await
             .map_err(TripoError::from)?;
         Ok(TripoTaskHandle { task_id })
@@ -80,7 +77,9 @@ fn optional_view(value: &Option<String>) -> Option<FileInput> {
         .map(|value| FileInput::from(value.trim()))
 }
 
-fn to_sdk_params(request: &Model3dMultiviewToModelRequest) -> MultiviewToModelParams {
+fn to_sdk_params(
+    request: &Model3dMultiviewToModelRequest,
+) -> Result<MultiviewToModelParams, TripoError> {
     let mut params = match &request.inputs {
         Model3dMultiviewInputs::Views {
             front,
@@ -97,41 +96,23 @@ fn to_sdk_params(request: &Model3dMultiviewToModelRequest) -> MultiviewToModelPa
             MultiviewToModelParams::from_task_id(task_id.trim().to_owned())
         }
     };
-    params.model = Some(request.model.as_str().to_owned());
+    params.model = Some(wire(&request.model)?);
     params.model_seed = request.model_seed;
     params.texture_seed = request.texture_seed;
     params.texture = request.texture;
     params.pbr = request.pbr;
-    params.texture_quality = request
-        .texture_quality
-        .map(Model3dTextureQuality::as_str)
-        .map(str::to_owned);
-    params.extra = extra_fields(request.texture_version, request.delight);
-    params.geometry_quality = request
-        .geometry_quality
-        .map(Model3dGeometryQuality::as_str)
-        .map(str::to_owned);
-    params.texture_alignment = request
-        .texture_alignment
-        .map(Model3dTextureAlignment::as_str)
-        .map(str::to_owned);
+    params.texture_quality = wire_option(request.texture_quality.as_ref())?;
+    params.extra = extra_fields(request.texture_version, request.delight)?;
+    params.geometry_quality = wire_option(request.geometry_quality.as_ref())?;
+    params.texture_alignment = wire_option(request.texture_alignment.as_ref())?;
     params.face_limit = request.face_limit;
     params.auto_size = request.auto_size;
-    params.orientation = request
-        .orientation
-        .map(Model3dInputOrientation::as_str)
-        .map(str::to_owned);
+    params.orientation = wire_option(request.orientation.as_ref())?;
     params.quad = request.quad;
     params.smart_low_poly = request.smart_low_poly;
     params.generate_parts = request.generate_parts;
-    params.compress = request
-        .compress
-        .map(Model3dCompression::as_str)
-        .map(str::to_owned);
+    params.compress = wire_option(request.compress.as_ref())?;
     params.export_uv = request.export_uv;
-    params.export_orientation = request
-        .export_orientation
-        .map(Model3dExportOrientation::as_str)
-        .map(str::to_owned);
-    params
+    params.export_orientation = wire_option(request.export_orientation.as_ref())?;
+    Ok(params)
 }
diff --git a/server-rs/crates/platform-tripo/src/text_to_model/client.rs b/server-rs/crates/platform-tripo/src/text_to_model/client.rs
index fa11c5755..11b09f7c9 100644
--- a/server-rs/crates/platform-tripo/src/text_to_model/client.rs
+++ b/server-rs/crates/platform-tripo/src/text_to_model/client.rs
@@ -1,6 +1,5 @@
-use crate::common::{TripoError, TripoProviderClient, TripoTaskHandle, extra_fields};
-use shared_contracts::model3d::common::{
-    Model3dCompression, Model3dExportOrientation, Model3dGeometryQuality, Model3dTextureQuality,
+use crate::common::{
+    TripoError, TripoProviderClient, TripoTaskHandle, extra_fields, wire, wire_option,
 };
 use shared_contracts::model3d::text_to_model::Model3dTextToModelParams;
 
@@ -14,46 +13,36 @@ impl TripoProviderClient {
         validate_text_to_model_params(params)?;
         let task_id = self
             .client
-            .text_to_model(to_sdk_params(params))
+            .text_to_model(to_sdk_params(params)?)
