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Mellow Hub

by world.mellow.www
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Validate a post

validate_post
Read-only

Checks a post against every channel it names and publishes NOTHING. Returns every problem at once, each naming the channel and the field. Call this before create_post every time — it costs nothing and it is the difference between fixing a post once and learning the rules by publishing badly.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
draftNoKeep it in Mellow as a draft. Nothing is sent to any network. A draft may be unfinished — its media, text or title can come later — and is asked for what it still lacks when it is published or approved.
mediaNoOrdered media. Each entry is a public https URL, or an object with url and an optional thumbnailUrl.
captionNoThe text of the post. Networks with shorter limits can be given their own with perChannel.
optionsNoPer-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky, telegram. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. publishAt (an ISO time, with privacyStatus private) has YouTube hold the upload and make it public then: the post reads published at once, with goesPublicAt on it, until that time, and the library files it as scheduled. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, or the day's trials are used up, a trial reel is never turned into an ordinary one by Hub on its own: it fails, saying so, and nothing is posted. Only ordinaryIfTrialRefused: true (off unless set) lets it go out as an ordinary reel instead, and its settings then carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. Telegram takes silent: true (no notification sound) and disableLinkPreview: true. See mellow://guide/platforms for every field.
channelsYesChannel IDs from list_channels: spc_… for most networks, tgc_… for a Telegram channel.
perChannelNoOverrides for one channel, keyed by channel ID. Accepts caption, media, and that network's options. This is how you give one channel a shorter caption without shortening the post everywhere.
scheduledAtNoISO 8601 time to publish at. Omit to publish immediately.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky, telegram. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, or the day's trials are used up, a trial reel is never turned into an ordinary one by Hub on its own: it fails, saying so, and nothing is posted. Only ordinaryIfTrialRefused: true (off unless set) lets it go out as an ordinary reel instead, and its settings then carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. Telegram takes silent: true (no notification sound) and disableLinkPreview: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky, telegram. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. publishAt (an ISO time, with privacyStatus private) has YouTube hold the upload and make it public then: the post reads published at once, with goesPublicAt on it, until that time, and the library files it as scheduled. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, or the day's trials are used up, a trial reel is never turned into an ordinary one by Hub on its own: it fails, saying so, and nothing is posted. Only ordinaryIfTrialRefused: true (off unless set) lets it go out as an ordinary reel instead, and its settings then carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. Telegram takes silent: true (no notification sound) and disableLinkPreview: true. See mellow://guide/platforms for every field."
  2. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky, telegram. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. Telegram takes silent: true (no notification sound) and disableLinkPreview: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky, telegram. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, or the day's trials are used up, a trial reel is never turned into an ordinary one by Hub on its own: it fails, saying so, and nothing is posted. Only ordinaryIfTrialRefused: true (off unless set) lets it go out as an ordinary reel instead, and its settings then carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. Telegram takes silent: true (no notification sound) and disableLinkPreview: true. See mellow://guide/platforms for every field."
  3. Changed2 schema fields changed
    • changedInput schema / properties / channels / description
      Previous value: -"Channel IDs from list_channels, each beginning spc_."New value: +"Channel IDs from list_channels: spc_… for most networks, tgc_… for a Telegram channel."
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky, telegram. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. Telegram takes silent: true (no notification sound) and disableLinkPreview: true. See mellow://guide/platforms for every field."
  4. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title, and takes description, tags (500 characters together), categoryId, privacyStatus (public, unlisted, private), madeForKids, license, embeddable, publicStatsViewable, recordingDate, containsSyntheticMedia, defaultLanguage and localizations (title and description per language tag, which YouTube takes only with defaultLanguage); a thumbnail for YouTube alone goes on that channel's own media, perChannel.<id>.media[].thumbnailUrl. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."
