Exceptions

Module: promptframe.exceptions

---

PromptNotFoundError

class PromptNotFoundError(KeyError)

Raised when a prompt pid cannot be found in a loaded YAML file. Includes a helpful message listing all available pids.

Constructor:

PromptNotFoundError(pid: str, available: List[str] | None = None)

Attributes:

Attribute	Type	Description
pid	str	The pid that was not found
available	List[str]	All pids present in the file

Raised by: PromptYAML.__getattr__(), PromptDataModelYAML.__getattr__()

from promptframe.exceptions import PromptNotFoundError

try:
    prompt = prompts.nonexistent_prompt
except PromptNotFoundError as e:
    print(e.pid)        # "nonexistent_prompt"
    print(e.available)  # ["summarize_text", "classify_topic"]

---

OutputParsingError

class OutputParsingError(Exception)

Raised when an LLM output cannot be parsed into the expected format (e.g. malformed JSON).

Constructor:

OutputParsingError(
    message: str = "Failed to parse the LLM response output.",
    response: str | None = None,
)

Attributes:

Attribute	Type	Description
message	str	Human-readable error description
response	str \| None	The raw LLM response string that failed to parse

Raised by: json_parser()

from promptframe.parsers import json_parser
from promptframe.exceptions import OutputParsingError

try:
    result = json_parser(llm_output)
except OutputParsingError as e:
    print(e.message)    # "Failed to parse the LLM response output."
    print(e.response)   # the raw string that couldn't be parsed

---

MissingContextKeyError (Deprecated)

class MissingContextKeyError(ValueError)

Raised when a required {placeholder} key is absent from the render context passed to a component or builder.

Constructor:

MissingContextKeyError(key: str)

Attributes:

Attribute	Type	Description
key	str	The missing placeholder key name

Note: Most render() methods use the @catch_keyerror decorator, which converts raw KeyError into a plain ValueError with a similar message. MissingContextKeyError is available for explicit use in custom components.

from promptframe.exceptions import MissingContextKeyError

class MyComponent(BasePromptComponent):
    def render(self, context=None):
        ctx = context or {}
        if "required_key" not in ctx:
            raise MissingContextKeyError("required_key")
        return ctx["required_key"]