Project-M/.claude/skills/dots-dev/references/context7-libraries.md

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.