Files
github-spec-kit/extensions/agent-context/scripts/python/update_agent_context.py
Marsel Safin 295eb221e3 feat(extensions): port update-agent-context to Python (#3387)
* feat(extensions): port update-agent-context to Python

Ports the agent-context extension updater to a single Python script,
per #3281 and the check-prerequisites PoC pattern from #3302. The bash
version already ran its core logic through embedded Python heredocs, so
the port lifts that logic into a standalone script. Parity tests run
bash and Python side by side and compare output and resulting
context-file bytes.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix(extensions): match bash case-insensitivity on MSYS, test unparseable config gate

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-07-08 07:46:29 -05:00

353 lines
13 KiB
Python

#!/usr/bin/env python3
"""Refresh the managed Spec Kit section in the coding agent's context file(s).
Python port of ``update-agent-context.sh`` / ``update-agent-context.ps1``.
Reads ``context_files`` or ``context_file``, plus ``context_markers.{start,end}``,
from the agent-context extension config:
.specify/extensions/agent-context/agent-context-config.yml
Usage: update_agent_context.py [plan_path]
When ``plan_path`` is omitted, the script derives it from
``.specify/feature.json`` (written by /speckit-specify). Falls back to the most
recently modified ``specs/*/plan.md`` only when feature.json is absent or its
plan does not exist yet.
"""
from __future__ import annotations
import json
import os
import re
import sys
from pathlib import Path
DEFAULT_START = "<!-- SPECKIT START -->"
DEFAULT_END = "<!-- SPECKIT END -->"
def _err(message: str) -> None:
print(message, file=sys.stderr)
def _get_str(obj: object, *keys: str) -> str:
node = obj
for key in keys:
if isinstance(node, dict) and key in node:
node = node[key]
else:
return ""
return node if isinstance(node, str) else ""
def _collect_context_files(data: dict, project_root: str) -> list[str]:
"""Resolve the managed context files from config, mirroring the bash logic."""
context_files: list[str] = []
seen: set[str] = set()
case_insensitive = sys.platform.startswith(("win32", "cygwin", "msys"))
def add(value: object) -> None:
if not isinstance(value, str):
return
candidate = value.strip()
if not candidate:
return
key = candidate.casefold() if case_insensitive else candidate
if key in seen:
return
context_files.append(candidate)
seen.add(key)
raw_files = data.get("context_files")
if isinstance(raw_files, list):
for value in raw_files:
add(value)
if not context_files:
add(_get_str(data, "context_file"))
if not context_files:
# Self-seed: when the config declares no target, derive one from the
# active integration recorded in init-options.json, mapped through the
# bundled agent-context-defaults.json file. Independent of the Specify
# CLI by design.
integration_key = ""
try:
with open(
f"{project_root}/.specify/init-options.json", "r", encoding="utf-8"
) as fh:
opts = json.load(fh)
if isinstance(opts, dict):
value = opts.get("integration") or opts.get("ai") or ""
integration_key = value if isinstance(value, str) else ""
except Exception:
integration_key = ""
if integration_key:
defaults_path = (
f"{project_root}/.specify/extensions/agent-context/"
"agent-context-defaults.json"
)
mapping = {}
try:
with open(defaults_path, "r", encoding="utf-8") as fh:
loaded = json.load(fh)
agents = loaded.get("agents", {}) if isinstance(loaded, dict) else {}
mapping = agents if isinstance(agents, dict) else {}
except Exception:
_err(
"agent-context: unable to read %s; cannot self-seed the context "
"file. Set context_file in the extension config." % defaults_path
)
mapping = {}
add(mapping.get(integration_key, "") or "")
if not context_files:
_err(
"agent-context: no default context file is known for integration "
"%s. Set context_file in the extension config to choose one."
