Captions for AI agents
Captions provides the Mirage API for generating AI video and speech and adding styled captions on top, for teams producing short-form video content. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.
What agents do in Captions.
Add captions to a video
Add styled captions to a video using a chosen template, ready for social posting.
Generate an AI voiceover
Generate a speech track from a script before pairing it with a video.
Check a video job's status
Check whether a queued video generation job has finished before downloading it.
8 Captions actions, graded by risk.
Every Captions action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.
read
5Look things up. Allowed by default.
- captions.list_videosList Videos
- captions.get_video_statusGet Video Status
- captions.get_caption_templateGet Caption Template
- captions.list_caption_templatesList Caption Templates
- captions.download_videoDownload Video
write
3Create and change things. Allow, or ask the user first.
- captions.add_captionsAdd Captions
- captions.generate_videoGenerate Video
- captions.generate_speechGenerate Speech
destructive
0Delete, cancel or archive. Ask first, or deny outright.
- No destructive actions.
Captions in three steps.
- 01Your users connect CaptionsThey add their Captions api key on Arc0 Connect, under your brand. It goes straight into the vault.
- 02You set the rulesReads run, and writes like “add Captions” can wait for the user to approve.
- 03Any agent can actYour agent calls Captions through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
await arc0.policies.set('captions', { read: 'allow', write: 'ask', // add_captions destructive: 'deny', }) # Claude Code: the same connection, one URL $ claude mcp add --transport http arc0 \ https://mcp.arc0.ai/u/u_8f2
How Captions connects.
Users add their Captions api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.
The same Captions connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →
- AUTH
- API key
- CREDENTIALS
- Per-tenant encrypted vault
- MODEL SEES
- Results only, never credentials
- AUDIT LOG
- Every call, on every plan
Use Captions from any agent.
ClaudeChatGPTCursor
Codex
VS CodeOpenAI Agents SDKClaude Agent SDK
Vercel AI SDK
Mastra
LangGraph
Captions and Arc0, answered.
Can I use Captions with Claude, ChatGPT or Cursor?
Yes. Connect Captions to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the Captions actions you allow.
How do users connect Captions?
Users add their Captions api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.
Which Captions actions can my agent take?
8 in total: 5 read, 3 write and 0 destructive, such as “add Captions”. Your policies decide which of them each agent may call.
Can I make my agent read-only in Captions?
Yes. Allow read actions and deny writes in the Captions policy. Your agent can still look things up, and any write it attempts is blocked and logged.
Can my own backend call Captions too?
Yes. The same Captions connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.
Plug Captions into your agent.
Your users connect Captions once, under your brand. Your agent gets 8 actions behind your policies, with every call on the record.
Free to build · MCP + REST · Audit log on every plan