Agent skill

neynar

Interact with Farcaster via Neynar API. Use when the user wants to read Farcaster feeds, look up users, post casts, search content, or interact with the Farcaster social protocol. Requires NEYNAR_API_KEY.

View SKILL.md on GitHub Repository
Stars 163
Forks 31

Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/neynar

Metadata

Additional technical details for this skill

thinkfleetbot 
{
    "emoji": "\ud83d\udfea",
    "homepage": "https://neynar.com",
    "requires": {
        "bins": [
            "curl",
            "jq"
        ]
    }
}

SKILL.md

Neynar (Farcaster API)

Interact with the Farcaster decentralized social protocol via Neynar's API.

Quick Start

Setup

  1. Get an API key from dev.neynar.com
  2. Create config:
bash
mkdir -p ~/.thinkfleet/skills/neynar
cat > ~/.thinkfleet/skills/neynar/config.json << 'EOF'
{
  "apiKey": "YOUR_NEYNAR_API_KEY",
  "signerUuid": "YOUR_SIGNER_UUID"
}
EOF

Note: signerUuid is only required for posting casts. Get one via Neynar's signer management.

Verify Setup

bash
scripts/neynar.sh user dwr.eth

Core Concepts

  • FID — Farcaster ID, a permanent numeric identifier for each user
  • Cast — A post on Farcaster (like a tweet)
  • Channel — Topic-based feeds (like subreddits)
  • Frame — Interactive mini-apps embedded in casts

Usage

User Lookup

bash
# By username
scripts/neynar.sh user vitalik.eth

# By FID
scripts/neynar.sh user --fid 5650

# Multiple users
scripts/neynar.sh users dwr.eth,v,jessepollak

Read Feed

bash
# User's casts
scripts/neynar.sh feed --user dwr.eth

# Channel feed
scripts/neynar.sh feed --channel base

# Trending feed
scripts/neynar.sh feed --trending

# Following feed (requires signer)
scripts/neynar.sh feed --following

Search

bash
# Search casts
scripts/neynar.sh search "ethereum"

# Search users
scripts/neynar.sh search-users "vitalik"

# Search in channel
scripts/neynar.sh search "onchain summer" --channel base

Get Cast

bash
# By hash
scripts/neynar.sh cast 0x1234abcd...

# By URL
scripts/neynar.sh cast "https://warpcast.com/dwr.eth/0x1234"

Post Cast (requires signer)

bash
# Simple cast
scripts/neynar.sh post "gm farcaster"

# Reply to cast
scripts/neynar.sh post "great point!" --reply-to 0x1234abcd

# Cast in channel
scripts/neynar.sh post "hello base" --channel base

# Cast with embed
scripts/neynar.sh post "check this out" --embed "https://example.com"

Reactions

bash
# Like a cast
scripts/neynar.sh like 0x1234abcd

# Recast
scripts/neynar.sh recast 0x1234abcd

Follow/Unfollow

bash
scripts/neynar.sh follow dwr.eth
scripts/neynar.sh unfollow dwr.eth

API Reference

Endpoints Used

Action Endpoint Auth
User lookup GET /v2/farcaster/user/by_username API key
User by FID GET /v2/farcaster/user/bulk API key
User feed GET /v2/farcaster/feed/user/casts API key
Channel feed GET /v2/farcaster/feed/channels API key
Trending GET /v2/farcaster/feed/trending API key
Search casts GET /v2/farcaster/cast/search API key
Get cast GET /v2/farcaster/cast API key
Post cast POST /v2/farcaster/cast API key + Signer
React POST /v2/farcaster/reaction API key + Signer
Follow POST /v2/farcaster/user/follow API key + Signer

Response Format

All responses are JSON. The script extracts key fields for readability:

json
{
  "user": {
    "fid": 3,
    "username": "dwr.eth",
    "display_name": "Dan Romero",
    "follower_count": 450000,
    "following_count": 2800,
    "verified_addresses": ["0x..."]
  }
}

Common Patterns

Monitor a Channel

bash
# Get latest casts from /base channel
scripts/neynar.sh feed --channel base --limit 20

Find Active Users

bash
# Search for users by keyword
scripts/neynar.sh search-users "ethereum developer"

Cross-Post from Twitter

bash
# Post same content to Farcaster
scripts/neynar.sh post "gm, just shipped a new feature 🚀"

Reply to Mentions

bash
# Get your notifications (requires signer)
scripts/neynar.sh notifications

# Reply to specific cast
scripts/neynar.sh post "thanks!" --reply-to 0xabc123

Error Handling

Error Cause Fix
401 Unauthorized Invalid API key Check config.json
403 Forbidden Signer required Set up signer for write operations
404 Not Found User/cast doesn't exist Verify username/hash
429 Rate Limited Too many requests Wait and retry

Signer Setup

For write operations (posting, liking, following), you need a signer:

  1. Go to dev.neynar.com
  2. Create a new signer or use managed signer
  3. Add signerUuid to your config

Managed signers are easiest — Neynar handles the key custody.

Rate Limits

  • Free tier: 300 requests/minute
  • Paid tiers: Higher limits available
  • Check X-RateLimit-Remaining header

Best Practices

  1. Cache user lookups — FIDs don't change, usernames rarely do
  2. Use channels — Better reach than random posting
  3. Engage genuinely — Farcaster culture values authenticity
  4. Batch requests — Use bulk endpoints when possible
  5. Handle rate limits — Implement backoff

Resources

Troubleshooting

API Key Not Working

bash
# Verify key works
curl -H "x-api-key: YOUR_KEY" \
  "https://api.neynar.com/v2/farcaster/user/bulk?fids=1"

Signer Issues

  • Ensure signer is approved and active
  • Check signer permissions match your FID
  • Managed signers are simpler than self-hosted

Cast Not Appearing

  • Casts propagate in seconds, but indexing may take longer
  • Check the cast hash in the response
  • Verify on warpcast.com directly

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