Langchain Prompt variable condition

[jung-han]

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Example Code

{prompt1}

{{prompt2}}

{prompt3}}}

{{{prompt4}}}

{{{{{prompt5}}}}}

{{{prompt6}

### Description



* some prompt variable work
<img width="1413" alt="image" src="https://github.com/langchain-ai/langchainjs/assets/35371660/5122cb3b-7606-4941-b5e2-9fabb861f821">


* all prompt not work
<img width="1426" alt="image" src="https://github.com/langchain-ai/langchainjs/assets/35371660/37b9af05-b31e-4a4a-beb6-60031b85dd1d">


Hi! Thank you for making a great tool.

I would like to inquire because I have a question while using langchain + langsmith.
In langchain, variables operate when they are wrapped in `{}`.
I was curious about how it works when multiple parentheses overlap, so I tested it.
In the above case, the variables are recognized only in certain cases, and in the case below, not all variables appear to be recognized.
Could you please let me know what the conditions are?
When using it in code, the error itself seems to occur when using `PromptTemplate.fromTemplate`.

I tried to refer to the inside of the code, but it is difficult to understand so I am asking a question. Thank you!

### System Info

langsmith / langchain mac 

[dosubot[bot]]

Hey there, @jung-han! 🚀 I'm Dosu, your friendly neighborhood bot, here to assist with bugs, answer questions, and guide you towards becoming a stellar contributor while our human maintainers are on their way. Don't worry, I've got your back in the meantime! I'm diving into your issue now and will get back to you with some insights shortly. Stay tuned! 🤖

[jung-han]

I can't see the image, so I'll post it as a comment.

• some prompt variable work

• all prompt not work

[KeenanFernandes2000]

not entirely sure if this is the intended functionality or if it's a bug, hope this helps. Also I'm not sure that the Dosu bot can help with issues that may happen on the langsmith platform

[dosubot]

It looks like you're encountering issues with variable recognition and formatting in LangChain and LangSmith, particularly when using PromptTemplate.fromTemplate. Here's a focused guide to address your concerns:

1. Template Syntax: Ensure you're using the correct syntax for your templates. LangChain supports "f-string" and "mustache" formats. For "f-string", variables should be enclosed in {}, while "mustache" format uses {{}}. Stick to one format in a template to avoid parsing errors.

2. Input Variables: Your input data structure must match the template's variable placeholders. This alignment is crucial for the template to correctly recognize and replace variables.

3. Error Handling: If you're seeing errors or inconsistencies, especially with "f-string" formatting, check for unmatched braces or incorrect variable types. LangChain's PromptTemplate class is designed to throw errors for invalid templates, which can help in identifying and resolving issues.

4. Serialization and Validation: The PromptTemplate class offers methods for serialization (serialize and deserialize) and validation. These features can be useful for persisting templates across sessions and ensuring your templates are correctly formatted before use.

For the specific inconsistencies you've noticed with f-string formatting in the UI, ensure that braces are correctly matched and understand that double braces are treated as literals. This understanding is key to avoiding common pitfalls with template formatting.

If you continue to face issues or have specific error messages, providing those details can help in offering more targeted advice.

Details

Sources

• langchain-core/src/prompts/tests/prompt.mustache.test.ts
• langchain-core/src/prompts/prompt.ts
• langchain-core/src/prompts/tests/prompt.test.ts
• langchain-core/src/prompts/tests/template.test.ts

About Dosu
This response is meant to be useful and save you time. It is not meant to be a precise solution, but rather a starting point for your own research.

Help me be more useful! Please leave a 👍 if this is helpful and 👎 if it is irrelevant.

To continue the conversation, mention @dosu.

[dosubot]

It looks like you're encountering issues with variable recognition and formatting in LangChain and LangSmith, particularly when using PromptTemplate.fromTemplate. Here's a focused guide to address your concerns:

1. Template Syntax: Ensure you're using the correct syntax for your templates. LangChain supports "f-string" and "mustache" formats. For "f-string", variables should be enclosed in {}, while "mustache" format uses {{}}. Stick to one format in a template to avoid parsing errors.

2. Input Variables: Your input data structure must match the template's variable placeholders. This alignment is crucial for the template to correctly recognize and replace variables.

3. Error Handling: If you're seeing errors or inconsistencies, especially with "f-string" formatting, check for unmatched braces or incorrect variable types. LangChain's PromptTemplate class is designed to throw errors for invalid templates, which can help in identifying and resolving issues.

