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7d2f1f9671
Addresses #541: - Server now auto-deserializes JSON string args (list, dict, BaseModel) for prompts. This simplifies server-side prompt logic by reducing boilerplate `json.loads()` calls. - Docs updated to clarify `list_resource_templates` usage for templatized resources. - Docs updated to require client-side `json.dumps()` for complex `get_prompt` arguments, resolving the original Pydantic error. - Adds a new example (`examples/dynamic_story_prompt/`) demonstrating the server-side deserialization benefit and correct client-side serialization. Closes #541. --- Notes for Reviewers: - **Server-Side Auto-Deserialization:** This change introduces a "magic" `json.loads()` in `Prompt.render`. This is an intentional DX improvement. It only triggers for `str` inputs targeting `list`, `dict`, or `BaseModel` type hints. If `json.loads()` fails (e.g., malformed JSON), the original string is passed to Pydantic's `validate_call`, ensuring robust error handling. This avoids boilerplate in user prompt functions. - **Client `get_prompt()` Return Value:** The `examples/dynamic_story_prompt/story_client.py` parses the result of `client.get_prompt()` by iterating and looking for a `('messages', ...)` tuple. This reflects the observed behavior of the current `client.get_prompt()`. This commit does *not* change `client.get_prompt()`'s return behavior; the example merely adapts to it. A separate discussion might be warranted for potentially simplifying `client.get_prompt()`'s return signature in the future.
96 lines
3.4 KiB
Python
96 lines
3.4 KiB
Python
import asyncio
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import json
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from fastmcp import Client
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SERVER_SCRIPT_PATH = __file__.replace("client", "server")
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async def main():
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print(f"Attempting to connect to server script: {SERVER_SCRIPT_PATH}\n")
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client = Client(SERVER_SCRIPT_PATH)
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async with client:
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print("Successfully connected to server!")
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# 1. Define the complex data for the prompt
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character_data = {
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"name": "Elara",
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"archetype": "Reluctant Oracle",
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"quirky_trait": "habit of humming ancient, forgotten tunes when nervous",
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}
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objects_data = [
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"a tarnished silver locket that refuses to open",
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"a smooth, obsidian sphere that whispers secrets in the dark",
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"a single, petrified rose that blooms only in moonlight",
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]
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laws_data = {
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"time": "flows like molasses uphill on Tuesdays",
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"shadows": "have a mind of their own and occasionally steal small, shiny objects",
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"laughter": "can briefly mend broken things",
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}
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# 2. Prepare arguments for the client, serializing complex types to JSON strings
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prompt_args = {
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# 'character_details' expects a Character Pydantic model
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"character_details": json.dumps(character_data),
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# 'mysterious_objects' expects a list[str]
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"mysterious_objects": json.dumps(objects_data),
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# 'world_laws' expects a dict[str, str]
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"world_laws": json.dumps(laws_data),
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}
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print("--- Sending to server: ---")
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for key, value in prompt_args.items():
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print(f" {key}: {value}")
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print("--------------------------\n")
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try:
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# 3. Call the prompt
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results_iterable = await client.get_prompt(
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"generate_dynamic_story_prompt", arguments=prompt_args
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)
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print("--- Generated Story Prompt from Server: ---")
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# The client.get_prompt() seems to return an iterable of (key, value) pairs
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# from the GetPromptResult model. We need to find the 'messages' key.
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prompt_messages_list = None
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if results_iterable:
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for key, value in results_iterable:
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if key == "messages":
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prompt_messages_list = value
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break # Found the messages list
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if prompt_messages_list:
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for message in (
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prompt_messages_list
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): # This should be a list of PromptMessage objects
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if (
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hasattr(message, "content")
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and hasattr(message.content, "text")
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and message.content.text is not None
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):
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print(message.content.text)
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else:
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print(
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f"(Received message with unexpected content structure: {message!r})"
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)
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else:
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print(
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"(Could not find 'messages' in the prompt result or result was empty)"
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)
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print("-----------------------------------------")
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except Exception as e:
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print(f"Error calling prompt: {e}")
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import traceback
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traceback.print_exc()
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if __name__ == "__main__":
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asyncio.run(main())
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