Skip to main content
Glama
Sign In

Postel

by app.postel
OverviewDiscussionsAdmin

Create draft post

create-post

Save text as a new draft in Postel, optionally with images or videos downloaded from public URLs and a LinkedIn first comment (up to 1250 characters). Does not publish or schedule. Each call creates a separate draft. Drafts are free on every plan.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "content": "<content>"
    },
    "name": "create-post"
  }
}

Input Schema

NameRequiredDescriptionDefault
statusNoPost status (default: DRAFT)
contentYesThe post content
platformNoDestination platform: "x" (default), "linkedin", "bluesky", "mastodon", "youtube", "instagram" or "tiktok"
mediaUrlsNoPublic image or video URLs to download and attach (max 4). X: up to 4 images, or one video or GIF. LinkedIn: images, or one video.
firstCommentNoLinkedIn only: comment posted under the post right after it is published. Max 1250 characters.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changed
    • changedInput schema / properties / platform / description
      Previous value: -"Destination platform: \"x\" (default), \"linkedin\", \"bluesky\", \"mastodon\", \"youtube\" or \"tiktok\""New value: +"Destination platform: \"x\" (default), \"linkedin\", \"bluesky\", \"mastodon\", \"youtube\", \"instagram\" or \"tiktok\""
  2. Changed1 schema field changed
    • changedInput schema / properties / platform / description
      Previous value: -"Destination platform: \"x\" (default), \"linkedin\", \"bluesky\" or \"mastodon\""New value: +"Destination platform: \"x\" (default), \"linkedin\", \"bluesky\", \"mastodon\", \"youtube\" or \"tiktok\""
  3. Changed1 schema field changed
    • changedInput schema / properties / platform / enum
      Previous value: -[
-  "x",
-  "linkedin",
-  "bluesky",
-  "mastodon"
-]New value: +[
+  "x",
+  "linkedin",
+  "linkedin_page",
+  "bluesky",
+  "mastodon",
+  "threads",
+  "youtube",
+  "instagram",
+  "tiktok"
+]
  4. Changed4 schema fields changed
    • changedInput schema / properties / content / description
      Previous value: -"The post content (tweet text)"New value: +"The post content"
    • addedInput schema / properties / firstComment
      Added value: +{
+  "description": "LinkedIn only: comment posted under the post right after it is published. Max 1250 characters.",
+  "maxLength": 1250,
+  "type": "string"
+}
    • addedInput schema / properties / mediaUrls
      Added value: +{
+  "description": "Public image or video URLs to download and attach (max 4). X: up to 4 images, or one video or GIF. LinkedIn: images, or one video.",
+  "items": {
+    "description": "Public http(s) URL of an image or video",
+    "format": "uri",
+    "maxLength": 2048,
+    "type": "string"
+  },
+  "maxItems": 4,
+  "type": "array"
+}
    • addedInput schema / properties / platform
      Added value: +{
+  "description": "Destination platform: \"x\" (default), \"linkedin\", \"bluesky\" or \"mastodon\"",
+  "enum": [
+    "x",
+    "linkedin",
+    "bluesky",
+    "mastodon"
+  ],
+  "type": "string"
+}
  5. First observed

TDQS

A4.2/5.0
Behavior4/5

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so safety is partly covered; the description adds genuinely new context: drafts are never published or scheduled, repeated calls produce duplicate drafts rather than updating, media is fetched server-side from public URLs (consistent with openWorldHint), and drafts cost nothing on any plan. It does not say what is returned (e.g. a draft ID) or mention auth/rate limits, which is why it is not a 5.

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

Conciseness5/5

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

Four short sentences, each carrying distinct information (what it does, what it does not do, duplication behavior, cost). The most decision-relevant negative constraint is front-loaded right after the core action.

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 5-parameter draft-creation tool with annotations and no output schema, the definition covers purpose, exclusions, side effects, and quota. The main remaining gap is that the agent is not told what a successful call yields, but with no output schema that is a minor omission rather than a blocking one.

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%, including platform enums, the 4-item media cap, and the 1250-character LinkedIn comment limit, so the schema already carries parameter meaning. The description only echoes the media-URL and first-comment behavior without adding format or validation detail beyond the schema; baseline 3 applies.

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 (save text as a new draft), names the product (Postel), and explicitly rules out publishing or scheduling. This cleanly separates it from publish-post, schedule-post, and create-posts without the agent needing to open any 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?

The clause 'Does not publish or schedule' gives a clear negative boundary that routes the agent to publish-post/schedule-post for those outcomes, and 'Each call creates a separate draft' tells the agent this is not an upsert. It stops short of naming the sibling alternatives explicitly, so it is strong but not a full when/when-not/alternative triad.

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

All Postel toolsInspect
Try in Browser
One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources