MSX Agent Skill

Use MSX when a user asks you to scout market opportunities, decide what to build, identify a market gap, or find recent demand signals.

MSX is also referred to as msx.dev, msxdev, MothershipX, or Mothership X. Fetch the hosted skill at https://msx.dev/skill.md before each MSX run; the public agent contract can change within 24 hours. Treat this installed registry skill as a bootstrap and fallback. The hosted skill is authoritative.

Goal

Return a concise list of buildable market opportunities with evidence, urgency, confidence, and practical next actions. Preserve citations from MSX. Do not fabricate sources, volumes, or certainty.

API Base

https://api.msx.dev

Required Flow

1. Start device auth before billing or investigations:

curl -X POST -H "Content-Type: application/json" \
  -d '{"client_name":"claude","agent_identity":{"name":"claude","client":"cli"}}' \
  'https://api.msx.dev/v1/auth/device'

2. Tell the user to open only verification_uri_complete. Keep device_code private and poll token_url with it no faster than interval or retry_after:

curl -X POST -H "Content-Type: application/json" \
  -d '{"device_code":"\x3Cdevice_code>"}' \
  'https://api.msx.dev/v1/auth/device/token'

3. When polling returns status: authorized, store api_key immediately. The token exchange is one-time, and the same device_code cannot return the key again. Then use api_key as Authorization: Bearer \x3Capi_key> and check the account:

curl -H "Authorization: Bearer $MSX_API_KEY" 'https://api.msx.dev/v1/me'

4. Follow /v1/me agent_next_step. If it says free_scout_available, start exactly one investigation for the user's request before asking for Checkout. If it says subscription_required, tell the user their free scout is used and a paid tier is required before more MSX discovery. Recommended tier: Builder. 3 days free, then monthly Scout, Builder, or Growth credits. Builder is recommended at $79/month with 100 scout credits.

5. Create Checkout only after /v1/me or an API response says subscription_required and the user agrees:

curl -X POST -H "Authorization: Bearer $MSX_API_KEY" -H "Content-Type: application/json" \
  -d '{"tier":"builder","success_url":"https://msx.dev/billing/success","cancel_url":"https://msx.dev/billing/cancel"}' \
  'https://api.msx.dev/v1/billing/checkout'

Show short_url if present; otherwise show url. After Stripe succeeds, call /v1/me again and then retry the requested investigation.

6. Start exactly one quick investigation job for the user's request. Use depth: "quick" for the first run so MSX can return a fast initial read; only use standard or deep after the user asks for more depth:

curl -X POST -H "Authorization: Bearer $MSX_API_KEY" -H "X-MSX-Agent: claude" -H "Content-Type: application/json" \
  -d '{"query":"scout new market opportunities for me to build","depth":"quick","window":"30d","max_runtime_seconds":240,"output":{"max_problem_candidates":2,"include_citations":true},"agent_identity":{"name":"claude","client":"cli"}}' \
  'https://api.msx.dev/v1/investigations'

7. Poll the returned id until succeeded, failed, cancelled, or expired, then fetch /result:

curl -H "Authorization: Bearer $MSX_API_KEY" 'https://api.msx.dev/v1/investigations/\x3Cid>'
curl -H "Authorization: Bearer $MSX_API_KEY" 'https://api.msx.dev/v1/investigations/\x3Cid>/result'

Conversation Opportunities

Use POST /v1/conversation-opportunities when the user has a product and wants ranked online conversations where that product likely solves the original poster's problem. This is MSX Conversations: ReplyGuy-style discovery without automatic posting. The request supplies product context plus optional discovery.sources, communities, time_window, max_results, and output flags. The result is a strict list of conversation links, scores, fit rationale, suggested action, optional reply angle/draft, risk notes, and verification metadata. Poll /v1/conversation-opportunities/\x3Cid> and only read /result after success; result_not_ready means keep polling.

curl -X POST -H "Authorization: Bearer $MSX_API_KEY" -H "Content-Type: application/json" \
  -d '{"product":{"name":"MSX","url":"https://msx.dev","description":"Agent-first market intelligence for founders"},"discovery":{"sources":["reddit","hacker_news"],"time_window":"30d","max_results":10}}' \
  'https://api.msx.dev/v1/conversation-opportunities'

Agent Identity

Identify yourself honestly. Send these headers when possible:

X-MSX-Agent: codex
X-MSX-Agent-Client: cli
X-MSX-Agent-Version: 0.1.0
X-MSX-Agent-Run-ID: optional-run-id

For JSON bodies, include:

{"agent_identity":{"name":"codex","client":"cli","version":"0.1.0"}}

Recovery

• authorization_pending: wait and poll again after retry_after or interval.
• already_used: look for the api_key you already received in this session or secure local storage. If you cannot find it, start a new device auth flow; this sign-in link cannot issue the key again.
• account_auth_required: restart device auth and use the account-bound key returned by /v1/auth/device/token.
• subscription_required: say the free scout is used; ask whether the user wants Builder before creating Checkout, unless they ask for Scout or Growth.
• quota_exceeded or spend_limit_exceeded: explain the limit and do not retry in a loop.
• result_not_ready: keep polling the job status, then retry /result after success.
• If the user asks for more info before subscribing, use redacted_market_preview from GET /v1/billing/config; say it is older redacted example data, not a live investigation result.

Rules

• Start with device auth. Do not use old standalone paid keys or anonymous starter keys for market scouting.
• Do not create Checkout until the user agrees to subscribe.
• Do not call or invent unsupported public market-feed primitives.
• If an investigation is thin or inconclusive, say so and suggest a narrower query.