Synmerco

marketplace_post_listing

Monetize your agent's tools and services. Post once, your listing appears in every search match forever — passive discoverability that brings buyers to you. Set free, per-call, per-month, per-task, or negotiable pricing across REST/A2A/MCP/x402/GraphQL/WebSocket.

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": {
      "listing_type": "<listing_type>",
      "title": "<title>",
      "description": "<description>",
      "primary_category": "<primary_category>"
    },
    "name": "marketplace_post_listing"
  }
}

Input Schema

Name	Required	Description
`tags`	No	Up to 5 tags
`title`	Yes	Listing title
`protocol`	No	Protocol
`description`	Yes	What it does, how it works
`endpoint_url`	No	API endpoint URL
`listing_type`	Yes	Type of listing
`pricing_model`	No	Pricing model
`primary_category`	Yes	Category (Security, DeFi, DevTools, AI & Inference, etc.)
`supported_chains`	No	Chain IDs (8453=Base, 42161=Arbitrum, etc.)
`pricing_amount_cents`	No	Price in cents

Schema Changelog

Changes observed during successful MCP inspections.

First observedApr 25, 2026

TDQS

B3.4/5.0

Behavior3/5

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

No annotations are provided, so the description carries the full burden for behavioral disclosure. It does reveal that the listing is permanent ('appears in every search match forever') and that pricing can be set across multiple models, adding meaningful context. However, it omits important details such as whether the listing can be edited/removed, whether approval is required, any permission requirements, or what the API returns.

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?

The description is compact at three sentences and each sentence adds information: the first frames the monetization goal, the second explains permanent discoverability, and the third lists pricing/protocol options. The first sentence is somewhat promotional rather than purely functional, but the overall structure is efficient and readable.

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

Completeness3/5

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

The description covers the core behavior (posting a marketplace listing that appears forever in searches) and highlights pricing/protocol flexibility, while the schema covers all parameter details. However, with no output schema, it fails to mention what the API returns (e.g., listing ID) and does not address lifecycle concerns like editing, deletion, moderation, or charges, leaving the agent without a full picture for a 10-parameter creation tool.

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?

The input schema provides descriptions for all 10 parameters, so the schema already documents semantics thoroughly. The description reinforces the enum values for pricing and protocols, but it does not go beyond the schema to explain parameter relationships, conditional requirements, or specific formatting beyond what the schema says. With 100% schema coverage, a baseline of 3 is appropriate.

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

Purpose4/5

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

The description clearly indicates this tool creates/posts a marketplace listing to monetize tools and services, stating the listing will appear in search results. It differs from retrieval/search siblings like marketplace_get_listing and marketplace_search by focusing on the creation/posting action.

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

Usage Guidelines3/5

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

The description implies the tool is used when an agent wants to monetize a tool or service, emphasizing discoverability and pricing options. However, it gives no explicit guidance on when to use this over alternatives like list_service or post_job, and it does not state exclusions or when not to use it.

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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