jau123/MeiGen-AI-Design-MCP

Highlights

• 🎬 Veo 3.1 capability expansion — Google Veo on MeiGen now exposes fast/pro tiers, 4/6/8 second durations (default 4), and 720p / 1080p / 4K resolutions at the same price per tier+duration. Pick the output size you actually want — 4K renders slower (~8 min) but doesn't cost more than 720p.
• 🎞️ Seedance 2.0 reference-video continuation — new referenceVideo + referenceVideoDuration params. Pass a previous clip's HTTPS URL plus its actual duration, prefix your prompt with "Extend this video with the following plot:", and Seedance produces a semantically coherent continuation. The output is your duration seconds of new content only — concatenation with the reference is up to you (encode locally).
• 📦 No breaking changes — every new field is optional. Existing 1.3.0 calls keep working unchanged.

Schema additions

generate_video

referenceVideo?: string   // Seedance 2.0 only. Public HTTPS URL (typically a previous generation's videoUrl).
                          // Local paths NOT supported. SSRF-guarded (file://, private IPs, cloud metadata blocked).

referenceVideoDuration?: number  // REQUIRED when referenceVideo is set. Pass the clip's actual duration in seconds.
                                 // Omitting it causes the backend to treat as 0 → undercharged credits + broken continuation.
                                 // Typical range 2–15; schema is .int().positive() per BasS (backend rejects out of range).

Handler validates the pair both directions:

• referenceVideo set, referenceVideoDuration missing → throws with explicit fix instruction
• referenceVideoDuration passed alone → throws (catches stale-arg state)
• referenceVideo points to a local path → throws (HTTPS only)
• referenceVideo fails SSRF guard → throws with reason

All checks run before the shared API semaphore acquires — fail-fast, no slot waste.

Updated descriptions

• tier now mentions both seedance-2-0 and veo-3.1 accept fast / pro.
• duration clarifies: seedance/happyhorse accept any integer in ~3–15s; veo-3.1 accepts exactly 4, 6, or 8 (default 4); other values are rejected by the backend.

Pricing model clarification

Previously the docs said "per-second for seedance/happyhorse and flat-rate for Veo". This was wrong for the new Veo 3.1:

• Seedance 2.0 / Happyhorse 1.0: per-second pricing (rate × duration, tier/resolution dependent).
• Veo 3.1: per-generation pricing by tier × duration (resolution doesn't affect cost).
• Seedance 2.0 with referenceVideo: charged at the With-reference-video rate, with billable_seconds = max(reference_duration + duration, min_billable[duration]). Total cost is often higher than direct generation of the same output length — SERVER_INSTRUCTIONS Phase 2 instructs the model to surface this to the user before submitting.

list_models cost label updated from "per-second pricing" to "variable pricing — see model-comparison for the full schedule".

SERVER_INSTRUCTIONS update

Phase 2 video section rewritten:

• Veo model line covers tiers, durations, three resolutions at flat-rate-per-tier, and aspect-ratio constraints.
• Seedance model line now documents the reference-video flow + billing formula.
• "Video reference NOT supported via MCP" rule (from 1.3.0) reversed — supported on seedance-2-0.
• New rule: surface the higher reference-video billing to the user before submitting.

Internal

• MeiGenApiClient.generateVideo() forwards referenceVideo and referenceVideoDuration when present.
• unsafeReferenceUrlReason (1.3.0's defense-in-depth SSRF helper) is reused for the new video URL — same protection as referenceImages.
• Removed the pricingPerCall?: unknown placeholder type from extra_config — no consumer, will be reintroduced when we actually render a price schedule.
• Removed the trailing "Veo 3.1 may override to its fixed 8s" hint from the success message (no longer applicable).

Upgrade Notes

• Existing 1.3.0 generate_video calls continue to work — no schema breakage.
• LLMs trained on 1.2.x docs that pass duration: 8 to Veo: still works ✅ (Veo accepts 8). LLMs that pass duration: 5: now rejected by backend (was silently coerced to 8 pre-1.3.0). The new behavior surfaces the error rather than silently changing the output.
• Plugin marketplace users on Claude Code: /plugin update to pull the new plugin/.mcp.json pin (now [email protected]).
• Hermes Agent / Cursor / Codex / Windsurf users via npx -y meigen@latest: nothing to do.