Re: [RFC PATCH v2 07/10] .agents/skills: add qemu-mail-thread skill

[Chao Liu <chao.liu.zevorn@gmail.com>]

Hi Alex,
On Mon, May 11, 2026 at 06:04:56PM +0100, Alex Bennée wrote:
> Teach agents how to fetch and deal with archives of mail threads.
> 
> Just YOLO'ing the entire mail thread into an LLM context is quite
> expensive especially if reviewing a thread against your current tree
> state. This skill allows the agent to extract just the comments and
> tags saving tokens.
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> 
> ---
> v2
>   - rename to qemu-mail-thread
>   - add instructions on fetching threads via b4
>   - refactor the metadata handling in the script
>   - mention in AGENTS skill list
> ---
>  .agents/skills/qemu-mail-thread/SKILL.md      | 34 +++++++
>  .../scripts/qemu_mail_parser.py               | 98 +++++++++++++++++++
>  AGENTS.md                                     |  1 +
>  3 files changed, 133 insertions(+)
>  create mode 100644 .agents/skills/qemu-mail-thread/SKILL.md
>  create mode 100644 .agents/skills/qemu-mail-thread/scripts/qemu_mail_parser.py
> 
> diff --git a/.agents/skills/qemu-mail-thread/SKILL.md b/.agents/skills/qemu-mail-thread/SKILL.md
> new file mode 100644
> index 00000000000..58e7c833a27
> --- /dev/null
> +++ b/.agents/skills/qemu-mail-thread/SKILL.md
> @@ -0,0 +1,34 @@
> +# QEMU Mail Thread
> +
> +This skill helps you fetch and extract reviewer comments from QEMU mailing list threads. It can handle standard `mbox` files (e.g., from `b4 mbox`) or raw text dumps from the user.
> +
OpenAI Codex (v0.129.0-alpha.2) shows a warning when loading this skill:

⚠ Skipped loading 1 skill(s) due to invalid SKILL.md files.

⚠ /home/zevorn/qemu/.agents/skills/qemu-mail-thread/SKILL.md: missing YAML frontmatter delimited by ---

I suggest adding a check-skill script that validates skill format.