             .await
             .map_err(TripoError::from)?;
         Ok(TripoTaskHandle { task_id })
     }
 }
 
-fn to_sdk_params(params: &Model3dTextToModelParams) -> tripo3d_sdk::params::TextToModelParams {
-    tripo3d_sdk::params::TextToModelParams {
+fn to_sdk_params(
+    params: &Model3dTextToModelParams,
+) -> Result<tripo3d_sdk::params::TextToModelParams, TripoError> {
+    Ok(tripo3d_sdk::params::TextToModelParams {
         prompt: params.prompt.clone(),
-        model: Some(params.model.as_str().to_owned()),
+        model: Some(wire(&params.model)?),
         negative_prompt: params.negative_prompt.clone(),
         image_seed: params.image_seed,
         model_seed: params.model_seed,
         texture_seed: params.texture_seed,
         texture: params.texture,
         pbr: params.pbr,
-        texture_quality: params
-            .texture_quality
-            .map(Model3dTextureQuality::as_str)
-            .map(str::to_owned),
-        extra: extra_fields(params.texture_version, params.delight),
-        geometry_quality: params
-            .geometry_quality
-            .map(Model3dGeometryQuality::as_str)
-            .map(str::to_owned),
+        texture_quality: wire_option(params.texture_quality.as_ref())?,
+        extra: extra_fields(params.texture_version, params.delight)?,
+        geometry_quality: wire_option(params.geometry_quality.as_ref())?,
         face_limit: params.face_limit,
         auto_size: params.auto_size,
         quad: params.quad,
         smart_low_poly: params.smart_low_poly,
         generate_parts: params.generate_parts,
-        compress: params
-            .compress
-            .map(Model3dCompression::as_str)
-            .map(str::to_owned),
+        compress: wire_option(params.compress.as_ref())?,
         export_uv: params.export_uv,
-        export_orientation: params
-            .export_orientation
-            .map(Model3dExportOrientation::as_str)
-            .map(str::to_owned),
+        export_orientation: wire_option(params.export_orientation.as_ref())?,
         style: None,
-    }
+    })
 }
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/compression.rs b/server-rs/crates/shared-contracts/src/model3d/common/compression.rs
index 2fda58d5f..f32d2e1f6 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/compression.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/compression.rs
@@ -8,11 +8,3 @@ pub enum Model3dCompression {
     #[serde(rename = "geometry")]
     Geometry,
 }
-
-impl Model3dCompression {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::Geometry => "geometry",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/export_orientation.rs b/server-rs/crates/shared-contracts/src/model3d/common/export_orientation.rs
index 1657ef898..7fa8109ca 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/export_orientation.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/export_orientation.rs
@@ -14,14 +14,3 @@ pub enum Model3dExportOrientation {
     #[serde(rename = "-y")]
     MinusY,
 }
-
-impl Model3dExportOrientation {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::PlusX => "+x",
-            Self::MinusX => "-x",
-            Self::PlusY => "+y",
-            Self::MinusY => "-y",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/geometry_quality.rs b/server-rs/crates/shared-contracts/src/model3d/common/geometry_quality.rs
index bf2cfda39..a99860a76 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/geometry_quality.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/geometry_quality.rs
@@ -10,12 +10,3 @@ pub enum Model3dGeometryQuality {
     Standard,
     Detailed,
 }
-
-impl Model3dGeometryQuality {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::Standard => "standard",
-            Self::Detailed => "detailed",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/input_orientation.rs b/server-rs/crates/shared-contracts/src/model3d/common/input_orientation.rs
index 96517ea8d..393be2331 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/input_orientation.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/input_orientation.rs
@@ -10,12 +10,3 @@ pub enum Model3dInputOrientation {
     Default,
     AlignImage,
 }
-
-impl Model3dInputOrientation {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::Default => "default",
-            Self::AlignImage => "align_image",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/model_version.rs b/server-rs/crates/shared-contracts/src/model3d/common/model_version.rs
