Parallel Agent Optimization: PID Offset and Account Allocation

PID offset is a process ID-based account allocation optimization mechanism that calculates an offset via process.pid % accounts.length, allowing multiple OpenCode processes or oh-my-opencode parallel agents to prioritize selecting different Google accounts. When multiple processes run concurrently, each process automatically selects a different starting account based on the remainder of its PID, effectively avoiding 429 rate limit errors caused by multiple processes crowding the same account. This significantly improves request success rates and quota utilization in parallel scenarios, making it ideal for developers who need to run multiple Agents or parallel tasks simultaneously.

What You'll Learn

• Understand account conflicts in parallel agent scenarios
• Enable PID offset functionality to let different processes prioritize different accounts
• Coordinate with round-robin strategy to maximize multi-account utilization
• Troubleshoot rate limit and account selection issues in parallel agents

Your Current Challenge

When using oh-my-opencode or running multiple OpenCode instances simultaneously, you may encounter:

• Multiple sub-agents using the same account simultaneously, frequently hitting 429 rate limits
• Even with multiple accounts configured, concurrent requests still crowd the same account
• Different processes all start from the first account, causing uneven account allocation
• Long wait times before retrying after request failures

When to Use This

PID offset functionality is suitable for the following scenarios:

Scenario	Needs PID Offset?	Reason
Single OpenCode Instance	❌ No	Single process, no account conflicts
Manual Account Switching	❌ No	Non-concurrent, sticky strategy is sufficient
oh-my-opencode Multiple Agents	✅ Recommended	Multi-process concurrency, need to distribute accounts
Simultaneously Running Multiple OpenCode	✅ Recommended	Different processes have independent PIDs, automatic distribution
CI/CD Parallel Tasks	✅ Recommended	Each task is an independent process, avoids competition

Prerequisites Check

Before starting this tutorial, ensure you have completed:

• ✅ Configured at least 2 Google accounts
• ✅ Understood how account selection strategy works
• ✅ Using oh-my-opencode or need to run multiple OpenCode instances in parallel

Multi-Account Setup Tutorial | Account Selection Strategies Tutorial

Core Approach

What is PID Offset?

PID (Process ID) is a unique identifier assigned by the operating system to each process. When multiple OpenCode processes run simultaneously, each process has a different PID.

PID offset is a process ID-based account allocation optimization:

Assume there are 3 accounts (index: 0, 1, 2):

Process A (PID=123):
  123 % 3 = 0 → Prioritize account 0

Process B (PID=456):
  456 % 3 = 1 → Prioritize account 1

Process C (PID=789):
  789 % 3 = 2 → Prioritize account 2

Each process prioritizes a different account based on the remainder of its PID, avoiding crowding the same account from the start.

Why Do We Need PID Offset?

Without PID offset, all processes start from account 0:

Timeline:
T1: Process A starts → Uses account 0
T2: Process B starts → Uses account 0  ← Conflict!
T3: Process C starts → Uses account 0  ← Conflict!

With PID offset enabled:

Timeline:
T1: Process A starts → PID offset → Uses account 0
T2: Process B starts → PID offset → Uses account 1  ← Distributed!
T3: Process C starts → PID offset → Uses account 2  ← Distributed!

Coordination with Account Selection Strategy

PID offset only takes effect during the fallback phase of the sticky strategy (round-robin and hybrid strategies have their own allocation logic):

Strategy	PID Offset Effective?	Recommended Scenario
sticky	✅ Yes	Single process + prompt cache priority
round-robin	❌ No	Multi-process/parallel agents, max throughput
hybrid	❌ No	Intelligent allocation, health score priority

Why Doesn't round-robin Need PID Offset?

The round-robin strategy itself rotates accounts:

// Switch to next account for each request
this.cursor++;
const account = available[this.cursor % available.length];

Multiple processes will naturally distribute across different accounts without additional PID offset.

Best Practice

For parallel agent scenarios, recommended configuration:

{
  "account_selection_strategy": "round-robin",
  "pid_offset_enabled": false  // Not needed for round-robin
}

Only enable PID offset if you must use sticky or hybrid strategy.

Follow Along

Step 1: Confirm Multi-Account Configuration

Why PID offset requires at least 2 accounts to be effective. If there's only 1 account, regardless of the PID remainder, it can only use that account.

How

Check current account count:

opencode auth list

You should see at least 2 accounts:

2 account(s) saved:
  1. [email protected]
  2. [email protected]

If there's only 1 account, add more accounts first:

opencode auth login

Follow the prompts to select (a)dd new account(s).

You should see: Account list shows 2 or more accounts.

Step 2: Configure PID Offset

Why Enable PID offset functionality through configuration file so the plugin considers process ID during account selection.

How

Open the OpenCode configuration file:

• macOS/Linux: ~/.config/opencode/antigravity.json
• Windows: %APPDATA%\opencode\antigravity.json

Add or modify the following configuration:

{
  "pid_offset_enabled": true
}

Full configuration example (coordinated with sticky strategy):

{
  "pid_offset_enabled": true,
  "account_selection_strategy": "sticky"
}

Environment Variable Method (optional):

export OPENCODE_ANTIGRAVITY_PID_OFFSET_ENABLED=1

You should see: pid_offset_enabled set to true in configuration file.

Step 3: Verify PID Offset Effect

Why Verify PID offset is effective by running multiple processes and checking if different processes prioritize different accounts.

