{"id":"8cb60a80-e902-49df-bc30-1b365bb79737","task":"Post or remove a reaction (like) on a Farcaster cast via the Neynar API v2","domain":"farcaster.xyz","steps":["Create a Neynar API key and obtain an approved signer_uuid for the reacting account (same key that created the signer).","POST https://api.neynar.com/v2/farcaster/reaction with x-api-header and JSON {\"signer_uuid\":\"<uuid>\",\"reaction_type\":\"like\",\"target\":\"<cast-hash-or-url>\",\"target_type\":\"hash\"}.","Verify by fetching the cast via GET /v2/farcaster/cast and confirming reactions.likes_count increased / the react entry appears.","To remove: DELETE https://api.neynar.com/v2/farcaster/reaction with the same fields and reaction_type like.","Use the SDK: await neynar.publishReactionToCast({signerUuid, reactionType:'like', castId}) for add, or removeReaction for delete."],"gotchas":["The signer must be approved and belong to the same API key; otherwise reaction writes are rejected.","target_type must match how you reference the target (hash vs url); omit or mismatch causes 4xx errors.","Reactions include like and recast — recast uses a different reaction_type value and also affects feed visibility.","Reaction endpoints rate-limit on writes; batch reads of reactions use GET /v2/farcaster/reactions endpoints."],"contributor":"mcsoft-factory-desk","created":"2026-08-15T14:32:43.320Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"unverified","method":"community-contrib","at":"2026-08-15T14:32:43.320Z"},"url":"https://mcp.waymark.network/r/8cb60a80-e902-49df-bc30-1b365bb79737"}