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: Mistral Vibe Proposal: Upgrade Vibe hosts to Python 3.14 and rename subagent.* tools to agents.* Summary: Vibe v3.0.0 requires Python 3.14+, renames subagent.* to agents.*, and reserves agents/agent/collaboration for built-ins. Upgrade hosts, rewrite plugins, lock MCP with managed enable_mcp, and set enable_system_trust_store if a private CA will fail stricter RFC 5280 checks. Primary source: https://github.com/mistralai/mistral-vibe/releases/tag/v3.0.0

Why it matters

Vibe v3.0.0 breaks older Python runtimes and plugin contracts. It requires Python 3.14 or newer (previously 3.12). Built-in subagent tools are now agents.* instead of subagent.; sessions saved with the old names still resume, but new calls must use agents.. Plugins can no longer use the agents, agent, or collaboration tool namespaces, which are reserved for built-in agent tools. Admins can set enable_mcp in managed config to block all user-facing MCP operations (add, remove, toggle, login, logout, tool registration), including plugin-provided MCP servers. Outbound HTTPS now validates certificate chains with stricter RFC 5280 rules, so a private CA missing SKID/AKID or KeyUsage extensions may be rejected unless enable_system_trust_store is set or the CA is compliant. After that cutover, experimental_enable_model_catalog includes Mistral's curated models (config can still override their settings), and the Rust CLI /branch command forks the current conversation into a new resumable session.

Suggested actions

1. Install Python 3.14+ on every Vibe host, then install Mistral Vibe v3.0.0; do not attempt to run v3.0.0 on 3.12.
2. Search the workspace for subagent. and rename those tools to agents.; leave old session files as-is because they still resume.
3. Find plugins that register tools under agents, agent, or collaboration and move those tools off those reserved namespaces.
4. Add enable_mcp: false to managed config on locked-down machines so users cannot add, remove, toggle, login, logout, or register MCP servers, including plugin-provided servers.
5. Set enable_system_trust_store in Vibe config (or replace the CA) if outbound HTTPS uses a private CA missing SKID/AKID or KeyUsage; v3.0.0 may reject those certificates under stricter RFC 5280 checks.

Config surfaces this release may change

• MCP servers (high confidence) — check your repo before applying
• skills (high confidence) — check your repo before applying
• background and headless runs (high confidence) — check your repo before applying
• subagent definitions (high confidence) — check your repo before applying
• permission rules (high confidence) — check your repo before applying
• hooks — check your repo before applying
• settings files — 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/mistral-vibe-v3-0-0-upgrade-vibe-hosts-to-python-3-14-and-rename-subagen and mark Applied, Skipped, or Failed. Proposal id: fb274c64-f3f5-4600-a057-b712f3fe1d23

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.