# ctx7 / find-docs — DOTS library IDs & query playbook

**The `ctx7` CLI (or the `find-docs` skill) is the primary source of truth for every DOTS API, signature, and "current best practice."** Unity's Entities/Netcode/Physics packages change between versions and training-data recall is stale — resolve → query before writing DOTS code.

> The old context7 **MCP** verbs (`resolve-library-id` / `query-docs`) are **not in this environment's tool surface** — do not call them. Use the CLI / skill below.

## Flow (per the global `ctx7` rule)

1. **Resolve:** `npx ctx7@latest library "<official name>" "<your specific question>"` → pick the `/org/project` ID (prefer High reputation + high snippet count + the version closest to **installed**). Use proper punctuation in the name ("Netcode for Entities", "Unity Physics", "Entities Graphics").
2. **Fetch:** `npx ctx7@latest docs <libraryId> "<your specific question>"` — ask a *specific* question ("How do I read an `IInputComponentData` inside a predicted system filtered by `Simulate`?"), not a bare keyword.
3. Cross-check working patterns against the **ECS Samples** repo ID below.
4. Limit ≤3 `library` + ≤3 `docs` calls per question; reuse IDs across a session. On a quota error, suggest `npx ctx7@latest login` / `CONTEXT7_API_KEY` — don't silently fall back to memory.
5. The **`find-docs` skill** is an equivalent path (it wraps the same source) — either is fine.

## Two-source rule (do BOTH)

Pair every doc lookup with **`unity_reflect` on the installed type** for the real, version-pinned shape. Docs give the *current API*; reflection gives *what's actually compiled in this project* — they can disagree, and **reflection wins for the pinned engine version.** (A research-only lookup once produced a false-negative on a character-controller API that reflection would have caught.)

## Pin to the installed version

Read installed versions from `Packages/packages-lock.json` (or `manage_packages action=list`) before querying. This project runs the **unified Unity 6.5 line**: `com.unity.entities` / `com.unity.netcode` / `com.unity.physics` all **6.5.0** (the 6.x scheme tracks the Editor; it succeeded the old 1.x lines — Entities 6.4/6.5 is the direct successor to 1.4, Netcode 6.5 to the old ~1.12/1.13 line). **"1.13.2" is no longer an installable version** — treat any 1.x number as API-shape *lineage*, not a target string.

## Seed library IDs (verified live 2026-06-18 — re-resolve at code-time)

The doc sets on context7 currently **lag the package version** for most DOTS packages — only Entities has a `6_5` set. Pin the live top hit, knowing the package is 6.5.0; re-resolve when a newer set publishes.

| Package | Pin (live top hit) | Alt / notes |
|---|---|---|
| **Entities (DOTS)** | `/websites/unity3d_packages_com_unity_entities_6_5_manual` | version-matched; matches CLAUDE.md. Alt `…entities_1_4` has far more snippets (~10.8k) — useful for code patterns. |
| **Netcode for Entities** | `/websites/unity3d_packages_com_unity_netcode_1_10_api` | the live top hit (~4.3k snippets, High) — **no `netcode_6_5` set exists yet.** Package is 6.5.0; this is the closest published. Alt `…netcode_1_9`. |
| **Unity Physics** | `/websites/unity3d_packages_com_unity_physics_1_4` | live top hit (~4k snippets, High) — **no `physics_6_5` set yet.** Package is 6.5.0. |
| **Entities Graphics** | `/websites/unity3d_packages_com_unity_entities_graphics_1_4` | live top hit — **no `_graphics_6_5` set yet.** Package is 6.5.0. |
| **Official ECS Samples** | `/unity-technologies/entitycomponentsystemsamples` | working sample patterns (Entities/Netcode/Physics/Graphics). |
| **Burst / Collections / Mathematics** | resolve at runtime | `library "Unity Burst"` / `"Unity Collections"` / `"Unity Mathematics"`. |

> **Netcode for Entities ≠ Netcode for GameObjects.** Confirm it's `com.unity.netcode` (ECS), not `com.unity.netcode.gameobjects`.
> **CLAUDE.md's own pinned-ID note is itself partly stale** (it still says "we run 1.13.2") — lead with the installed 6.5.0 + the live re-resolve, and reconcile CLAUDE.md when you touch it.

## Query patterns that work

- "Entities: declare an `IJobEntity` writing through an `EntityCommandBuffer.ParallelWriter`, schedule with the right dependency."
- "Netcode for Entities: minimal `GhostAuthoringComponent` + `[GhostField]` for a predicted player-controlled ghost."
- "Netcode for Entities: read `IInputComponentData` in a system in `PredictedSimulationSystemGroup`, filtered by `Simulate`."
- "Entities: `Baker<T>` use of `GetEntity` with `TransformUsageFlags` + `DependsOn`."
- "Entities: `IEnableableComponent` vs add/remove tag — API + when each is cheaper."

## When NOT to use ctx7

- Genre/design precedent ("how do other games pace waves") → `WebSearch`/`WebFetch`. **Never use web for a DOTS API shape.**
- Pure C#/algorithm questions unrelated to a library → reason directly.
- The project's own conventions/design → `CLAUDE.md` + the vault.