% integration_key
)
return context_files
def _validate_context_file(project_root: str, context_file: str) -> str | None:
"""Return an error message when the path escapes the project root."""
if context_file.startswith("/") or re.match(r"^[A-Za-z]:", context_file):
return (
"agent-context: context files must be project-relative paths; "
f"got '{context_file}'."
)
if "\\" in context_file:
return (
"agent-context: context files must not contain backslash separators; "
f"got '{context_file}'."
)
if ".." in context_file.split("/"):
return (
"agent-context: context files must not contain '..' path segments; "
f"got '{context_file}'."
)
root = Path(project_root).resolve()
target = (root / context_file).resolve()
try:
target.relative_to(root)
except ValueError:
return (
"agent-context: context file path resolves outside the project root; "
f"got '{context_file}'."
)
return None
def _resolve_plan_path(project_root: str) -> str:
"""Derive the plan path: feature.json first, then the mtime fallback."""
plan_path = ""
feature_json = Path(project_root) / ".specify" / "feature.json"
if feature_json.is_file():
feature_dir = ""
try:
with open(feature_json, "r", encoding="utf-8") as fh:
data = json.load(fh)
value = data.get("feature_directory", "")
feature_dir = value if isinstance(value, str) else ""
except Exception:
feature_dir = ""
# Normalize backslashes (written by PS on Windows) before path ops.
feature_dir = feature_dir.replace("\\", "/").rstrip("/")
if feature_dir:
# feature_directory may be relative or absolute (absolute paths
# outside the project root are preserved as-is), including
# drive-qualified paths (C:/...) written by PowerShell on Windows.
if feature_dir.startswith("/") or re.match(r"^[A-Za-z]:/", feature_dir):
candidate = Path(feature_dir) / "plan.md"
else:
candidate = Path(project_root) / feature_dir / "plan.md"
if candidate.is_file():
# Resolve symlinks before comparing so paths like /var/… vs
# /private/var/… (macOS) are treated as equivalent.
root = Path(project_root).resolve()
resolved = candidate.resolve()
try:
plan_path = resolved.relative_to(root).as_posix()
except ValueError:
plan_path = resolved.as_posix()
if not plan_path:
root = Path(project_root).resolve()
plans = sorted(
(root / "specs").glob("*/plan.md"),
key=lambda p: p.stat().st_mtime,
reverse=True,
)
if plans:
try:
plan_path = plans[0].relative_to(root).as_posix()
except ValueError:
plan_path = ""
return plan_path
def _build_section(marker_start: str, marker_end: str, plan_path: str) -> str:
lines = [
marker_start,
"For additional context about technologies to be used, project structure,",
"shell commands, and other important information, read the current plan",
]
if plan_path:
lines.append(f"at {plan_path}")
lines.append(marker_end)
return "\n".join(lines) + "\n"
def ensure_mdc_frontmatter(content: str) -> str:
"""Ensure ``.mdc`` content has YAML frontmatter with ``alwaysApply: true``.
Cursor only auto-loads ``.mdc`` rule files that carry frontmatter with
``alwaysApply: true``. Prepend it when missing, or repair the value while
preserving any existing frontmatter comments/formatting.
"""
leading_ws = len(content) - len(content.lstrip())
leading = content[:leading_ws]
stripped = content[leading_ws:]
if not stripped.startswith("---"):
return "---\nalwaysApply: true\n---\n\n" + content
match = re.match(
r"^(---[ \t]*\r?\n)(.*?)(\r?\n---[ \t]*)(\r?\n|$)(.*)",
stripped,
re.DOTALL,
)
if not match:
return "---\nalwaysApply: true\n---\n\n" + content
opening, fm_text, closing, sep, rest = match.groups()
newline = "\r\n" if "\r\n" in opening else "\n"
if re.search(r"(?m)^[ \t]*alwaysApply[ \t]*:[ \t]*true[ \t]*(?:#.*)?$", fm_text):
return content
if re.search(r"(?m)^[ \t]*alwaysApply[ \t]*:", fm_text):
fm_text = re.sub(
r"(?m)^([ \t]*)alwaysApply[ \t]*:.*?([ \t]*(?:#.*)?)$",
r"\1alwaysApply: true\2",
fm_text,
count=1,
)
elif fm_text.strip():
fm_text = fm_text + newline + "alwaysApply: true"
else:
fm_text = "alwaysApply: true"
return f"{leading}{opening}{fm_text}{closing}{sep}{rest}"
def _upsert_section(
ctx_path: str, marker_start: str, marker_end: str, section: str
) -> None:
"""Insert or replace the managed section, then normalize and write."""