index 4e905abdd..0dc1255df 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/model_version.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/model_version.rs
@@ -20,14 +20,4 @@ pub enum Model3dModelVersion {
 impl Model3dModelVersion {
     /// 契约支持的全部模型版本；定价配置必须为每个版本给出两个端点的底价。
     pub const ALL: [Self; 5] = [Self::H31, Self::H30, Self::H25, Self::P1, Self::P2];
-
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::H31 => "v3.1-20260211",
-            Self::H30 => "v3.0-20250812",
-            Self::H25 => "v2.5-20250123",
-            Self::P1 => "P1-20260311",
-            Self::P2 => "P2-20260801",
-        }
-    }
 }
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/texture_alignment.rs b/server-rs/crates/shared-contracts/src/model3d/common/texture_alignment.rs
index 1c87c36b8..789d7f9d4 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/texture_alignment.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/texture_alignment.rs
@@ -10,12 +10,3 @@ pub enum Model3dTextureAlignment {
     OriginalImage,
     Geometry,
 }
-
-impl Model3dTextureAlignment {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::OriginalImage => "original_image",
-            Self::Geometry => "geometry",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/texture_quality.rs b/server-rs/crates/shared-contracts/src/model3d/common/texture_quality.rs
index b1f77ac97..bb95dab97 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/texture_quality.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/texture_quality.rs
@@ -12,14 +12,3 @@ pub enum Model3dTextureQuality {
     Detailed,
     Extreme,
 }
-
-impl Model3dTextureQuality {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::Fast => "fast",
-            Self::Standard => "standard",
-            Self::Detailed => "detailed",
-            Self::Extreme => "extreme",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/common/texture_version.rs b/server-rs/crates/shared-contracts/src/model3d/common/texture_version.rs
index 847b94c04..724d00295 100644
--- a/server-rs/crates/shared-contracts/src/model3d/common/texture_version.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/common/texture_version.rs
@@ -12,13 +12,3 @@ pub enum Model3dTextureVersion {
     #[serde(rename = "v2.5-20250123")]
     V25,
 }
-
-impl Model3dTextureVersion {
-    pub const fn as_str(self) -> &'static str {
-        match self {
-            Self::V35 => "v3.5-20260815",
-            Self::V30 => "v3.0-20250812",
-            Self::V25 => "v2.5-20250123",
-        }
-    }
-}
diff --git a/server-rs/crates/shared-contracts/src/model3d/mod.rs b/server-rs/crates/shared-contracts/src/model3d/mod.rs
index 6d6708bf1..657dd6a19 100644
--- a/server-rs/crates/shared-contracts/src/model3d/mod.rs
+++ b/server-rs/crates/shared-contracts/src/model3d/mod.rs
@@ -24,3 +24,32 @@ pub mod text_to_model;
 pub use generation_result::Model3dGenerationResult;
 
 pub const MODEL3D_CONTRACT_VERSION: &str = "model3d.v1";
+
+/// 契约枚举的线上取值。
+///
+/// 取值只由枚举上的 serde `rename` / `rename_all` 定义：调用方需要字符串时走这里，
+/// 不要在枚举旁边再手写一份 `as_str` —— 同一份取值出现两处，改一处就会静默分叉。
+/// 契约里的枚举都是「序列化成字符串」的形态；序列化失败或形态不符说明契约被改坏，
+/// 因此按错误返回，而不是 panic 或静默兜底。
+pub fn wire_str<T>(value: &T) -> Result<String, serde_json::Error>
+where
+    T: serde::Serialize + ?Sized,
+{
+    match serde_json::to_value(value)? {
+        serde_json::Value::String(text) => Ok(text),
+        other => Err(serde::ser::Error::custom(format!(
+            "model3d 契约枚举应序列化成字符串，实际为 {other}"
+        ))),
+    }
+}
+
+/// 与 [`wire_str`] 相同，但失败时退回 `Debug` 名称。
+///
+/// 只用于日志与审计文案：这些位置必须给出字符串且不能失败，退回值明显不是线上取值，
+/// 不会被误当成正常结果。
+pub fn wire_str_lossy<T>(value: &T) -> String
+where
+    T: serde::Serialize + std::fmt::Debug + ?Sized,
+{
+    wire_str(value).unwrap_or_else(|_| format!("{value:?}"))
+}
diff --git a/server-rs/crates/shared-contracts/tests/model3d_multiview_request_contract.rs b/server-rs/crates/shared-contracts/tests/model3d_multiview_request_contract.rs
index c67bf35cc..de52020ac 100644
--- a/server-rs/crates/shared-contracts/tests/model3d_multiview_request_contract.rs
+++ b/server-rs/crates/shared-contracts/tests/model3d_multiview_request_contract.rs
@@ -69,7 +69,7 @@ fn multiview_inputs_reject_unknown_fields_inside_variants() {
 fn multiview_request_rejects_unknown_top_level_fields() {
     let error = serde_json::from_value::<Model3dMultiviewToModelRequest>(json!({
         "inputs": { "kind": "taskId", "taskId": "tripo-task-1" },
-        "model": Model3dModelVersion::H31.as_str(),
+        "model": "v3.1-20260211",
         "unexpected": true
     }))
     .expect_err("请求体顶层出现未知字段应被拒绝");