docs(examples): add policy condition-DSL string-operator example

[Karim Mehalebi (karimad)]

Related Issue

None

If no related issue is linked above, you must complete "Problem & Solution", "Impact on Your Work", and "Alternatives Considered" below.

Problem & Solution

Problem: PolicyRule's condition DSL gained contains/startswith/endswith operators in #3924, fixing a bug where those operators silently fell through to False (a deny rule using them never fired, with no warning). No example in the repo shows these operators in use, or demonstrates the fail-closed/fail-open semantics on non-string data that the fix also established.

Solution: adds examples/policy-condition-operators/README.md and a runnable string_operators.py — a minimal, dependency-free (beyond agent-governance-toolkit-core itself) example showing the three operators plus the before/after failure mode they replace, consistent with how other examples/ entries pair a README with a runnable script.

Impact on Your Work

Authored the underlying fix in #3924; this closes the documentation gap so other users adopting the new operators have a runnable reference.

Timeline

None

Alternatives Considered

None — this is additive documentation, no other approach considered.

Type of Change

• Documentation update

Package(s) Affected

• examples

Testing

Unit Testing

N/A — docs-only change, no new code paths.

Manual Testing

Ran examples/policy-condition-operators/string_operators.py directly (not just copy-pasted blocks) against the local agent-mesh source (post-#3924 fix), in an isolated venv with pydantic installed. All 9 print() outputs matched the inline comments exactly (True/False for each contains/startswith/endswith match/no-match case, plus the fail-closed deny-fires-on-non-string-or-missing-field cases and the fail-open-prevention allow-does-not-fire case). Log output confirmed the fail-closed/fail-open mechanism ('contains' cannot match — treating as MATCH/NO-MATCH).

Checklist

• I have linked a related issue above, or completed "Problem & Solution", "Impact on Your Work", and "Alternatives Considered"
• My code follows the project style guidelines (ruff check) — N/A, Markdown only
• I have added tests that prove my fix/feature works — N/A, docs-only
• All new and existing tests pass (pytest) — N/A, docs-only
• I have updated documentation as needed
• I have signed the Microsoft CLA

Attribution & Prior Art

• This contribution does not contain code copied or derived from other projects without attribution
• Any external projects that inspired this design are credited in code comments or documentation
• If this PR implements functionality similar to an existing open-source project, I have listed it below

Prior art / related projects (if any):
None

AI Assistance

• I can explain every meaningful change in this PR: what it does, why, and what tradeoffs were considered
• I have run tests and verification appropriate for this change
• No part of this PR was autonomously submitted by an AI agent without my review
• I have not used AI to generate review comments on others' PRs

If AI tools materially shaped this change, briefly note what was used:
Claude Code was used to draft the example and verify it against the real fixed source before submission; all content reviewed by me.

IP, Patents, and Licensing

• This contribution does not implement patent-pending or patent-encumbered techniques
• This contribution does not require an NDA or licensing agreement to understand or use
• Any AI tools used have terms compatible with the MIT License

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[github-actions]

PR Review Summary

Check	Status	Details
🔍 Code Review	⚠️ Missing	No current-run comment
🛡️ Security Scan	⚠️ Missing	No current-run comment
🔄 Breaking Changes	⚠️ Missing	No current-run comment
📝 Docs Sync	⚠️ Missing	No current-run comment
🧪 Test Coverage	⚠️ Missing	No current-run comment

Verdict: ⚠️ AI review incomplete; ready for human review

AI review comments are untrusted advisory output. The summary reports workflow-generated completion status only, not model-authored pass/fail claims.

[MohammadHaroonAbuomar]

Verified at 31a173e: the README install line now lists the packages the example needs, and running the documented commands literally in a clean Python 3.12 venv prints "All assertions passed" with exit 0. The check() helper fails loudly against the released 5.0.0 as asked, the unreleased-operators caveat is documented, both files carry the MIT header, and the commit is signed off. All checks green. Thanks for sticking with it.

[Kunal Bhagwat (toolstree)]

🔍 General Boring Work (github-research)
docs(examples): add policy condition-DSL string-operator example
#4020
Tier: Micro $1

Draft: Hi, saw "docs(examples): add policy condition-DSL string-operator example" — I do boring paperwork: memos, contracts, SOWs.
Set & forget, Telegram only, $1-$50 USDC. Want me to take this off your plate?

[Kunal Bhagwat (toolstree)]

Hi, saw "docs(examples): add policy condition-DSL string-operator example" — PR #4020 · microsoft/agent-governance-toolkit

I do boring paperwork: memos, contracts, SOWs. Set & forget, Telegram only, $1-$50 USDC. Want me to take this off your plate?

Start here:
https://t.me/Saturnking_bot?start=lead_4020