if os.path.exists(ctx_path):
with open(ctx_path, "r", encoding="utf-8-sig") as fh:
content = fh.read()
s = content.find(marker_start)
e = content.find(marker_end, s if s != -1 else 0)
if s != -1 and e != -1 and e > s:
end_of_marker = e + len(marker_end)
if end_of_marker < len(content) and content[end_of_marker] == "\r":
end_of_marker += 1
if end_of_marker < len(content) and content[end_of_marker] == "\n":
end_of_marker += 1
new_content = content[:s] + section + content[end_of_marker:]
elif s != -1:
new_content = content[:s] + section
elif e != -1:
end_of_marker = e + len(marker_end)
if end_of_marker < len(content) and content[end_of_marker] == "\r":
end_of_marker += 1
if end_of_marker < len(content) and content[end_of_marker] == "\n":
end_of_marker += 1
new_content = section + content[end_of_marker:]
else:
if content and not content.endswith("\n"):
content += "\n"
new_content = (content + "\n" + section) if content else section
else:
new_content = section
new_content = new_content.replace("\r\n", "\n").replace("\r", "\n")
if ctx_path.casefold().endswith(".mdc"):
new_content = ensure_mdc_frontmatter(new_content)
with open(ctx_path, "wb") as fh:
fh.write(new_content.encode("utf-8"))
def main(argv: list[str] | None = None) -> int:
args = sys.argv[1:] if argv is None else argv
project_root = os.getcwd()
ext_config = (
f"{project_root}/.specify/extensions/agent-context/agent-context-config.yml"
)
if not os.path.isfile(ext_config):
_err(f"agent-context: {ext_config} not found; nothing to do.")
return 0
try:
import yaml
except ImportError:
_err(
"agent-context: PyYAML is required to parse extension config but is "
"not available in the current Python environment.\n"
" To resolve: pip install pyyaml (or install it into the environment "
"used by python3).\n"
" Context file will not be updated until PyYAML is importable."
)
_err("agent-context: skipping update (see above for details).")
return 0
try:
with open(ext_config, "r", encoding="utf-8") as fh:
data = yaml.safe_load(fh)
except Exception as exc:
_err(
f"agent-context: unable to parse {ext_config} ({exc}); "
"cannot update context."
)
_err("agent-context: skipping update (see above for details).")
return 0
if not isinstance(data, dict):
data = {}
context_files = _collect_context_files(data, project_root)
if not context_files:
_err(
"agent-context: context_files/context_file not set in extension config; "
"nothing to do."
)
return 0
for context_file in context_files:
error = _validate_context_file(project_root, context_file)
if error:
_err(error)
return 1
marker_start = _get_str(data, "context_markers", "start") or DEFAULT_START
marker_end = _get_str(data, "context_markers", "end") or DEFAULT_END
plan_path = args[0] if args else ""
if not plan_path:
plan_path = _resolve_plan_path(project_root)
section = _build_section(marker_start, marker_end, plan_path)
for context_file in context_files:
ctx_path = os.path.join(project_root, context_file)
os.makedirs(os.path.dirname(ctx_path) or ".", exist_ok=True)
_upsert_section(ctx_path, marker_start, marker_end, section)
print(f"agent-context: updated {context_file}")
return 0
if __name__ == "__main__":
sys.exit(main())