fix: centralize ANSI codes and disable colors in non-TTY output

[Hweinstock]

Description

Inline ANSI escape codes were scattered across the codebase and always emitted regardless of whether output was going to a terminal or a file. This caused garbled text when CLI output was redirected (e.g. agentcore import --source agent.yaml 2> log.txt).

This PR:

1. Centralizes all ANSI color codes into src/cli/constants.ts behind a shared ANSI object
2. Adds TTY detection and NO_COLOR support — colors auto-disable when output is piped or redirected
3. Removes the duplicate ANSI definition from src/cli/commands/import/constants.ts
4. Updates all call sites to import from the centralized constant

Terminal control sequences (alt screen, show cursor, clear line) remain unconditional since they are only used in TUI contexts that require a TTY.

Related Issue

Closes # #1391

Documentation PR

N/A

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 verification:

# Built and installed the bundled tarball
npm run bundle && npm install -g ./aws-agentcore-0.15.0-preview-*.tgz

# Confirmed no escape codes in redirected output
agentcore import --source /tmp/nonexistent.yaml 2> /tmp/err.txt
cat -v /tmp/err.txt
# Output: [error] Import failed: Source file not found: /tmp/nonexistent.yaml

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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terms of your choice.

[agentcore-devx-automation]

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

[github-actions]

Package Tarball

aws-agentcore-0.15.0.tgz

How to install

gh release download pr-1399-tarball --repo aws/agentcore-cli --pattern "*.tgz" --dir /tmp/pr-tarball
npm install -g /tmp/pr-tarball/aws-agentcore-0.15.0.tgz

[agentcore-cli-automation]

Thanks for centralizing ANSI handling and adding NO_COLOR support. I have one blocking concern about the TTY detection that I think defeats the very bug this PR aims to fix.

See inline comments. Happy to approve once the per-stream gating is addressed (or after we discuss).

[agentcore-cli-automation]

The OR-based TTY check defeats the redirect case this PR is trying to fix.

Consider the canonical scenario from the PR description:

agentcore import --source agent.yaml 2> log.txt

Here process.stdout.isTTY === true (terminal) and process.stderr.isTTY === undefined (file). The check evaluates to true || undefined === true, so useColor = true. All the new color writes that go to stderr (console.error in import/command.ts, printTelemetryNotice and printUpdateNotification writing to process.stderr) will still emit ANSI codes into log.txt. The exact case the PR description shows working should still be garbled.

A few options to fix:

1. Per-stream gating — expose two color sets (or a helper) keyed off the destination stream. e.g.

   const stdoutColor = !process.env.NO_COLOR && !!process.stdout.isTTY;
   const stderrColor = !process.env.NO_COLOR && !!process.stderr.isTTY;
   export const ANSI = { stdout: makeCodes(stdoutColor), stderr: makeCodes(stderrColor), control: { ... } };

   Call sites that write to stderr (console.error, process.stderr.write) use ANSI.stderr.red, etc.

2. AND instead of OR — process.stdout.isTTY && process.stderr.isTTY. Pessimistic but matches the spirit of the PR (any redirection disables colors everywhere). Simpler than option 1.

3. Adopt an existing library — e.g. the chalk / supports-color ecosystem already does this correctly per stream. May be overkill if you want to keep dependencies minimal.

Could you also add a test (or update the manual repro) that specifically exercises 2> with a TTY stdout? That would catch this regression.

[Hweinstock]

fixed and verified e2e by using the and approach.

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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

[agentcore-devx-automation]

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