  5. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. Instagram takes finishInApp: true with soundUrl (the sound's page on Instagram) for a reel whose sound only the Instagram app can choose — a trend's sound from Instagram's library or another creator's original audio: Hub does not post it to Instagram, it sends the person the video, the caption and the sound at the post's time, and the channel reads publishing until they mark it posted. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."
  6. Changed2 schema fields changed
    • changedInput schema / properties / draft / description
      Previous value: -"Keep it in Mellow as a draft. Nothing is sent to any network."New value: +"Keep it in Mellow as a draft. Nothing is sent to any network. A draft may be unfinished — its media, text or title can come later — and is asked for what it still lacks when it is published or approved."
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram decides which public professional accounts may post trial reels (at least 1,000 followers, by the publishing provider's documentation), and Mellow cannot check that first. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram gives trial reels only to accounts with enough followers (Hub's own bar is 200); where it gives none, the reel is not failed — it goes out as an ordinary reel and its settings carry trialReelDeclined. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."
  7. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). Instagram takes trialReelType to post a trial reel, shown first to people who do not follow the account: manual (the owner shares it with followers from the Instagram app) or performance (Instagram shares it with followers by itself if it does well within 72 hours). Only one video posted as a reel can be a trial; a story, picture or carousel with trialReelType is refused (trial_needs_reel). Instagram decides which public professional accounts may post trial reels (at least 1,000 followers, by the publishing provider's documentation), and Mellow cannot check that first. A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."
  8. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). A TikTok that promotes the owner's own product or business takes discloseYourBrand: true (TikTok labels it Promotional content); one another brand paid for takes discloseBrandedContent: true. See mellow://guide/platforms for every field."
  9. Changed2 schema fields changed
    • changedInput schema / properties / media / items / anyOf
      Previous value: -[
-  {
-    "description": "A public https URL.",
-    "type": "string"
-  },
-  {
-    "properties": {
-      "thumbnailTimestampMs": {
-        "description": "Milliseconds into the video to take a poster frame from.",
-        "type": "number"
-      },
-      "thumbnailUrl": {
-        "description": "Poster frame, where the network accepts one.",
-        "type": "string"
-      },
-      "url": {
-        "description": "A public https URL.",
-        "type": "string"
-      }
-    },
-    "required": [
-      "url"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "description": "A public https URL.",
+    "type": "string"
+  },
+  {
+    "properties": {
+      "tags": {
+        "description": "Accounts marked on this item. Instagram and Facebook only, at most 20. Not the same as options.instagram.collaborators: a collaborator co-owns the post and it appears on their profile, a tag marks somebody on the picture. A bare string is an Instagram username.",
+        "items": {
+          "anyOf": [
+            {
+              "description": "An Instagram username.",
+              "type": "string"
+            },
+            {
+              "properties": {
+                "id": {
+                  "description": "Instagram username, Facebook user id, or Instagram product id.",
+                  "type": "string"
+                },
+                "kind": {
+                  "description": "Defaults to user. Products are Instagram only.",
+                  "enum": [
+                    "user",
+                    "product"
+                  ],
+                  "type": "string"
+                },
+                "platform": {
+                  "description": "Defaults to instagram.",
+                  "enum": [
+                    "instagram",
+                    "facebook"
+                  ],
+                  "type": "string"
+                },
+                "x": {
+                  "description": "Fraction from the left edge, 0 to 1. Send with y, or neither.",
+                  "type": "number"
+                },
+                "y": {
+                  "description": "Fraction from the top edge, 0 to 1. Videos and stories take no position.",
+                  "type": "number"
+                }
+              },
+              "required": [
+                "id"
+              ],
+              "type": "object"
+            }
+          ]
+        },
+        "maxItems": 20,
+        "type": "array"
+      },
+      "thumbnailTimestampMs": {
+        "description": "Milliseconds into the video to take a poster frame from.",
+        "type": "number"
+      },
+      "thumbnailUrl": {
+        "description": "Poster frame, where the network accepts one.",
+        "type": "string"
+      },
+      "url": {
+        "description": "A public https URL.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "url"
+    ],
+    "type": "object"
+  }
+]
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest requires boardIds. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."
  10. Changed2 schema fields changed
    • changedInput schema / properties / media / items / anyOf
      Previous value: -[
-  {
-    "description": "A public https URL.",
