fix: remove docker info check from container runtime detection

[jesseturner21]

Problem

During agentcore deploy, the "Check dependencies" preflight calls detectContainerRuntime() which runs docker info. This command communicates with the Docker daemon through the Unix socket (/var/run/docker.sock). If the user isn't in the docker group, the OS prompts for a password — a confusing experience since the container runtime check is non-blocking (deploy falls back to CodeBuild for container builds anyway).

The same issue affects agentcore dev with Container agents and users of Colima (which uses the standard docker CLI binary).

Options considered

1. Remove docker info entirely — detect runtimes with which + --version only. If the daemon isn't running, the user finds out when they actually use it (docker build fails with a clear "Cannot connect to the Docker daemon" error).

2. Keep docker info but suppress the password prompt — not possible. The OS-level polkit/sudo prompt fires before our code can react to the result.

3. Keep docker info but catch the failure silently — same problem: the prompt appears before the command returns a result. We can't prevent it.

Solution

Option 1. Remove the docker info call from detectContainerRuntime() and rely on which + --version for binary detection. This matches the approach already used by detectContainerRuntimeSync() in src/lib/packaging/container.ts.

The tradeoff is losing the proactive "start Docker" hint when the daemon is down. But the docker build error message is clear enough, and avoiding a surprise password prompt is worth that tradeoff.

Changes

• Remove docker info probe from detectContainerRuntime()
• Remove notReadyRuntimes tracking (only populated by the docker info failure path)
• Remove getStartHint() helper and START_HINTS constant (only used to format notReadyRuntimes messages)
• Simplify requireContainerRuntime() to just throw "not found" if no runtime passes which + --version
• Simplify container-dev-server.ts prepare() to just check if runtime is null

Test plan

• Unit tests: 35/35 pass across detect.test.ts and container-dev-server.test.ts
• Full test suite: 3295/3295 pass
• TypeScript compilation: 0 errors
• Pre-commit hooks: eslint, prettier, secretlint, typecheck all pass
• Manual: detectContainerRuntime() returns Docker info via which + --version only (no password prompt)
• Manual: agentcore dev -l with Container agent — full flow completes (build, start, run) with no password prompt
• Manual: agentcore deploy with Container agent on a machine without docker group membership — verify no password prompt

[github-actions]

Package Tarball

aws-agentcore-0.8.0.tgz

How to install

npm install https://github.com/aws/agentcore-cli/releases/download/pr-829-tarball/aws-agentcore-0.8.0.tgz

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	44.54%	7051 / 15828
🔵	Statements	44.01%	7480 / 16993
🔵	Functions	41.98%	1262 / 3006
🔵	Branches	43.52%	4734 / 10876

Generated in workflow #1736 for commit 4a00013 by the Vitest Coverage Report Action

[aidandaly24]

this lgtm approved