DevAgentRadar → Repo Harness Rule Patch

Goal: update our repository's permanent harness instructions based on this release.

Update the file that tool actually reads. Do not dump everything into one file.

• Claude Code → CLAUDE.md plus .claude/ (skills, hooks, settings, agents, commands). It does not read AGENTS.md natively; start CLAUDE.md with @AGENTS.md.
• Codex, Copilot, Cursor, Factory Droid, Grok Build, Roo Code, Goose, OpenCode, Amp, Zed, Aider → AGENTS.md.
• Gemini CLI / Antigravity → GEMINI.md. AGENTS.md only if context.fileName is set.
• Cursor glob-scoped rules → .cursor/rules/*.mdc (plain .md is ignored), not a second constitution.
• Codex MCP → .codex/config.toml, not .mcp.json.
• Copilot extra instructions → .github/copilot-instructions.md; custom agents → .github/agents/.
• Windsurf → .windsurf/rules (do not assume AGENTS.md).
• Cline → .clinerules.
• Procedures → a skill (SKILL.md). Enforcement the model must not skip → a hook. Isolated roles → subagents.
• Do not fork the same rule into three tool files.

Context

Assistant: GitHub Copilot CLI Proposal: Add path-specific Copilot CLI instructions under .github/instructions Summary: Copilot CLI v1.0.100 auto-applies instruction files from repo-root .github/instructions when the agent reads or edits a matching file. Add those files, then use --trust-folder and --disable-client-telemetry on one-off -p/stdin runs so conventions and session trust travel with the repo. Primary source: https://github.com/github/copilot-cli/releases/tag/v1.0.100

Why it matters

v1.0.100 automatically applies path-specific instruction files from the repository root .github/instructions when the agent reads or edits a matching file. Commit those files so file-type conventions apply without repeating them in prompts.

Pair that with the new one-off session flags. --trust-folder trusts the working tree for prompt-mode (-p) and piped-stdin runs only. --disable-client-telemetry stops client telemetry uploads from the CLI—add both to aliases and CI.

Sandbox behavior changed in the same release: /sandbox can keep sandboxing on for the current session without enabling it globally; host-rule traffic honors HTTPS_PROXY and HTTP_PROXY when no sandbox proxy is set; local network access is allowed by default. Custom agents that declare the documented search, web, or todo aliases, or name github-mcp-server/web_search, now receive those tools. Verified Skills and plugins install from GitHub links with copilot plugin install "ghapp://air/install?..."

Suggested actions

1. Create path-specific instruction files in the repository root .github/instructions for every file type this repo regularly edits. Copilot CLI v1.0.100 applies them automatically when the agent reads or edits a matching file; do not store them outside that directory.
2. Run one-off Copilot CLI prompts as: copilot --trust-folder --disable-client-telemetry -p "<your prompt>" (same flags for piped stdin) so the folder is trusted for that session only and the CLI does not upload client telemetry.
3. In Copilot CLI, open /sandbox and keep sandboxing enabled for the current session without enabling it globally. Expect localhost and private-network access by default; host-rule traffic uses HTTPS_PROXY and HTTP_PROXY when no sandbox proxy is configured.
4. Install a verified Skill or plugin from its GitHub install link with: copilot plugin install "ghapp://air/install?<params>"
5. On custom agents, declare the documented search, web, or todo tool aliases, or name github-mcp-server/web_search, so Copilot CLI v1.0.100 injects the matching tools.

Config surfaces this release may change

• sandbox settings — check your repo before applying
• MCP servers — check your repo before applying
• subagent definitions — check your repo before applying
• permission rules — check your repo before applying
• skills — check your repo before applying

After you finish

Do not report this as applied to DevAgentRadar. You cannot write the visitor's loop.

Tell the human: open https://devagentradar.com/proposals/github-copilot-cli-v1-0-100-add-path-specific-copilot-cli-instructions-u and mark Applied, Skipped, or Failed. Proposal id: 556827de-7b4e-4990-b588-20e1a6d0a115

Instructions:

1. Read the existing context files and settings for the tools in this repo.
2. Draft an explicit Git diff. Update ONLY agent harness rules or tool configuration.
3. Call out deprecated flags, obsolete habits, or changed permission boundaries.
4. Do not touch application logic.

Start with the proposed diff and say which layer and which tool's file it belongs in.