feat(cli): add adk graph command and --ascii-only option for DOT output

[kamalraj23]

Close issue #3426

This adds a small-but-useful CLI feature for agent debugging and docs.

• New command: adk graph <agent_dir> --format dot|png|svg [--out path]
• New flag: --ascii-only (DOT output only) to strip Unicode icons for Windows CMD

Usage:

python -m google.adk.cli graph contributing\samples\hello_world --format dot --ascii-only --out graph.dot
python -m google.adk.cli graph contributing\samples\hello_world --format png --out hello.png (requires Graphviz)

Testing Plan

Environment:
Windows 10/11, Python 3.12 venv
Repo installed editable: pip install -e ".[test,eval,a2a]"
Optional for images: winget install Graphviz.Graphviz

DOT output (no Graphviz needed):

python -m google.adk.cli graph contributing\samples\hello_world --format dot --ascii-only --out graph.dot
Verify:
type graph.dot | more
Expect: strict digraph { ... hello_world_agent, roll_die, check_prime ... }
Without ascii-only (UTF-8 console), optional:
chcp 65001
set PYTHONIOENCODING=utf-8
python -m google.adk.cli graph contributing\samples\hello_world --format dot --out graph.dot

PNG/SVG (requires Graphviz):

python -m google.adk.cli graph contributing\samples\hello_world --format png --out hello.png
dir hello.png (file exists)

Negative test:

python -m google.adk.cli graph invalid\path --format dot
Expect a clear error about the path not existing.

No breaking changes:

adk run, adk web still work as before (unchanged).

Formatting:

python -m isort src tests contributing
python -m pyink --config pyproject.toml src tests contributing

[gemini-code-assist]

Summary of Changes

Hello @kamalraj23, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the Agent Development Kit's command-line interface by introducing a new "graph" command. This feature allows developers to generate visual representations of their agent structures, which is invaluable for debugging complex agent flows and creating clear documentation. It supports various output formats, including DOT, PNG, and SVG, and includes a specific option to ensure compatibility for DOT output on Windows systems.

Highlights

• New CLI Command: "adk graph": Introduces a new command-line interface command "adk graph" to visualize agent structures, aiding in debugging and documentation.
• Multiple Output Formats: The "adk graph" command supports outputting agent graphs in DOT (text), PNG, and SVG formats, providing flexibility for different use cases.
• Windows Compatibility for DOT Output: Adds an "--ascii-only" flag for the "adk graph" command when outputting in DOT format, which strips non-ASCII characters to ensure compatibility with Windows command prompts that may not render Unicode correctly.

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[adk-bot]

Response from ADK Triaging Agent

Hello @kamalraj23, thank you for creating this PR!

This PR is a new feature, could you please associate the github issue with this PR? If there is no existing issue, could you please create one?

In addition, could you please provide a testing plan section in your PR to talk about how you will test?

This information will help reviewers to review your PR more efficiently. Thanks!

[gemini-code-assist]

Code Review

This pull request introduces a new adk graph command to the CLI, which is a great feature for debugging and documentation. The implementation is solid, but I have a couple of suggestions to improve robustness and code clarity. Specifically, I recommend using pathlib for more reliable path manipulation and simplifying the logic for stripping non-ASCII characters.

[ryanaiagent]

Hi @kamalraj23, Thank you for your work on this pull request. We appreciate the effort you've invested.
It looks like the automated code formatting check failed. You can use autoformat.sh to fix it.