Can all tool calls be parallelized?

Only independent ones. If tool B needs the output of tool A, they must run sequentially. The planning step determines which calls are independent. Example: 'get customer ID from email' (tool A) then 'look up order history for that customer ID' (tool B) must be sequential. But 'search knowledge base' and 'check CRM' can run in parallel because neither depends on the other's output.

Parallel Tool Execution

Written by Max Zeshut

Founder at Agentmelt · Last updated May 26, 2026

Running multiple tool calls simultaneously rather than sequentially to reduce AI agent latency. When an agent needs to query a CRM, search a knowledge base, and check a calendar, parallel execution does all three at once (300ms) instead of one after another (900ms). This is especially impactful for voice agents and real-time chat where users expect fast responses. Most modern agent frameworks support parallel tool execution natively.

Example

A sales agent preparing for a meeting needs to: (1) pull the prospect's CRM record, (2) check recent email exchanges, (3) search LinkedIn for updates, and (4) review the company's latest news. Sequentially, this takes 4 seconds. With parallel execution, all four queries run simultaneously and complete in 1.2 seconds—the latency of the slowest individual query.

Frequently asked questions

Can all tool calls be parallelized?: Only independent ones. If tool B needs the output of tool A, they must run sequentially. The planning step determines which calls are independent. Example: 'get customer ID from email' (tool A) then 'look up order history for that customer ID' (tool B) must be sequential. But 'search knowledge base' and 'check CRM' can run in parallel because neither depends on the other's output.

Related glossary terms

Related niches

Back to glossary

Loading…