Thanks,
Chao
> +## How to fetch a mail thread
> +
> +If you have a Message-ID (e.g., from a patch series), use `b4` to fetch the entire thread:
> +
> +```bash
> +b4 mbox <message-id>
> +```
> +
> +This will typically save an `.mbx` file in your current directory.
> +
> +## How to parse comments
> +
> +Use the included Python script to extract feedback, filtering out quoted text and diffs.
> +
> +```bash
> +python .agents/skills/qemu-mail-thread/scripts/qemu_mail_parser.py <path_to_mail_thread_file>
> +```
> +
> +The script automatically detects whether the input is a standard mbox or a raw text dump.
> +
> +## Expected Output
> +The script generates `parsed_comments.txt` in the current working directory:
> +```
> +--- REPLY FROM Reviewer Name <email@example.com> ---
> +Subject: Re: [PATCH 01/10] ...
> +Comment text here...
> +============================================================
> +```
> +
> +Use this structured text to efficiently analyze the feedback and identify outstanding suggestions.
> diff --git a/.agents/skills/qemu-mail-thread/scripts/qemu_mail_parser.py b/.agents/skills/qemu-mail-thread/scripts/qemu_mail_parser.py
> new file mode 100644
> index 00000000000..fdaac57ac15
> --- /dev/null
> +++ b/.agents/skills/qemu-mail-thread/scripts/qemu_mail_parser.py
> @@ -0,0 +1,98 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +import sys
> +import os
> +import mailbox
> +
> +
> +def is_metadata_line(line):
> +    """Check if a line is metadata (quotes, diff, etc.)"""
> +    return (line.startswith(">") or
> +            line.startswith("---") or
> +            line.startswith("diff "))
> +
> +
> +def parse_raw_text(text, output_f):
> +    # Split by the separator used in lore.kernel.org / b4 dumps
> +    messages = text.split("----------------------------------------")
> +    for msg in messages:
> +        if not msg.strip(): continue
> +
> +        lines = msg.strip().split('\n')
> +        author = ""
> +        subject = ""
> +        body_start = 0
> +        for i, line in enumerate(lines):
> +            if line.startswith("From: "): author = line[6:]
> +            if line.startswith("Subject: "): subject = line[9:]
> +            if not line.strip() and body_start == 0:
> +                body_start = i + 1
> +                break
> +
> +        is_reply = subject and ("Re: " in subject or subject.startswith("Re:"))
> +
> +        if is_reply and author != "" and not author.startswith("qemu-devel"):
> +            output_f.write(f"--- REPLY FROM {author} ---\nSubject: {subject}\n")
> +
> +            for line in lines[body_start:]:
> +                if not is_metadata_line(line):
> +                    output_f.write(line + "\n")
> +            output_f.write("="*60 + "\n\n")
> +
> +
> +def parse_mbox(mbox_path, output_f):
> +    mbox = mailbox.mbox(mbox_path)
> +    for message in mbox:
> +        subject = message['subject']
> +        if subject and 'Re: ' in subject:
> +            author = message['from']
> +            output_f.write(f"--- REPLY FROM {author} ---\nSubject: {subject}\n")
> +
> +            payload = message.get_payload()
> +            body = ""
> +            if isinstance(payload, list):
> +                # Handle multipart
> +                for part in payload:
> +                    if part.get_content_type() == 'text/plain':
> +                        body = part.get_payload(decode=True).decode('utf-8', errors='ignore')
> +                        break
> +            else:
> +                body = message.get_payload(decode=True).decode('utf-8', errors='ignore')
> +
> +            # Simple heuristic to extract comments
> +            for line in body.split('\n'):
> +                if line.strip() and not is_metadata_line(line.strip()):
> +                    output_f.write(line + "\n")
> +            output_f.write("="*60 + "\n\n")
> +
> +
> +def main():
> +    if len(sys.argv) < 2:
> +        print("Usage: python qemu_mail_parser.py <mail_thread_file>")
> +        sys.exit(1)
> +
> +    input_file = sys.argv[1]
> +    output_file = "parsed_comments.txt"
> +
> +    if not os.path.exists(input_file):
> +        print(f"Error: File not found - {input_file}")
> +        sys.exit(1)
> +
> +    with open(output_file, "w", encoding="utf-8") as out_f:
> +        # Detect if it's an mbox or raw text
> +        with open(input_file, 'rb') as f:
> +            header = f.read(15)
> +            is_mbox = header.startswith(b'From mboxrd@z ')
> +
> +        if is_mbox:
> +            print(f"Parsing {input_file} as mbox...")
> +            parse_mbox(input_file, out_f)
> +        else:
> +            print(f"Parsing {input_file} as raw text dump...")
> +            with open(input_file, "r", encoding="utf-8", errors='ignore') as f:
> +                text = f.read()
> +            parse_raw_text(text, out_f)
> +
> +    print(f"Done. Extracted comments saved to {output_file}")
> +
> +if __name__ == "__main__":
> +    main()
> diff --git a/AGENTS.md b/AGENTS.md
> index fbbc3b65ed0..d99d3078378 100644
> --- a/AGENTS.md
> +++ b/AGENTS.md
> @@ -28,6 +28,7 @@ You should use the following specialized skills for common tasks:
>  - `qemu-build`: For configuring and building QEMU (including debug and sanitizer builds).
>  - `qemu-testing`: For finding, listing, and running individual tests (Unit, QTest, Functional, TCG).
>  - `qemu-code-reviewer`: For pulling and applying patch series from mailing lists.
> +- `qemu-mail-thread`: For analyzing and parsing mailing list threads.
>  
>  ## Source Code Layout (see `docs/devel/codebase.rst`)
>  - **`accel/`**: Hardware accelerators (KVM, TCG, HVF, Xen, etc.) and architecture-agnostic acceleration code.
> -- 
> 2.47.3
> 
>