Cohere Upgrade & Migration

Overview

Guide for migrating from Cohere API v1 to v2 and upgrading the cohere-ai TypeScript / cohere Python SDK. Covers every breaking change with before/after code.

Prerequisites

• Current Cohere SDK installed
• Git for version control
• Test suite available

Instructions

Step 1: Check Current Version

# TypeScript
npm list cohere-ai

# Python
pip show cohere

# Latest versions
npm view cohere-ai version
pip index versions cohere

Step 2: Create Upgrade Branch

git checkout -b upgrade/cohere-v2-migration
npm install cohere-ai@latest
# or: pip install cohere --upgrade

Step 3: API v1 to v2 Breaking Changes

Client Import

// v1
import { CohereClient } from 'cohere-ai';
const cohere = new CohereClient({ token: '...' });

// v2
import { CohereClientV2 } from 'cohere-ai';
const cohere = new CohereClientV2({ token: '...' });

Chat Endpoint — Messages Format

// v1 — single message string
const response = await cohere.chat({
  message: 'Hello',
  preamble: 'You are helpful.',
  chatHistory: [
    { role: 'USER', message: 'Hi' },
    { role: 'CHATBOT', message: 'Hello!' },
  ],
});
console.log(response.text);

// v2 — OpenAI-compatible messages array, model required
const response = await cohere.chat({
  model: 'command-a-03-2025',  // REQUIRED in v2
  messages: [
    { role: 'system', content: 'You are helpful.' },
    { role: 'user', content: 'Hi' },
    { role: 'assistant', content: 'Hello!' },
    { role: 'user', content: 'Hello' },
  ],
});
console.log(response.message?.content?.[0]?.text);

Role Names

v1	v2
USER	user
CHATBOT	assistant
SYSTEM	system
TOOL	tool

Embed Endpoint — Required Fields

// v1 — model optional, no embedding_types
const response = await cohere.embed({
  texts: ['hello'],
});

// v2 — model, inputType, embeddingTypes all REQUIRED
const response = await cohere.embed({
  model: 'embed-v4.0',          // Required
  texts: ['hello'],
  inputType: 'search_document', // Required for v3+ models
  embeddingTypes: ['float'],    // Required for v3+ models
});

Rerank Endpoint — Model Required

// v1
const response = await cohere.rerank({
  query: 'best language',
  documents: ['Python', 'Rust'],
});

// v2
const response = await cohere.rerank({
  model: 'rerank-v3.5',  // Required
  query: 'best language',
  documents: ['Python', 'Rust'],
  topN: 2,
});

Classify Endpoint — Model Required

// v1
const response = await cohere.classify({
  inputs: ['great product'],
  examples: [/*...*/],
});

// v2
const response = await cohere.classify({
  model: 'embed-english-v3.0',  // Required
  inputs: ['great product'],
  examples: [/*...*/],
});

Streaming Changes

// v1
const stream = cohere.chatStream({ message: 'hello' });
for await (const event of stream) {
  if (event.eventType === 'text-generation') {
    process.stdout.write(event.text);
  }
}

// v2
const stream = await cohere.chatStream({
  model: 'command-a-03-2025',
  messages: [{ role: 'user', content: 'hello' }],
});
for await (const event of stream) {
  if (event.type === 'content-delta') {
    process.stdout.write(event.delta?.message?.content?.text ?? '');
  }
}

RAG / Documents

// v1 — connectors or documents as strings
const response = await cohere.chat({
  message: 'question',
  documents: [{ title: 'Doc', snippet: 'content' }],
  connectors: [{ id: 'web-search' }],
});
// citations via response.citations

// v2 — documents as data objects
const response = await cohere.chat({
  model: 'command-a-03-2025',
  messages: [{ role: 'user', content: 'question' }],
  documents: [
    { id: 'doc1', data: { text: 'content' } },
  ],
});
// citations via response.message?.citations

Tool Use

// v1 — Cohere-specific format
const tools = [{
  name: 'get_weather',
  description: 'Get weather',
  parameterDefinitions: {
    city: { type: 'str', required: true },
  },
}];

// v2 — OpenAI-compatible format
const tools = [{
  type: 'function',
  function: {
    name: 'get_weather',
    description: 'Get weather',
    parameters: {
      type: 'object',
      properties: { city: { type: 'string' } },
      required: ['city'],
    },
  },
}];

Step 4: Model Name Updates

Old Name	Current Name	Status
command	command-r7b-12-2024	Use new ID
command-r	command-r-08-2024	Use new ID
command-r-plus	command-r-plus-08-2024	Use new ID
command-nightly	command-a-03-2025	Use Command A
embed-english-v3.0	embed-v4.0	Upgrade recommended
rerank-english-v3.0	rerank-v3.5	Upgrade recommended

Step 5: Python Migration

# v1
import cohere
co = cohere.Client(api_key="...")
response = co.chat(message="hello")
print(response.text)

# v2
import cohere
co = cohere.ClientV2()  # reads CO_API_KEY
response = co.chat(
    model="command-a-03-2025",
    messages=[{"role": "user", "content": "hello"}],
)
print(response.message.content[0].text)

Step 6: Run Tests and Verify

npm test
# Fix any type errors from changed response shapes
# Key changes: response.text → response.message?.content?.[0]?.text
#              response.citations → response.message?.citations

git add -A
git commit -m "chore: migrate to Cohere API v2"

Migration Codemod (Find & Replace)

# Find all v1 imports
grep -rn "CohereClient\b" src/ --include="*.ts" | grep -v "CohereClientV2"

# Find v1 chat calls
grep -rn "\.chat({" src/ --include="*.ts" -A2 | grep "message:"

# Find v1 response access
grep -rn "response\.text\b" src/ --include="*.ts"

# Find v1 streaming events
grep -rn "eventType.*text-generation" src/ --include="*.ts"

Output

• Updated SDK to latest version
• Migrated all endpoints from v1 to v2 format
• Updated model IDs to current names
• All tests passing against v2 API

Error Handling

Error After Migration	Cause	Fix
model is required	Missed adding model param	Add model to every call
response.text is undefined	v1 response shape	Use response.message?.content?.[0]?.text
embedding_types required	v2 embed requirement	Add embeddingTypes: ['float']
input_type required	v2 embed requirement	Add inputType: 'search_document'

Resources

• API v1 to v2 Migration Guide
• Cohere Deprecations
• Cohere Models Overview

Next Steps

For CI integration during upgrades, see cohere-ci-integration.