fix: agentcore dev overwrites otel exporter env var

[avi-alpert]

Description

agentcore dev unconditionally overwrites OTel env vars (OTEL_EXPORTER_OTLP_ENDPOINT, OTEL_EXPORTER_OTLP_PROTOCOL, etc.) with its own values, ignoring any the user has already configured. This breaks workflows where users have their own collector or instrumentation setup.

Previously the only workaround was --no-traces, which is confusing since the user does want tracing — just not our defaults.

Fix: In startOtelCollector, respect any OTel env vars the user has already set in process.env. We provide sensible defaults only for vars that aren't already configured. User's env always wins.

Related Issue

Closes #1009

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Manual test:

# Start a dummy OTLP receiver:
python3 ~/Desktop/dummy-otel-collector.py  # listens on :9999

# Run agent with external endpoint:
OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:9999 \
OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf \
AGENT_OBSERVABILITY_ENABLED=true \
agentcore dev -l --skip-deploy

# Invoke agent → dummy server receives traces

Unit test: Added otel-collector.test.ts — verifies endpoint passthrough vs default behavior. Test fails without the fix, passes with it.

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[github-actions]

Package Tarball

aws-agentcore-0.24.0.tgz

How to install

gh release download pr-1742-tarball --repo aws/agentcore-cli --pattern "*.tgz" --dir /tmp/pr-tarball
npm install -g /tmp/pr-tarball/aws-agentcore-0.24.0.tgz

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)