fix(rewoo): replace placeholder IFF type is str

[willkill07]

Description

We did not guard the string substitution of a placeholder.
This could cause a runtime error.

Closes

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Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Fixed a type-handling issue in placeholder replacement that could cause errors when processing non-string values, improving system stability and reliability.

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Walkthrough

Modified the _replace_placeholder function in the rewoo_agent to add a guard that ensures the value is a string before performing a placeholder membership check. This prevents potential TypeErrors when processing non-string values while maintaining the existing placeholder replacement logic.

Changes

Cohort / File(s)	Summary
Type guard in placeholder replacement src/nat/agent/rewoo_agent/agent.py	Added string type check before membership operation in _replace_placeholder to prevent TypeErrors on non-string values

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The pull request title "fix(rewoo): replace placeholder IFF type is str" is concise at 49 characters (well under the 72-character limit) and directly describes the main change in the changeset. The title accurately summarizes the core fix: adding a type guard to ensure string type verification before placeholder substitution, which aligns precisely with the code change that guards membership checks for string values. The title is specific and meaningful, clearly communicating the intent without vagueness or generic phrasing.

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📥 Commits

Reviewing files that changed from the base of the PR and between 36ba62c and ea8a0bd.

📒 Files selected for processing (1)

• src/nat/agent/rewoo_agent/agent.py (1 hunks)

🧰 Additional context used

📓 Path-based instructions (5)

**/*.py

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**/*.py: In code comments use the abbreviations: nat (API namespace/CLI), nvidia-nat (package), NAT (env var prefixes); never use these abbreviations in documentation
Follow PEP 20 and PEP 8 for Python style
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Files:

• src/nat/agent/rewoo_agent/agent.py

{src/**/*.py,packages/*/src/**/*.py}

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{src/**/*.py,packages/*/src/**/*.py}: All importable Python code must live under src/ or packages//src/
All public APIs must have Python 3.11+ type hints on parameters and return values
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Files:

• src/nat/agent/rewoo_agent/agent.py

src/nat/**/*

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src/nat/**/* contains core functionality; changes should prioritize backward compatibility

Files:

• src/nat/agent/rewoo_agent/agent.py

---

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Files:

• src/nat/agent/rewoo_agent/agent.py

{**/*.py,**/*.sh,**/*.md,**/*.toml,**/*.y?(a)ml,**/*.json,**/*.txt,**/*.ini,**/*.cfg,**/*.ipynb}

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Files:

• src/nat/agent/rewoo_agent/agent.py

**/*

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**/*: # Code Review Instructions

• Ensure the code follows best practices and coding standards. - For Python code, follow
  PEP 20 and
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• Check for security vulnerabilities and potential issues. - Python methods should use type hints for all parameters and return values.
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Files:

• src/nat/agent/rewoo_agent/agent.py

🔇 Additional comments (1)

src/nat/agent/rewoo_agent/agent.py (1)

220-220: LGTM! Critical bug fix.

The isinstance(value, str) guard correctly prevents a TypeError when value is a non-string type (e.g., int, float, bool) that doesn't support the in operator, or avoids unexpected behavior when value is a collection type (e.g., list, dict) where in has different semantics.

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[willkill07]

/merge