Claude Code 2.1.122 Lets You Pick a Bedrock Service Tier From an Env Var

The Claude Code v2.1.122 release on April 28, 2026 added a one-line knob that anyone running the agent on AWS Bedrock has been quietly waiting for: a new ANTHROPIC_BEDROCK_SERVICE_TIER environment variable that selects the Bedrock service tier on every request. Set it to default, flex, or priority, and the CLI forwards the value as the X-Amzn-Bedrock-Service-Tier header. No SDK code changes. No JSON config edits. One env var.

Why this matters even before you read the rest

AWS introduced the Priority and Flex inference tiers for Bedrock in November 2025 as a way to trade latency for cost. Per the Bedrock service-tiers page, Flex is a 50 percent discount versus Standard pricing in exchange for “increased latency”, and Priority is a 75 percent premium that jumps your requests to the front of the queue. For an agent like Claude Code that fires off long sequences of tool-use turns over the course of a session, the math is loud. A long evergreen task that ran on default could cost half as much on Flex if you can absorb the extra wall-clock time, and a debugging session where you are babysitting the terminal could feel snappier on Priority.

Until v2.1.122, the only way to pick a tier with Claude Code on Bedrock was to wrap the request layer yourself or proxy through something that could inject the header. The feature request issue that landed in this release closes that gap.

The actual usage

# Cheap background agents that triage issues overnight
export ANTHROPIC_BEDROCK_SERVICE_TIER=flex
claude --from-pr https://github.acme.internal/acme/api/pull/482

# Interactive debug session, paying for speed
export ANTHROPIC_BEDROCK_SERVICE_TIER=priority
claude

The CLI ships the value verbatim as X-Amzn-Bedrock-Service-Tier on the InvokeModel request, which is the same plumbing CloudTrail and CloudWatch already record under ServiceTier and ResolvedServiceTier. So if your platform team has dashboards on Bedrock spend by tier, the Claude Code traffic now lands in the right bucket without any extra work.

Watch out for ResolvedServiceTier

The header is a request, not a guarantee. AWS returns the tier it actually served you in ResolvedServiceTier, and Flex requests can be downgraded if the model’s flex pool is saturated. The full list of which models support Priority and Flex is on the Bedrock pricing page, and it lags the latest model launches by weeks, so confirm the model ID you are running with Claude Code is on it before you bake flex into a CI job. If a tier is unsupported, AWS falls back to the default tier transparently and bills you accordingly.

The ANTHROPIC_BEDROCK_SERVICE_TIER line is buried mid-changelog, but it is the cheapest cost lever on Bedrock-hosted Claude Code right now. Full notes are in the Claude Code v2.1.122 release page.