Upgrade Chat Model

Upgrades the AI model used in the chat app. There are two model slots:

• fast (Enter): default/fallback model (first entry in CHAT_MODELS)
• good (Cmd+Enter): smart mode model (second entry in CHAT_MODELS)

The user must specify which slot to upgrade and the new model name (e.g. Codex-opus-4-6).

Steps

1. Determine the change

Ask the user (if not already provided):

• Which slot: fast or good?
• What is the new model name? (e.g. Codex-opus-4-6)

Derive from the model name:

• SERDE_NAME: the kebab-case model ID sent over the wire (e.g. Codex-opus-4-6)
• ENUM_VARIANT: PascalCase variant name (e.g. Claude46Opus)
• CONST_NAME: SCREAMING_SNAKE constant name (e.g. CLAUDE_46_OPUS)
• CONST_VALUE: display string used by the frontend/provider (e.g. Codex-4.6-opus)
• PRETTY_NAME: human-readable name (e.g. Codex Opus 4.6)

2. Add model to AI crate (if it doesn't already exist)

File: crates/agent/src/model/predefined_model.rs

Check if the enum variant already exists. If not, add all of the following:

1. Enum variant in pub enum Model (under the Anthropic section):

   #[serde(rename = "{SERDE_NAME}")]
   #[strum(serialize = "{SERDE_NAME}")]
   {ENUM_VARIANT},
   

2. String constant in pub mod constants::models:

   pub const {CONST_NAME}: &str = "{CONST_VALUE}";
   

3. Match arm in to_provider_model_string():

   Model::{ENUM_VARIANT} => (ANTHROPIC, {CONST_NAME}),
   

4. Match arm in from_model_str():

   {CONST_NAME} => Model::{ENUM_VARIANT},
   

File: crates/agent/src/model/predefined_model.rs

5. Metadata in fn metadata():

   Model::{ENUM_VARIANT} => ModelMetadata {
       context_window: 200_000,
   },
   

   Use the correct context window for the model. Anthropic models are typically 200,000.

6. Provider in fn provider():

   Model::{ENUM_VARIANT} => Provider::Anthropic,
   

3. Update DCS constants

File: services/document_cognition_service/src/core/model.rs

• If upgrading the fast slot: change the first entry in CHAT_MODELS and update FALLBACK_MODEL.
• If upgrading the good slot: change the second entry in CHAT_MODELS.

4. Update DCS chat message handler

File: services/document_cognition_service/src/api/ws/chat_message/mod.rs

Search for the old model variant being used in the model selection logic (e.g. Model::Claude45Opus). Update it to the new variant.

5. Verify Rust compiles

cargo check -p agent -p document_cognition_service

Fix any compilation errors before proceeding.

6. Generate frontend types

Run from apps/web/:

cd apps/web && bun install && bun run gen-api

This builds all Rust OpenAPI and models binaries from local code, generates openapi.json, runs orval for TypeScript types, and generates model.ts from the local models binary. All generated files will reflect your local Rust changes.

7. Run bun check to find frontend usages

cd apps/web && bun check

This will report TypeScript errors everywhere the old model string is used. Fix each one. Common locations:

• apps/web/src/lib/core/component/AI/constant/model.ts — MODEL_PRETTYNAME, MODEL_PROVIDER_ICON, SMART_MODE_MODEL / DEFAULT_MODEL
• apps/web/src/lib/core/component/AI/component/input/useChatInput.tsx — hardcoded model references
• apps/web/src/lib/core/component/AI/signal/pendingSend.test.ts — test data

Replace old model strings and update display names.

8. Format and verify

cd apps/web && bun format && bun check

The only errors remaining should be pre-existing ones unrelated to models (e.g. three, @aws-crypto/sha256-js type issues). All model-related errors must be resolved.

Finally, run the CI check:

cd apps/web && bun run gen-api -- --check

This must pass.

Notes

• We only support Anthropic models for chat. Other providers exist in the AI crate but are not used for the chat feature.
• The ExhaustiveMap type in constant/model.ts requires an entry for every model in the Model type, so missing entries will cause type errors.
• The SMART_MODE_MODEL constant is the "good" model, DEFAULT_MODEL is the "fast" model.