-    "type": "string"
-  },
-  {
-    "properties": {
-      "tags": {
-        "description": "Accounts marked on this item. Instagram and Facebook only, at most 20. Not the same as options.instagram.collaborators: a collaborator co-owns the post and it appears on their profile, a tag marks somebody on the picture. A bare string is an Instagram username.",
-        "items": {
-          "anyOf": [
-            {
-              "description": "An Instagram username.",
-              "type": "string"
-            },
-            {
-              "properties": {
-                "id": {
-                  "description": "Instagram username, Facebook user id, or Instagram product id.",
-                  "type": "string"
-                },
-                "kind": {
-                  "description": "Defaults to user. Products are Instagram only.",
-                  "enum": [
-                    "user",
-                    "product"
-                  ],
-                  "type": "string"
-                },
-                "platform": {
-                  "description": "Defaults to instagram.",
-                  "enum": [
-                    "instagram",
-                    "facebook"
-                  ],
-                  "type": "string"
-                },
-                "x": {
-                  "description": "Fraction from the left edge, 0 to 1. Send with y, or neither.",
-                  "type": "number"
-                },
-                "y": {
-                  "description": "Fraction from the top edge, 0 to 1. Videos and stories take no position.",
-                  "type": "number"
-                }
-              },
-              "required": [
-                "id"
-              ],
-              "type": "object"
-            }
-          ]
-        },
-        "maxItems": 20,
-        "type": "array"
-      },
-      "thumbnailTimestampMs": {
-        "description": "Milliseconds into the video to take a poster frame from.",
-        "type": "number"
-      },
-      "thumbnailUrl": {
-        "description": "Poster frame, where the network accepts one.",
-        "type": "string"
-      },
-      "url": {
-        "description": "A public https URL.",
-        "type": "string"
-      }
-    },
-    "required": [
-      "url"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "description": "A public https URL.",
+    "type": "string"
+  },
+  {
+    "properties": {
+      "thumbnailTimestampMs": {
+        "description": "Milliseconds into the video to take a poster frame from.",
+        "type": "number"
+      },
+      "thumbnailUrl": {
+        "description": "Poster frame, where the network accepts one.",
+        "type": "string"
+      },
+      "url": {
+        "description": "A public https URL.",
+        "type": "string"
+      }
+    },
+    "required": [
+      "url"
+    ],
+    "type": "object"
+  }
+]
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest requires boardIds. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."
  11. Changed1 schema field changed
    • changedInput schema / properties / options / description
      Previous value: -"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest requires boardIds. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."New value: +"Per-network settings, keyed by platform: instagram, facebook, threads, tiktok, tiktok_business, youtube, x, linkedin, pinterest, bluesky. YouTube requires title. Pinterest pins to the account's first board unless boardIds names one, and a Pinterest video needs a cover: thumbnailUrl on the media item. Instagram and Facebook take placement (timeline, reels, stories). See mellow://guide/platforms for every field."
  12. First observed

TDQS

A4.1/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover the safety profile (readOnlyHint, destructiveHint false), yet the description adds real context beyond them: no publication side effect, no cost, and aggregate error reporting that names the channel and field. It stops short of saying whether validation is versioned or how large a batch it accepts.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three front-loaded sentences; the core behavior and the safety guarantee come first. The closing flourish ('learning the rules by publishing badly') is persuasive rather than informative, but it is brief.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with a large nested schema and no output schema, the description supplies the essential missing pieces: it validates without side effects and returns per-channel, per-field problems. It could note that it validates the full draft surface including scheduling and per-channel overrides.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents channels, media, options, perChannel and scheduledAt. The description adds no parameter-level detail (e.g. whether channels must be a subset of those in the eventual post), which is the correct baseline when the schema carries the load.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Checks a post against every channel it names') plus an explicit non-behavior ('publishes NOTHING'), so the agent can distinguish it from create_post without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear when-to-use directive ('Call this before create_post every time') and a rationale. It does not, however, distinguish itself from the sibling preview_post, which an agent could reasonably confuse with a validation/dry-run check.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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