feat: parse JSON additional_fields (#1)

[4erdenko]

PR Title

feat(jira): support `additional_fields` as dict or JSON string

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Summary

This patch lets the Jira FastMCP server accept additional_fields when it is passed either as a native dict or as a JSON‑encoded str. It removes validation failures that occurred when XML‑to‑JSON converters wrapped the object in quotes.

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Rationale

External clients (e.g. Anthropic Claude, Cursor) often emit tool calls in an XML‑like format. During XML → JSON‑RPC conversion, a nested JSON object is injected as a plain string:

"additional_fields": "{\"priority\": {\"id\": \"2\"}}"

Pydantic rejected this with dict_type. Accepting the string and parsing it server‑side solves the problem without breaking existing callers that already send a dict.

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Technical Details

• additional_fields type hint updated to dict[str, Any] | str | None.
• New branch parses a JSON string via json.loads; rejects invalid JSON or values that are not objects.
• Error messages clarified.

Code excerpt:

if additional_fields is None:
    extra_fields = {}
elif isinstance(additional_fields, dict):
    extra_fields = additional_fields
elif isinstance(additional_fields, str):
    extra_fields = json.loads(additional_fields)
    if not isinstance(extra_fields, dict):
        raise ValueError("parsed additional_fields is not an object")
else:
    raise ValueError("additional_fields must be a dict or JSON string")

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Tests

• test_create_issue_additional_fields_str_ok – JSON string accepted, issue created.
• test_create_issue_additional_fields_str_invalid – invalid JSON string returns clear ValueError.
• Existing tests for dict input remain green.

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Backward Compatibility

• No breaking changes.
• Calls that already send a dict behave exactly as before.
• Calls that send a non‑JSON string still fail fast with a clear error.

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Documentation

• Docstring for create_issue updated.
• If the public OpenAPI / tool schema is exported, change the field definition to:

"additional_fields": { "type": ["object", "string", "null"] }

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Related Issues

Fixes: #

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity for 14 days. It will be closed if no further activity occurs. Please leave a comment or remove the 'stale' label if you believe this PR is still relevant. Thank you for your contributions!

[4erdenko]

Up.

[makotarifa]

Works well!! Lets move this up 👍🏻

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity for 14 days. It will be closed if no further activity occurs. Please leave a comment or remove the 'stale' label if you believe this PR is still relevant. Thank you for your contributions!

[4erdenko]

@sooperset check this please

[mliq]

please yes - this fixes create_issue. Still issues with update_issue though. Would it be possible to include that fix? I will work on it and make a new PR crediting @4erdenko for this work.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity for 14 days. It will be closed if no further activity occurs. Please leave a comment or remove the 'stale' label if you believe this PR is still relevant. Thank you for your contributions!