fix: derive plan path from feature.json in update-agent-context

[amirreza225]

Summary

• update-agent-context.sh and update-agent-context.ps1 now prefer .specify/feature.json (written by /speckit-specify) over the mtime heuristic when no explicit plan_path argument is given
• Falls back to most-recently-modified specs/*/plan.md only when feature.json is absent or the derived plan.md does not exist yet (e.g. /speckit-plan hasn't run yet)
• Handles absolute feature_directory values in both scripts, normalizing to project-relative paths for the context file output
• PowerShell implementation is PS 5.1-compatible: nested Join-Path, IsPathRooted guard (Unix Join-Path does not treat absolute ChildPaths as "wins"), and manual prefix-strip instead of GetRelativePath

Fixes #3067

AI disclosure

This PR was written with AI assistance (Claude Code). All changes were reviewed, tested, and understood by me before submission.

Manual test results

Agent: Claude Code | OS/Shell: macOS/zsh

Command tested	Notes
/speckit.specify → /speckit.plan	CLAUDE.md references the correct active feature's plan.md
Multi-spec repo with stale plan touched after specify	CLAUDE.md still points to active feature, not the stale one

Test plan

• uv run pytest tests/extensions/test_update_agent_context_feature_json.py — 4 new bash tests pass (2 PS skipped, no pwsh on CI)
• uv run pytest tests/test_agent_config_consistency.py tests/extensions/test_extension_agent_context.py — all 62 existing tests pass

[Copilot]

Pull request overview

This PR updates the agent-context extension’s context refresh scripts so that, when no explicit plan_path argument is provided, they derive the active plan.md from .specify/feature.json (written by /speckit-specify) and only fall back to the “most recently modified specs/*/plan.md” heuristic when that source is unavailable or not yet present. It also adds tests to validate the new feature.json-first behavior.

Changes:

• Bash: Prefer .specify/feature.json to resolve the active plan.md, with mtime fallback retained.
• PowerShell: Implement the same “feature.json-first, mtime-second” selection logic and normalize feature paths.
• Tests: Add coverage ensuring feature.json overrides the mtime heuristic (bash + PowerShell where available).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
extensions/agent-context/scripts/bash/update-agent-context.sh	Uses .specify/feature.json to select the active plan when plan_path isn’t provided; retains mtime fallback.
extensions/agent-context/scripts/powershell/update-agent-context.ps1	Mirrors bash behavior in PowerShell, including absolute-path normalization and mtime fallback.
tests/extensions/test_update_agent_context_feature_json.py	Adds tests validating feature.json-first selection and stale-plan avoidance.

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[mnriem]

Please address Copilot feedback

[amirreza225]

All three Copilot comments have been addressed in commit 80600a2:

1. GetRelativePath not available in PS 5.1 — replaced with a manual prefix-strip using StartsWith/Substring in both the feature.json path and the mtime fallback sections of update-agent-context.ps1.

2. open() missing explicit encoding — added encoding="utf-8" to the json.load(open(...)) call in the feature.json snippet in update-agent-context.sh.

3. No tests for absolute feature_directory — added two new bash tests:

   • test_bash_absolute_feature_dir_under_project_root: absolute path under $PROJECT_ROOT → context file contains project-relative path (not machine-specific absolute)
   • test_bash_absolute_feature_dir_outside_project_root: absolute path outside $PROJECT_ROOT → absolute path preserved as-is

All 70 tests pass locally.

[amirreza225]

Please address Copilot feedback

Done

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[Copilot]

Copilot's findings

• Files reviewed: 3/3 changed files
• Comments generated: 2

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.