How

Open two terminal windows and run OpenCode separately:

Terminal 1:

opencode chat
# Send a request, record which account is used (check logs or toast)

Terminal 2:

opencode chat
# Send a request, record which account is used

Observe account selection behavior:

• ✅ Expected: Two terminals prioritize different accounts
• ❌ Problem: Both terminals use the same account

If the problem persists, check:

1. Whether configuration is loaded correctly
2. Whether account selection strategy is sticky (round-robin doesn't need PID offset)
3. Whether there's only 1 account

Enable debug logs to see detailed account selection process:

export OPENCODE_ANTIGRAVITY_DEBUG=1
opencode chat

Logs will show:

[accounts] Applying PID offset: 1 (process.pid % accounts.length)
[accounts] Starting account index for 'claude': 1

You should see: Different terminals prioritize different accounts, or logs show PID offset has been applied.

Step 4: (Optional) Coordinate with round-robin Strategy

Why The round-robin strategy itself rotates accounts and doesn't need PID offset. However, for high-frequency concurrent parallel agents, round-robin is the better choice.

How

Modify configuration file:

{
  "account_selection_strategy": "round-robin",
  "pid_offset_enabled": false
}

Start multiple oh-my-opencode Agents and observe request distribution:

Agent 1 → Account 0 → Account 1 → Account 2 → Account 0 ...
Agent 2 → Account 1 → Account 2 → Account 0 → Account 1 ...

Each Agent independently rotates, fully utilizing all accounts' quotas.

You should see: Requests evenly distributed across all accounts, each Agent independently rotating.

Checkpoint ✅

After completing the above steps, you should be able to:

• [ ] Successfully configure at least 2 Google accounts
• [ ] Enable pid_offset_enabled in antigravity.json
• [ ] When running multiple OpenCode instances, different processes prioritize different accounts
• [ ] Understand why round-robin doesn't need PID offset
• [ ] Use debug logs to view account selection process

Common Pitfalls

Problem 1: No Effect After Enabling

Symptoms: Configured pid_offset_enabled: true, but multiple processes still use the same account.

Causes: Account selection strategy might be round-robin or hybrid, both of which don't use PID offset.

Solutions: Switch to sticky strategy, or understand that current strategy doesn't need PID offset.

{
  "account_selection_strategy": "sticky",  // Change to sticky
  "pid_offset_enabled": true
}

Problem 2: Only 1 Account

Symptoms: After enabling PID offset, all processes still use account 0.

Causes: PID offset calculates via process.pid % accounts.length, and with only 1 account, the remainder is always 0.

Solutions: Add more accounts:

opencode auth login
# Select (a)dd new account(s)

Problem 3: Prompt Cache Invalidation

Symptoms: After enabling PID offset, Anthropic's prompt cache no longer takes effect.

Causes: PID offset may cause different processes or sessions to use different accounts, and prompt cache is shared per account. After switching accounts, prompts need to be resent.

Solutions: This is expected behavior. If prompt cache is higher priority, disable PID offset and use sticky strategy:

{
  "pid_offset_enabled": false,
  "account_selection_strategy": "sticky"
}

Problem 4: oh-my-opencode Multi-Agent Conflicts

Symptoms: Even with multiple accounts configured, oh-my-opencode's multiple Agents still frequently encounter 429 errors.

Causes: oh-my-opencode might start Agents sequentially, with multiple Agents simultaneously requesting the same account in a short time.

Solutions:

1. Use round-robin strategy (recommended):

{
  "account_selection_strategy": "round-robin"
}

2. Or increase account count to ensure each Agent has an independent account:

# If there are 3 Agents, recommend at least 5 accounts
opencode auth login

Summary

PID offset functionality optimizes account allocation in multi-process scenarios via process ID (PID):

• Principle: Calculate offset via process.pid % accounts.length
• Purpose: Let different processes prioritize different accounts, avoiding conflicts
• Limitation: Only effective under sticky strategy, round-robin and hybrid don't need it
• Best Practice: For parallel agent scenarios, recommend round-robin strategy, no PID offset needed

After configuring multiple accounts, choose the appropriate strategy based on your use case:

Scenario	Recommended Strategy	PID Offset
Single process, prompt cache priority	sticky	No
Multi-process/parallel agents	round-robin	No
hybrid strategy + staggered starts	hybrid	Optional

Next Lesson Preview

In the next lesson, we'll learn Complete Configuration Guide.

You'll learn:

• Configuration file location and priority
• Configuration options for model behavior, account rotation, and app behavior
• Recommended configuration schemes for different scenarios
• Advanced configuration tuning methods

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Appendix: Source Code Reference

Click to expand source code locations

Last updated: 2026-01-23

Feature	File Path	Lines
PID Offset Implementation	src/plugin/accounts.ts	388-393
Config Schema Definition	src/plugin/config/schema.ts	244-255
Environment Variable Support	src/plugin/config/loader.ts	163-168
Config Injection Point	src/plugin.ts	902
Usage Documentation	docs/MULTI-ACCOUNT.md	111-125
Configuration Guide	docs/CONFIGURATION.md	69

Key Functions:

• getCurrentOrNextForFamily(): Main account selection function, handles PID offset logic internally
• process.pid % this.accounts.length: Core formula for calculating offset

Key Constants:

• sessionOffsetApplied[family]: Offset application marker per model family (applied only once per session)