feat(telemetry): support env var override

[Hweinstock]

Problem

CI is emitting telemetry, and adding noise to the metrics.

Solution

• Add a AGENTCORE_TELEMETRY_DISABLED environment variable for disabling telemetry without config writes.
• Set that env var to true in the relevant CI jobs.

Testing

[ starting with a config.json with telemetry.enabled = true]
> AGENTCORE_TELEMETRY_DISABLED=1 agentcore config
{
  "telemetry": {
    "enabled": false,
    "audit": false,
    "endpoint": "https://telemetry.agentcore.aws.dev"
  },
  "installationId": "e92dbb9b-cd4f-4b9f-94cc-ef69d95087cb"
}

> agentcore config
{
  "telemetry": {
    "enabled": true,
    "audit": false,
    "endpoint": "https://telemetry.agentcore.aws.dev"
  },
  "installationId": "e92dbb9b-cd4f-4b9f-94cc-ef69d95087cb"
}

[agentcore-devx-automation]

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

[agentcore-devx-automation]

AgentCore Harness Review

Verdict: Changes requested

Thanks for adding the kill switch — the env-var handling, casing/trimming, and use of real temp dirs in tests all look good. One correctness concern:

AGENTCORE_TELEMETRY_DISABLED leaks into the persisted config

src/globalConfig/config.tsx (lines 25–39): the env-var override is applied inside applyOverrides, which is called by DefaultGlobalConfigAccessor.get(). This means the overridden value flows through any subsequent set() call and gets diffed against DEFAULT_GLOBAL_CONFIG before being written to disk (accessor.tsx, set() → diff(newConfig, DEFAULT_GLOBAL_CONFIG)).

Repro scenario:

1. User's on-disk config has telemetry.enabled: true (or is absent, and default is true).
2. User runs, e.g., AGENTCORE_TELEMETRY_DISABLED=1 agentcore config set telemetry.audit true — or any other command that ends up writing the global config.
3. The handler reads config via get() → telemetry.enabled is false (env override). It sets audit=true and writes the whole object back.
4. set() diffs against defaults and persists telemetry: { enabled: false, audit: true } to disk.
5. Next run without the env var set: telemetry.enabled is now false on disk, so telemetry stays disabled. The env var — which is documented as a transient override — has permanently flipped the user's config.

This is especially likely because the PR sets AGENTCORE_TELEMETRY_DISABLED=1 in the CI workflows; any test/CI path that writes the global config will now bake enabled: false into whatever it wrote.

Options to fix:

• Move the env-var check out of applyOverrides and into the telemetry consumer (e.g., wherever telemetry.enabled is actually read to decide whether to emit). That keeps the persisted config untouched.
• Keep the env-var check where it is, but have applyOverrides remember the "raw" pre-override value (or have set() re-read the on-disk value for telemetry.enabled when the env var is active) so the write path doesn't observe the override.
• Have set() explicitly strip the env-var-influenced fields before diffing/writing.

A regression test for "env var is set → run a config set on an unrelated key → on-disk file's telemetry.enabled is unchanged" would be worth adding alongside the fix.

Minor (non-blocking)

• Consider documenting AGENTCORE_TELEMETRY_DISABLED in the top-level README.md so users can discover it.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.22%. Comparing base (d304147) to head (d9e8563).
⚠️ Report is 2 commits behind head on refactor.

Additional details and impacted files

@@            Coverage Diff            @@
##           refactor    #2157   +/-   ##
=========================================
  Coverage     97.22%   97.22%           
=========================================
  Files           507      507           
  Lines         33809    33812    +3     
=========================================
+ Hits          32872    32875    +3     
  Misses          937      937           

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[Hweinstock]

Addressed harness reviewer comments by moving to telemetry. It would be great to handle this in the global config, but handling the edge case described introduces a ton of complexity.

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[jariy17]

Looks Good!