Cross-Editor Agent Setup

Not using Claude Code? The Claude Code plugin wires Lien's nudges in via hooks — deterministic, fires on every matching tool call. Most other agentic editors don't have an equivalent hook integration from Lien yet, but nearly all of them read a plain instruction file already: a single AGENTS.md at your repo root is read natively by Codex CLI, Cursor, Windsurf (Cascade), GitHub Copilot, Devin, and Amp. .github/copilot-instructions.md covers every Copilot surface the same way. Two files, five-plus tools raised off the rules-file floor.

Be honest about what this buys you

Lien's own Claude Code plugin page makes the case for hooks over rules-file text: a hook fires deterministically regardless of what's still in the model's context, while a written instruction is a standing suggestion competing for attention across a long session, and a capable agent can still skip it under context pressure or by taking a shortcut (e.g. reading a file via a shell command instead of its native Read tool, which wouldn't trigger a hook either way even where hooks exist). That's design rationale, not a citation — so here's what's actually measured: a pre-registered A/B injecting Lien's real complexity warning into a coding-agent prompt (N=8/condition) found the agent crossed its complexity threshold in 8/8 control trials versus 3/8 with the warning present — every trial that avoided crossing did so by extracting a helper function, matching the warning's own wording, "prefer extraction" (see docs/development/nudge-behavioral-ab.md). That study shows an injected signal changes behavior versus no signal at all — it isn't a head-to-head of rules-file prose against a hook carrying the identical instruction, and no such head-to-head is checked into this repo. So: the blocks below are genuinely useful, strictly better than nothing, and for the editors on this page they're currently the only nudge Lien can offer — but treat compliance as best-effort, not guaranteed, and don't read more evidence into that claim than exists above. If your editor gets a real hook port later (see the roadmap below), that will raise the floor further.

AGENTS.md — the universal block

Drop this at your repo root (or append it to an existing AGENTS.md). It's plain markdown — copy it as-is:

## Lien: query before you touch code

This repo is indexed by [Lien](https://lien.dev) (MCP). Before editing any
file, call `get_files_context` — check `testAssociations`, `imports`, and any
`complexityHeadroomWarning` in the response before you touch it (batch with
`filepaths: [...]` for multi-file edits). Before renaming, removing, or
changing the signature of an exported symbol, call `get_dependents` — a
`riskLevel` of `high` or `critical` means list the affected dependents before
proceeding. Before committing, run `lien delta`; treat any new
complexity-threshold crossing it reports as must-fix, not advisory.

That's the whole mandate — kept short deliberately. Every extra sentence competes with the rest of your rules file for the same limited attention.

GitHub Copilot — .github/copilot-instructions.md

This file is GA today and needs no opt-in: Copilot includes it automatically in every chat request across VS Code, JetBrains, github.com, and Copilot CLI — the single highest-reach, lowest-effort artifact of the two on this page. Same content, same reasoning:

## Lien: query before you touch code

This repo is indexed by [Lien](https://lien.dev) (MCP). Before editing any
file, call `get_files_context` — check `testAssociations`, `imports`, and any
`complexityHeadroomWarning` in the response before you touch it (batch with
`filepaths: [...]` for multi-file edits). Before renaming, removing, or
changing the signature of an exported symbol, call `get_dependents` — a
`riskLevel` of `high` or `critical` means list the affected dependents before
proceeding. Before committing, run `lien delta`; treat any new
complexity-threshold crossing it reports as must-fix, not advisory.

If you already have an AGENTS.md, Copilot reads that natively too — but .github/copilot-instructions.md is the file Copilot's docs commit to including in every chat request, so committing both removes any ambiguity about which surfaces pick which file up.

Windsurf / Cascade: one real caveat

Cascade reads AGENTS.md dynamically as it navigates your repo, so the block above reaches it too — no extra file needed. The caveat, verified against Cascade's own hook docs: Cascade's hook system (pre_write_code, pre_read_code, and others) can log tool calls and hard-block them outright, but hook output is never injected back into the model's context. That means for Windsurf specifically, the AGENTS.md block above is the entire nudge — there's no hook backstop underneath it the way there is for Claude Code. Treat it as best-effort here more than anywhere else on this page.

Codex CLI: already reading AGENTS.md today

Codex CLI auto-reads AGENTS.md, walking from its home directory down through the project tree and concatenating what it finds — nothing to configure. Codex's own hook system went stable in v0.124.0 (April 23, 2026), with an event schema close enough to Claude Code's own PostToolUse/PreToolUse pair that a real port of Lien's hooks is plausible future work — not yet shipped. Until then, the AGENTS.md block above is Codex's nudge floor.

Cursor

Cursor also reads AGENTS.md natively, so the universal block covers it without any extra setup. Cursor's hooks (introduced in Cursor 1.7, October 2025, GA as of mid-2026) and its .cursor/rules/*.mdc targeting system are both richer than a flat AGENTS.md — tracked as follow-up work, not shipped today.

Roadmap: what's tracked next

This page ships the rules-file floor (step 1 of Lien's cross-editor plan). Hook ports are follow-up work, in priority order:

Environment	Ships today	Tracked next
Codex CLI	Reads AGENTS.md natively	Hook port (stable API since v0.124.0)
Cursor	Reads AGENTS.md natively	Hook port to .cursor/hooks.json (hooks GA as of mid-2026)
GitHub Copilot	.github/copilot-instructions.md (GA)	Hooks — stable in Copilot CLI, Preview in VS Code since its Feb 2026 release; worth a beta label or a wait for GA
Windsurf/Cascade	Reads AGENTS.md natively	Optional pre_write_code hard-block script for the delta gate — additive, but can't carry the read-annotation nudge regardless (architecture limit, not effort)
Aider	Nothing yet	Not planned — no native MCP support as of mid-2026; a --lint-cmd wrapper around lien delta is the only workaround worth a doc note

Related pages

• Claude Code Plugin — the hook-driven version of this same mandate, for Claude Code.
• MCP Tools — parameters and response shapes for get_files_context, get_dependents, and the rest.
• Quick Start — per-editor lien init setup if you haven't configured Lien's MCP server yet.