4. Serialization and Validation: The PromptTemplate class offers methods for serialization (serialize and deserialize) and validation. These features can be useful for persisting templates across sessions and ensuring your templates are correctly formatted before use.

For the specific inconsistencies you've noticed with f-string formatting in the UI, ensure that braces are correctly matched and understand that double braces are treated as literals. This understanding is key to avoiding common pitfalls with template formatting.

If you continue to face issues or have specific error messages, providing those details can help in offering more targeted advice.

Details

Sources

• langchain-core/src/prompts/tests/prompt.mustache.test.ts
• langchain-core/src/prompts/prompt.ts
• langchain-core/src/prompts/tests/prompt.test.ts
• langchain-core/src/prompts/tests/template.test.ts

About Dosu
This response is meant to be useful and save you time. It is not meant to be a precise solution, but rather a starting point for your own research.

Help me be more useful! Please leave a 👍 if this is helpful and 👎 if it is irrelevant.

To continue the conversation, mention @dosu.

[dosubot]

It looks like you're encountering issues with variable recognition and formatting in LangChain and LangSmith, particularly when using PromptTemplate.fromTemplate. Here's a focused guide to address your concerns:

1. Template Syntax: Ensure you're using the correct syntax for your templates. LangChain supports "f-string" and "mustache" formats. For "f-string", variables should be enclosed in {}, while "mustache" format uses {{}}. Stick to one format in a template to avoid parsing errors.

2. Input Variables: Your input data structure must match the template's variable placeholders. This alignment is crucial for the template to correctly recognize and replace variables.

3. Error Handling: If you're seeing errors or inconsistencies, especially with "f-string" formatting, check for unmatched braces or incorrect variable types. LangChain's PromptTemplate class is designed to throw errors for invalid templates, which can help in identifying and resolving issues.

4. Serialization and Validation: The PromptTemplate class offers methods for serialization (serialize and deserialize) and validation. These features can be useful for persisting templates across sessions and ensuring your templates are correctly formatted before use.

For the specific inconsistencies you've noticed with f-string formatting in the UI, ensure that braces are correctly matched and understand that double braces are treated as literals. This understanding is key to avoiding common pitfalls with template formatting.

If you continue to face issues or have specific error messages, providing those details can help in offering more targeted advice.

Details

Sources

• langchain-core/src/prompts/tests/prompt.mustache.test.ts
• langchain-core/src/prompts/prompt.ts
• langchain-core/src/prompts/tests/prompt.test.ts
• langchain-core/src/prompts/tests/template.test.ts

About Dosu
This response is meant to be useful and save you time. It is not meant to be a precise solution, but rather a starting point for your own research.

Help me be more useful! Please leave a 👍 if this is helpful and 👎 if it is irrelevant.

To continue the conversation, mention @dosu.

[dosubot]

It looks like you're encountering issues with variable recognition and formatting in LangChain and LangSmith, particularly when using PromptTemplate.fromTemplate. Here's a focused guide to address your concerns:

1. Template Syntax: Ensure you're using the correct syntax for your templates. LangChain supports "f-string" and "mustache" formats. For "f-string", variables should be enclosed in {}, while "mustache" format uses {{}}. Stick to one format in a template to avoid parsing errors.

2. Input Variables: Your input data structure must match the template's variable placeholders. This alignment is crucial for the template to correctly recognize and replace variables.

3. Error Handling: If you're seeing errors or inconsistencies, especially with "f-string" formatting, check for unmatched braces or incorrect variable types. LangChain's PromptTemplate class is designed to throw errors for invalid templates, which can help in identifying and resolving issues.

4. Serialization and Validation: The PromptTemplate class offers methods for serialization (serialize and deserialize) and validation. These features can be useful for persisting templates across sessions and ensuring your templates are correctly formatted before use.

For the specific inconsistencies you've noticed with f-string formatting in the UI, ensure that braces are correctly matched and understand that double braces are treated as literals. This understanding is key to avoiding common pitfalls with template formatting.

If you continue to face issues or have specific error messages, providing those details can help in offering more targeted advice.

Details

Sources

• langchain-core/src/prompts/tests/prompt.mustache.test.ts
• langchain-core/src/prompts/prompt.ts
• langchain-core/src/prompts/tests/prompt.test.ts
• langchain-core/src/prompts/tests/template.test.ts

About Dosu
This response is meant to be useful and save you time. It is not meant to be a precise solution, but rather a starting point for your own research.

Help me be more useful! Please leave a 👍 if this is helpful and 👎 if it is irrelevant.

To continue the conversation, mention @dosu.